# Seeing the Bigger Picture :
The _Rosetta_ Mission Amateur Observing Campaign and Lessons for the Future

Helen Usher The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
Colin Snodgrass University of Edinburgh, Institute for Astronomy, Royal
Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK  Simon F. Green
The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK  Andrew Norton
The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK  Paul Roche
School of Physics and Astronomy, Cardiff University, McKenzie House, Newport
Road, Cardiff, CF24 0DE, UK

(Received 29 September 2020; Revised 6 November 2020; Accepted 7 November
2020)

###### Abstract

Amateur astronomers can make useful contributions to the study of comets. They
add temporal coverage and multi-scale observations which can aid the study of
fast-changing, and large-scale comet features. We document and review the
amateur observing campaign set up to complement the _Rosetta_ space mission,
including the data submitted to date, and consider the campaign’s
effectiveness in the light of experience from previous comet amateur
campaigns. We report the results of surveys of campaign participants, the
amateur astronomy community, and schools who participated in a comet 46P
observing campaign. We draw lessons for future campaigns which include the
need for: clarity of objectives; recognising the wider impact campaigns can
have on increasing science capital; clear, consistent, timely and tailored
guidance; easy upload procedures with in-built quality control; and, regular
communication, feedback and recognition.

Comets(280), short period comets, amateur astronomy, astrophotography

††journal: AASPSJ††software: The data analyses were undertaken using Astropy
(Robitaille et al., 2013; Price-Whelan et al., 2018) and Numpy (Harris et al.,
2020). The plots were generated with Matplotlib (Caswell et al., 2020). The
pixel scales were extracted using astrometry.net 363636http://astrometry.net/.
The Google Map was produced using jupyter-
gmaps373737https://github.com/pbugnion/gmaps.

##  1 Introduction

###  1.1 Background

Comets are small, active, volatile-rich, solar system bodies. Each comet is
unique, but a consistent feature is their unpredictability. Their appearance
can change dramatically over very short timescales: brightening or fading,
rapidly or slowly, breaking apart, exhibiting spectacular tails, or not. Their
constituent parts (nucleus, coma, tails and trails) are on significantly
different physical scales: from a nucleus at <10 km to tails and trails which
can extend many AU. Comets have a wide range of orbital elements, which can
change over time due to gravitational perturbations from solar system bodies,
and non-gravitational forces from comet activity (e.g., outgassing). Their
position in the sky can change rapidly. These diverse characteristics make
studying comets exciting, but challenging. Despite being observed and studied
over millenia, comets are still not well understood (A’Hearn, 2004; Meech,
2017). Understanding comet formation and evolution is important in informing
and constraining theories of solar system formation and evolution (A’Hearn,
2017, 2011).

To observe and characterise comet activity requires observations over many
different time periods and intervals, and at different image scales. Observing
a comet over its different apparitions across many years allows its long-term
evolution to be monitored. Multiple observations in a single night can
pinpoint the start of outburst events, while monitoring over subsequent days
and weeks allows morphological changes in the coma, tails, or trails to be
analysed.

Between these extremes, short regular observations allow the comet position to
be measured, refining its orbit and non-gravitational forces, and monitoring
over different time intervals allows analysis of changes due to rotation or
seasons to be undertaken.

As it is impossible to resolve a comet nucleus from Earth, space missions are
required for close-up observations. The Halley missions, _Deep Space 1_ ,
_Stardust_ and _Deep Impact_ close fly-bys provided snap-shot views of the
inner coma and nucleus of five comets. The European Space Agency (ESA)
_Rosetta_ mission to 67P/Churyumov–Gerasimenko, which orbited the comet and
placed the _Philae_ lander on its surface, provided the first opportunity to
observe surface activity and evolution of a comet for over two years around
its perihelion passage.

These missions have been essential to add a ground-truth element to comet
observations, and are resulting in new insights into comet formation and
evolution. Each has been supported and complemented by ground-based observing
campaigns.

###  1.2 Observational Constraints and Opportunities

It can be difficult for professional observers to cover the wide range of
observations needed for analysis of all comets’ dynamic features. Professional
telescope resources are scarce. While the proposal method of allocating
resources is good for long-term regular monitoring, it can be too rigid when a
rapid response is needed to observe short-term changes such as outbursts. Even
long-term monitoring is constrained by over-demand for professional
facilities.

The best observing locations are at altitude and away from light pollution,
clustered and not longitudinally well spread. This is problematic when comet
visibility windows are short, or in periods of bad observing weather. Large
telescopes often cannot image lower than 20-25°elevation due to enclosures,
and many have a minimum solar elongation for safety, but comets are often
brightest and more interesting to study while close to the Sun and often at
low altitude. The image scale of large telescopes produces high resolution,
but with relatively narrow fields of view. Imaging large-scale features, such
as large comae, tails and trails, requires mosaics, taking significant extra
telescope time. As a result, cometary science is an area where amateurs can
still make important contributions, supplementing observations from
professionals.

Amateurs literally observe for love, being able to choose what, when, where
and how to observe. For many, as their interest and expertise deepens they
look for more rewarding targets, transient events, longer-term monitoring
and/or scientific projects (Bowler, 2009). They are free to monitor and
observe comets whenever they are visible and weather conditions allow, and can
respond quickly to alerts when changes in a comet are noted. Subject to
visibility, multiple images can be taken over a long period during a night,
allowing stacking of data to improve signal-to-noise ratios and allowing very
faint features to be detected. Amateurs are spread all across the world, which
is particularly useful when observability windows are small in any one
location due to altitude and hours of darkness. Good longitudinal coverage
allows continuous monitoring for studying rotation effects and transient
features. Some amateurs have excellent unobstructed horizons or have mobile
equipment and can travel to find suitable observing situations. Small
telescopes can safely image closer to the Sun. Finally, comets have large-
scale features (particularly tails and trails) which are well suited to
smaller amateur telescopes with wider fields of view.

Recently, the greatly reduced cost of high-quality camera technology,
telescopes and related equipment, along with sophisticated software, has meant
that many more amateur astronomers can now make high-quality, robust
observations and undertake complex astrometric, photometric and morphological
analyses. The growth of internet technologies and social media has meant that
it is much easier for amateurs to: access databases such as JPL
HORIZONS111https://ssd.jpl.nasa.gov/horizons.cgi giving accurate ephemerides
for planetarium and mount control programs; be alerted to new comets or
activity in known comets; share software and techniques; work to consistent
standards; share observations in active groups; and upload to data archives.
Additionally, amateurs and students now have real-time access to high-quality,
shared telescope facilities (such as iTelescope222 https://itelescope.net/,
Las Cumbres Observatory (LCO)333 https://lco.global/, Slooh444
https://slooh.com/about/about-slooh-education, the Open University’s PIRATE
and COAST 555http://pirate.open.ac.uk/, MicroObservatory666https://mo-
www.cfa.harvard.edu/MicroObservatory/, and other education-orientated
telescope networks). These facilities are located in favourable locations, at
altitude, chosen for good observing and weather conditions (much better than
most observers’ home locations), and robust calibration processes. Robotic
scheduling allows for observing even at inconvenient times.

###  1.3 Pro-Am Comet Campaigns

Amateurs have participated in professionally coordinated observing campaigns
in support of space missions including the _Halley Watch_ and _Deep
Impact/EPOXI_ campaigns, as well as for particularly interesting or well-
placed comets such as C/2012 S1 ISON and the “4*P” Campaign covering the close
approaches to Earth of comets 41P/Tuttle-Giacobini-Kresak, 45P/Honda-Mrkos-
Pajdusakova, and comet 46P/Wirtanen.

The _Rosetta_ mission included a ground-based observation campaign to support
and provide context for the in situ activity (Snodgrass et al., 2017). This
campaign included encouraging amateur astronomers across the world to make and
submit observations.

There are lessons which can be learnt from a review of the organisation and
outputs from these campaigns, to inform future campaigns (e.g., for comet 67P
in 2021), and future comet missions such as Comet Interceptor (Snodgrass &
Jones, 2019).

The _Rosetta_ amateur campaign has not previously been formally documented and
reviewed. This paper presents details of the data currently available from the
campaign. It documents the results of surveys of _Rosetta_ campaign
participants, the amateur astronomer community, and some schools who
participated in a 46P observing campaign, to inform a discussion on good
practice and lessons for future campaigns. While the details may differ, many
of the lessons from this campaign are also relevant to other non-comet
observing campaigns.

##  2 Previous Comet Campaigns

###  2.1 Halley

The ground-based _International Halley Watch_ campaign in 1986 was a major
undertaking, with a budget of $10 million, thoroughly planned and implemented.
The involvement of amateurs was an important element, but was challenging as
electronic communication was in its infancy. Details of positions,
requirements, results etc., all needed to be communicated in hard copy.
Observations were made either visually or with film cameras, and the results
were posted back to the campaign (Edberg, 1988; Sekanina & Fry, 1991; Dunlop,
2003).

The campaign received much publicity and 1,575 people registered, of which 873
submitted observations (Sekanina & Fry, 1991). To ensure consistency, very
detailed guidance was provided. This proved effective, with 90% of astrometric
submissions being used to determine the orbit and so were important for
determining the spacecraft’s trajectory. All the observations were published
in hard copy, digitized and released on CD in the 90s, and then made available
online777https//pdssbn.astro.umd.edu/data_sb/missions/ihw/index.shtml. The
images have also been subjected to modern filtering techniques to draw out
more coma features.

The final report on the amateur involvement (Sekanina & Fry, 1991) noted that:

  * •

astronomers worldwide contributed useful data;

  * •

not all observations made were reported;

  * •

the majority of observers took their efforts seriously enough to submit data;
and

  * •

new observers complied with requirements to a greater extent than experienced
observers. “Do not expect even the most careful and lucid instructions to be
followed rigorously. Even professionals can be wilful on occasion and amateurs
additionally lack the insight to appreciate the importance of standardising
observing technique.”

###  2.2 _Deep Impact/EPOXI_

The _Deep Impact/EPOXI_ mission was designed so that most mission-critical
science was undertaken from Earth to enable a wider range of observations
(A’Hearn et al., 2005). A worldwide ground campaign was needed (Meech et al.,
2005). For the _Deep Impact_ stage (9P/Tempel 1), the observations covered the
full time-range, from pre-mission characterisation, through impact and post-
impact. A Small Telescope Science Program was established to complement the
professional observatories. For the follow-on mission (_EPOXI_) to
103P/Hartley 2 the amateur data contributed significantly to a multi-
wavelength program of near-continuous observations from August 2010 through
encounter on 4 November 2010. The brightness measurements (a key output from
amateur data) allowed the development of an ice sublimation model to estimate
dust emissions (Meech et al., 2005). Initially the program requested amateur
measurements based on their observations; later there was a call for
submission of raw data sets for further analysis to photometric standards.

The CARA888http://cara.uai.it/home (Cometary Archive for Amateur Astronomers)
group was very active (Milani et al., 2007) in observing Tempel 1 around
impact. Their observations covered nearly every clear night over 10 months,
and resulted in 800 photometric observations. It chose to use the $Af\rho$
measure (A’Hearn et al., 1984), allowing comparison of data from different
telescopes, photometric apertures, epochs, and geometrical positions. CARA
members used a consistent set of filters (R and I), took many dozens of images
per observation date (and calibration frames), and checked quality. They
followed a standardised data processing recipe. CARA also provided software to
observers to allow them to analyse and calculate the $Af\rho$ value in a
consistent way (Milani et al., 2007). The measurements allowed an observation
that the $Af\rho$ value increased by 60% following impact and took two days to
return to the previous level.

###  2.3 ISON Morphology Campaign

This 2013 global campaign involved professionals and amateurs, who obtained
mostly continuum images to help characterise dust in the coma of comet C/2012
S1 ISON. ISON was an unusually well-placed and bright comet on a sungrazing
orbit, discovered more than a year before its exceptionally close perihelion
passage, and consequently well studied over a wide range of wavelengths at
professional observatories (Knight et al., 2017; Moreno et al., 2014). The
morphology campaign comprised many hundreds of observations made by nearly two
dozen groups (Samarasinha et al., 2015). When at its brightest the comet was
only visible for a short period each night due to its small solar elongation.
The distribution of amateur observers across the world meant that good
temporal coverage could be achieved. The data were used to constrain the
duration of coma features, look for diurnal changes, constrain grain
velocities, and determine the approximate time grains spent in the sunward
side of the coma. The campaign was managed online999www.psi.edu/ison.
Observers were asked to reduce the data before submitting. The campaign team
then enhanced images to look for coma features. The results were: the data
were far from uniform; few observers had access to narrowband filters (used to
separate gas and dust signatures in the coma); the low altitude of observing
meant high air mass; no features were visible when the comet was at its
brightest, but features were seen earlier in the period. While the challenge
was to deal with the non-uniformity of the data set, the temporal coverage was
of value.

The overall conclusion for the usefulness of the amateur data was “These
campaigns may be most valuable in situations where any single observer can
only obtain data during a small window of time, but contributions from many
such observers…leads to a more complete understanding of the spatial and
temporal evolution of the comet.”(Samarasinha et al., 2015).

###  2.4 4*P Campaign

The Planetary Science Institute ran the 4*P
campaign101010https://www.psi.edu/41P45P46P, starting observations in 2017,
for comets 41P and 45P and in 2018 for comet 46P. The 46P element was
supplemented by a campaign organised by the University of
Maryland111111https://wirtanen.astro.umd.edu. For 46P, 18 amateur observers
submitted observations. These campaigns comprised both professional and
amateur observations.

###  2.5 Other Comet Campaigns

In addition to formal campaigns organised by professional astronomers, there
are ‘informal’ campaigns that are self-organised within the active amateur
comet observing community whenever a particularly bright or interesting comet
appears. It has often been the case that such monitoring discovers interesting
behaviour and triggers observations by professionals with access to larger
facilities, e.g., in the case of a major outburst, such as that of comet
17P/Holmes in 2007 (Miles, 2010).

A recent example of an informal amateur-led campaign of observations was that
for C/2019 Y4 ATLAS. The comet brightened significantly through the early part
of 2020, with predictions for possible naked-eye visibility. It was well
placed for observing for large parts of the night from northern latitudes,
placed close to the zenith, and its appearance coincided with good weather,
and the COVID-19 lockdown. Multiple observers across the world monitored its
development, sharing their observations and analysis primarily via a simple
comet mailing list and some Facebook groups (notably Comet Watch).
Observations were submitted to Comet Observations Database
(COBS)121212https://www.cobs.si/, International Comet Quarterly
(ICQ)131313http://www.icq.eps.harvard.edu/, Minor Planet Center
(MPC)141414https://www.minorplanetcenter.net/ and the British Astronomical
Association (BAA)151515https://britastro.org/cometobs/ (and other) archives.
The comet became very interesting on 19 March 2020 when it started to
fragment. Professional astronomers were alerted to the dramatic changes and
were successful in applying for _Hubble_
observations161616http://tiny.cc/HubbleCometAtlas. There is now a rich, high-
cadence archive available for detailed analysis: 740 and 789 observations in
BAA and COBS archives (at 2020-8-18) respectively (note overlap of datasets).

##  3 _Rosetta_ Campaign

The most ambitious comet mission to date is ESA’s _Rosetta_
mission171717https://www.esa.int/Science_Exploration/Space_Science/Rosetta to
comet 67P/Churyumov–Gerasimenko, with aims to contribute to the study of comet
and solar system origins, and the relationship between cometary and
interstellar material.

It was the first long-term mission to orbit, land on, and ‘live with’ a comet,
making multi-instrument observations for over 2 years. The orbiter instruments
included remote sensors (such as cameras and radio receivers) and direct
sensors (such as dust and particle analysers) (Glassmeier et al., 2007). The
orbiter’s cameras made observations of the comet from distances ranging from
672 million km (when waking from hibernation) to just 2.7 km at closest orbit
(additionally it observed whilst descending to the comet’s surface for its
‘hard landing’). Larger orbits (e.g., at 1500 km) were used to study the
plasma environment and the wider coma. At perihelion the orbiter was at a
distance of $\sim$300 km.

###  3.1 67P Ground-based Campaign Logistics

A ground-based campaign was part of the mission, including both professional
and amateur observations, and coordinated with planning of spacecraft
operations (Snodgrass et al., 2017). The ground- and space-based observations
combined to serve three key purposes:

  * •

monitoring the overall behaviour and activity of the comet in support of the
mission;

  * •

providing a basis for multi-scale studies – e.g., how does the composition of
the coma vary from 10 to 10 000 km from the nucleus? What are the chemical
reactions behind this variation?

  * •

allowing comparison between 67P and other comets, and therefore application of
the _Rosetta_ results to the larger population.

Unfortunately, during the active phase of the mission at the comet (January
2014 – September 2016), 67P was not very favourably positioned for Earth-based
observations. The next apparition, with perihelion in November 2021, is much
more favourable. Observations with large professional telescopes were possible
from late February 2014 until shortly after the _Philae_ landing in November
2014 (Snodgrass et al., 2016), after which the comet was at low solar
elongation for many months. The comet passed through perihelion in August 2015
and was reasonably well placed for observations during the second half of 2015
and the first half of 2016.

The amateur campaign organisation was funded by JPL as part of the NASA
contribution to the ESA-led mission. A website was established by JPL to hold
the main campaign information. This was a static site, with real-time
interactions taking place via a Facebook group
PACA_Rosetta67P181818https://www.facebook.com/groups/paca.rosetta67p (launched
in January 2014 and archived in November 2019). This was used for
communication, sharing guidance, discussions and sharing images. When it was
archived it had 203 members.

The amateur campaign was formally launched in April 2015, following
approximately one year of preparation work in parallel with the early part of
the _Rosetta_ mission (when the comet was still too far from the Sun to be
observable by most amateurs), but initial plans to include amateur astronomers
were already discussed as early as 2011, at the beginning of coordination
efforts for professional observations. The invitation to contribute stated
that ‘All formats of data will be acceptable and encouraged. … CCD, DSLR
images, spectra, sketches, visible observations. …most helpful will be raw,
unprocessed and in FITS format’. Further, more detailed, guidance was issued
on 5 June 2015 with guidelines on what observations were required, including
filters, orientation and format. On filters, ‘at a minimum, continuum images
(UBVRI), but LRGB, or specific narrow band filters (eg OIII) are also
acceptable, for studying colours of the comet. We recommend Sloan r’ and g’
filters for a consistent set of data on dust and gas.’ It was stated that
submissions should include unenhanced images (targets, darks and flats, if
any). The need for accurate time information was stressed.

Each observer was asked to complete a user agreement form, which collected
contact details and some basic information on the telescope(s) to which they
had access. The data format and filename requirements were set out in detail,
along with a request for supplementary information regarding the observations
(context information including date/time, location, camera, filter, exposure
times, position angle, plate scale – but not telescope details). Of the 327
people who registered, 26 FITS format data sets (from individuals or
collaborations) are known to have been submitted. This is a relatively low
number, and it is likely that more amateurs hold observations of comet 67P
which could be usefully added to the data set for the next analytical stage of
this research. Observers are encouraged to contact the lead author if they
wish to contribute observations.

The ESA/Planetary Science Archive (PSA) set up registered user accounts for
FTP upload, which were used by some observers. Although this was intended to
be the single route for all data collection, delays in setting it up (not
available until late September 2015) and initially a lack of clear
instructions and/or assistance in using the FTP protocol meant that most users
did not use it (a campaign member later documented the process for her fellow
observers). Apparent confusion between the requirements for this temporary
collection FTP site and the more complicated rules for permanently archived
data at the PSA also appeared to put off some users. The JPL project manager
set up a Dropbox alternative, and most users submitted this way. These files
were renamed to a standard file-naming convention, which included the date and
time of observation, filter, exposure length and initials of observer. The
intention was for a subset of the observations to be permanently archived and
made publicly available, following some quality assessment. When funding
ceased, the personnel involved moved on to other projects, and this meant work
on collation and archiving effectively ceased. At the time of writing there
are still two separate locations holding data (with overlap). The PSA data
have not been renamed to match the JPL conventions. Table 1 contains data from
both repositories.

As well as the science data in FITS format uploaded to servers, other images
and observations were uploaded to the
Flickr191919https://www.flickr.com/groups/paca_67p/ and/or
Facebook202020https://www.facebook.com/groups/paca.rosetta67p 67P PACA groups.
Certificates of appreciation were made available to those who took part in the
Facebook group, and these were well received.

###  3.2 Data submitted

####  3.2.1 FITS Data

With so many different observers, using such a wide range of equipment and
workflows, and of different experience levels, it is inevitable that the data
set and the associated metadata varies widely in quantity and quality. It is
not always clear whether/how observations have been calibrated/reduced. The
lack of robust metadata was potentially particularly problematic for detailed
analysis - filter and sensor details in particular.

Given the relatively small number of observers, it has been possible to
contact most observers and ask for data and FITS header information to be
verified and supplemented (subsection 4.1). It has not been possible to reach
all observers though as some email addresses appear to be no longer valid, and
contact details are not available for those who did not register initially.

An analysis of the data set (Table 1) shows:

  * •

10,432 observation files known to have been submitted by 26
observers/observing groups covering 284 dates (48 dates and 308 observations
were during the previous perihelion passage in 2008-2009). Figure 1 shows
observations over the main 2015-2016 observing period;

Table 1: Observations Submitted by Amateur Astronomers - FITS Format

Observers | Period | Dates | Obs | Filters | Locations | Obs | ApbbTelescope Aperture | FLccTelescope Focal Length | FOVddImage Field of View | Scale
---|---|---|---|---|---|---|---|---|---|---
|  | (no) | (no) |  |  | CodeaaMPC/IAU Observatory code if applicable. | (mm) | (mm) | (arcmin) | (arcsec/pix)
T Angel and C Harlingten |  2014-07-08 to 2016-03-15 | 89 | 5659 | C |  Spain |  Z85 |  100 |  400 |  11.7x7.79 |  0.92
J Loum |  2015-10-21 to 2016-04-04 | 40 | 1545 | C,Q,R,G |  USA |  W14 |  254 |  1194 |  25.2x18.8 |  1.10
SlooheeThese observers used multiple telescope configurations either locally or remotely. |  2014-11-12 to 2015-07-31 | 46 | 645 | L,R,G,B |  Tenerife, Chile |  G40, W88 |  350, 355, 432 |  3850, 3904, 2929 |  12.8x8.61, 31.3x20.8, 43.4x43.4 |  0.70, 1.41, 1.91
E BryssinckeeThese observers used multiple telescope configurations either locally or remotely., F-J Hambsch |  2014-06-27 to 2016-01-15 | 81 | 469 | C, R |  Chile, Belgium, Australia |  G39, B96, Q62 |  400, 400, 700 |  2700, 1520, 4531 |  47.0x47.0, 36.5x54.7, 27.8x27.8 |  1.38, 0.82, 1.09
N Hidenori |  2015-11-30 to 2016-04-09 | 21 | 423 | L |  Japan |  Q21 |  400 |  1520 |  84.0x84.0 |  1.23
F Garcia |  2008-8-23 to 2016-04-03 | 52 | 329 | Clear |  Spain |  J38 |  250 |  2030 |  17.1x17.1 |  2.00
P Carson |  2105-07-18 to 2016-04-30 | 34 | 324 | L |  UK |  K02 |  315 |  1656 |  36.7x27.7 |  1.32
A Chapman |  2016-01-09 to 2016-03-13 | 4 | 245 | r’ |  Argentina |  |  203 |  807 |  38.2x28.6 |  1.65
A Diepvens |  2015-08-11 to 2016-01-11 | 17 | 207 | L,R |  Belgium |  C23 |  200 |  1350 |  34.5x23.2 |  1.89
M TsumaraffIt has not yet been possible to confirm these data with the observer. |  2015-07-14 to 2016-04-11 | 13 | 120 | C,R,G,B |  ? |  ? |  ? |  ? |  249.0x165.6 |  3.72
P LakeeeThese observers used multiple telescope configurations either locally or remotely. |  2014-03-07 to 2015-08-08 | 5 | 88 | L,V,R,I |  USA |  H06 |  510, 508 |  2260, 2280 |  55.7x55.7, 54.7x36.5 |  1.09, 0.82
W ClarkeeThese observers used multiple telescope configurations either locally or remotely. |  2015-08-13 to 2015-12-02 | 6 | 60 | L,R,G,B |  USA |  H06, U69, H06 |  508, 610, 430 |  2280, 3962, 1939 |  32.1x32.1, 32.1x32.1, 49.0x32.7 |  0.63, 1.26, 0.96
R Castillo |  2015-08-13 to 2016-03-13 | 3 | 54 | L |  Spain |  |  254 |  1194 |  39.6x26.4 |  3.10
J-P Nougayrede, G Arlic, and F Metz, and C Andre, |  2016-03-01 | 1 | 52 | L |  France |  586 |  600 |  2002 |  47.5x31.7 |  0.93
Northolt Branch Obs |  2016-01-15 to 2016-03-05 | 3 | 51 | None |  UK |  Z80 |  71 |  418 |  73.3x54.7 |  3.16
N HoweseeThese observers used multiple telescope configurations either locally or remotely. |  2012-04-25 to 2013-07-05 | 3 | 41 | R |  Australia, USA |  E10, F65 |  2000 |  20000 |  10.2x10.2 |  0.3
T TraubffIt has not yet been possible to confirm these data with the observer. |  2014-7-22 to 2106-03-29 | 8 | 26 | L,R,G,B |  USA |  |  610 |  7788 |  16.4x16.4 |  0.32
J ChamboeeThese observers used multiple telescope configurations either locally or remotely. |  2015-06-24 to 2015-11-19 | 4 | 17 | L,R,G,B |  Australia, USA, USA |  Q62, H06, U69 |  510, 508, 610 |  2260, 2280, 3962 |  32.1x32.1, 32.1x32.1, 32.1x32.1 |  0.63, 0.63, 1.26
J L MaestreffIt has not yet been possible to confirm these data with the observer. |  2015-11-18 | 1 | 15 |  |  Spain |  |  406 |  3900 |  21.7x21.7 |  1.27
P BrlaseeThese observers used multiple telescope configurations either locally or remotely. |  2014-06-17 to 2015-12-19 | 12 | 14 | L,V,R |  Australia, Australia, USA, Spain, USA |  Q62, Q62, U69, I89, H06 |  700, 430, 610, 318, 106 |  4527, 2912, 3962, 2541, 530 |  27.8x27.8, 43.9x43.9, 32.1x32.1, 37.3x24.9, 234x156 |  0.55, 0.64, 0.63, 0.73, 3.51
M Tissington (SARAS) |  2015-10-17 to 2016-01-10 | 5 | 13 | C |  Tenerife |  J54 |  355 |  1877 |  24.4x24.4 |  1.43
R Nicollerat |  2015-10-10 | 1 | 12 | C |  Switzerland |  K17 |  354 |  2937 |  13.5x13.6 |  0.79
T ZwachffIt has not yet been possible to confirm these data with the observer. |  2016-04-07 to 2016-04-08 | 1 | 11 | L,R,V,B |  Spain |  I89 |  150 |  1095 |  111.6x74.4 |  1.67
K Yoshimoto |  2015-07-25 to 2016-03-07 | 5 | 9 | C,V,I |  Japan |  |  160 |  1000 |  35.2x35.2 |  4.1
Isle of Man Observatory |  2016-02-18 to 2016-03-15 | 2 | 2 | None |  Isle of Man |  987 |  406 |  4064 |  9.0x9.0 |  1.06
P Detterline |  2016-01-06 | 1 | 1 | C |  Australia |  |  356 |  1914 |  24.1x16.2 |  0.66

Note. — The table is sorted by the number of images submitted by each
observer.

Figure 1: Number of Amateur Observations 2015-2016

  * •

there is good geographical coverage (Figure 2);

  * •

there is good temporal coverage around perihelion on 13 August 2015, and
around the dates of particular interest identified so far when outbursts were
noted by spacecraft instruments in July, August and September 2015 (Vincent et
al., 2016) (Figure 3);

  * •

there are wide ranges of apertures, fields of view, and pixel scales used for
observations (Table 1);

  * •

some observers made just a small number of observations each night, others
acquired multiple images in different filters;

  * •

Tony Angel and Caisey Harlingten’s data set is by far the largest in number,
with a large number of images per night;

  * •

only 8 observers provided calibration/reduction files (578 files) as requested
in the guidance, although others submitted calibrated images. Some submitted
stacked images rather than unprocessed images;

  * •

993 observations were undertaken with remote telescopes, which have standard
pipeline calibration processes;

  * •

the information in the FITS header does not always conform to the guidance or
to FITS standards;

Figure 2: Observing locations (Blue=Professional, Red=Remote, Green=Local)

  * •

a variety of filters have been used, but primarily standard imaging filters (
Clear, Luminance, Red, Green, Blue) rather than scientific filters (UVBRI or
Sloan r’, g’). In some cases there is no filter data in the FITS header and so
follow up with observers has been needed before analysis;

  * •

the guidance asked for a narrative file providing extra details of the
observations, but these were not generally provided. For some observers, who
did not initially register, this has meant no contact details are available
either.

Figure 3: Number of Amateur Observations Around Perihelion (13 August 2015)

Details of the professional observations submitted to the _Rosetta_ campaign
were obtained. A comparative analysis of the dates of observations was
undertaken. This showed that there were 58 days, during the period 2013-04-17
to 2016-04-30, when amateur observations were available but no professional
data were available. In the 3 months around perihelion (2015-07-01 to
2015-10-01) there were 15 days when only amateur observations were available
(Figure 4). The aim of using amateur observations to improve temporal coverage
has been achieved.

Figure 4: Professional and Amateur Observations Around Perihelion (13 August
2015). The figure shows how amateur observations supplemented the professional
observations, with 15 days during the period 2015-07-01 to 2015-09-30, around
perihelion, when only amateur observations are available.

####  3.2.2 Images

In addition to the submission of FITS data, members uploaded JPEG images to
FLICKR and Facebook. The PACA67/P(Churyumov-Gerasimenko)
FLICKR212121https://tinyurl.com/Paca-67P-Flickr group has 272 ground-based
images (1 July 2020), uploaded by 47 observers. Of these, 36 uploaded $\leq$5,
9 between 6 and 25, and the remaining two, 36 and 56. The majority (77%) also
included scientific analysis, primarily photometric measurements (Figure 5),
but also morphology (Figure 6) and screenshots from
Astrometrica222222http://www.astrometrica.at/. Images at key points in the
comet’s orbit, or significant milestones in the mission, were often uploaded
(Figure 7). Some members also processed data from the mission instruments.

It is much more difficult to catalogue the uploads to Facebook, as the
discussions and uploads relate not only to science data, but also to the
mission more generally, and social and conference elements too. Facebook does
not lend itself to effective cataloguing and archiving of content.

Figure 5: Example of Flickr Upload - scientific analysis of observation on 18
September 2015, wide field showing tail. Credit: Tony Angel and Caisey
Harlingten. Figure 6: Example of Flickr Upload - scientific analysis of
observation of coma on 18 September 2015, including coma morphology. Credit:
Erik Bryssinck. Figure 7: Example of Flickr Upload - Image representing a
significant milestone in the mission - here the last observations on 2016 July
28 and 30. Credit: Wendy Clark/Slooh

###  3.3 Potential Uses for the Amateur Data Set

Amateur data can be used for astrometry, photometry and morphology. Astrometry
measures the comet’s position, which allows study of changes due to non-
gravitational forces caused by comet activity. Characterisation of comet
orbits is important for ensuring effective in-situ measurements, for
predicting possible stellar occultations, and also for monitoring any
potential hazards for Earth. Photometric studies allow the measurement of
total brightness, which allows monitoring of dust and gas production rates,
and how they vary through the orbital/rotational cycles. Coma morphology,
monitoring outbursts and jets from the nucleus, also gives insights into
rotation and pole orientation. Such measurements can be compared with in-situ
data to verify correlations between large-scale and local structures that
could allow interpretation of events in comets not visited by spacecraft.

Photometry can be performed automatically using different apertures to
correspond with different scales at the comet (with pixel scale, and therefore
aperture radius, calculated automatically by querying the
HORIZONS232323https://ssd.jpl.nasa.gov/horizons.cgi database for comet
distance at each observation time). Differential photometry techniques rely on
comparisons with stars in the same frame as the comet. For amateur data there
are two potential challenges to this approach: the robustness of calibration
(particularly flat fielding) which could result in inconsistencies across the
frame; and, knowledge of the filter and CCD response is required to ensure
colour match to catalogue objects. The Af$\rho$ parameter can also be
calculated as a way of comparing results across different telescope apertures
and systems. This is already done under the CARA project.

For morphological study the challenge is obtaining sufficient resolution and
the use of the most appropriate specialist filters (e.g., CN) which are not
generally used by amateurs. Larger amateur telescopes, and the public and
schools access telescopes, such as Slooh and Faulkes telescopes, are capable
of discerning fine transient features. Where there are multiple frames on one
night it is possible to co-add/stack images to improve resolution and signal-
to-noise ratios.

##  4 Surveys

###  4.1 Registered _Rosetta_ Campaign Observers

To improve the robustness of the metadata, and understand the pre-processing
of submitted data, each amateur observer was contacted directly where
possible. Feedback was sought on their experience of the campaign and its
processes, and suggestions for future campaigns. Of particular interest were
the reasons why such a small percentage of those who signed up to the campaign
actually submitted data. The responses were gathered through a Google Forms
survey (Appendix A) which was sent to all those who signed up for the campaign
and who had previously agreed to be contacted (to meet data protection
regulations).

Thirty participants completed the survey, of whom 20 (out of 26) were
observers who had submitted FITS data. This unfortunately meant that the
survey produced little useful data on why observations were not made or
submitted, but it was possible to gather some information from responses to
initial emails. Some people signed up for the campaign as they were interested
in the mission and wanted to be kept informed, so there was never an intention
to submit data. Others suffered from poor observing conditions: weather and
observability (the comet was often poorly placed and visible only during the
early hours of the morning). For some, they could not meet the requirement for
submitting FITS files, having used methods of capture such as DSLRs, although
some of these images were uploaded to Facebook or Flickr sites. Some observers
struggled with the technical requirements including upload.

The main results of the survey are:

  * •

Observers heard about the campaign from a wide range of sources - official
website, group websites (forums, Facebook, societies), email groups, at
conferences, articles in the astronomy and general press, personal
recommendation (particularly Padma Yanamandra-Fisher), and inspiration from
members of the _Rosetta_ team giving talks to local astronomical societies.

  * •

The reasons for sign-up were related to wanting to be part of the _Rosetta_
mission and to contribute to the scientific study of comets.

  * •

While many were experienced observers, who had engaged in campaigns before
(including some involved in _Halley Watch_), some were new to scientific
observing and were looking to enhance their skills and enjoyment.

  * •

Over half (59%) of observations were made primarily for the campaign, 26%
primarily for personal use, with the remainder being mixed use (including
submitting to other data collection organisations such as the BAA and COBS,
and to forums and magazines).

Figure 8: Survey Results from Campaign Participants (Rating - 1:Low, 6:High)

Generally, observers were happy with the guidance provided (Figure 8),
although some commented that publicity for the guidance could have been
better. It became clear later in the process that some of the terminology in
the guidance was interpreted differently between amateurs and professionals
(e.g., professionals refer to the process of applying calibration frames as
’reduction’, amateurs refer to it as ’calibration’, and to an amateur using
Astrometrica ’reduction’ is analysing the data using catalogue matching and
producing measurements of position and
brightness)242424http://tiny.cc/TAngelSeggauPresentation

For those who were members, most found the Facebook page a very useful source
for advice and discussion. The group was a closed group, and this limited
wider sharing of images and engagement. Not all observers got the advice they
needed, and not all of the guidance was implemented by all observers.

There was a wide variation in both software used, and workflows. Just over
half (56%) of observers said they submitted their observations as they made
them, with 44% submitting as a block at the end of the campaign. Some
observers found the upload process difficult (Figure 8). Additionally, it was
suggested that FTP was an unsophisticated approach, and the need to manually
rename, in some cases thousands of, files was onerous.

Observers suggested it would be useful to have verification processes in place
at the start of a campaign to ensure compliance with FITS header requirements,
and highlight any quality or compliance issues for timely resolution.

Tools for determining optimum observations (e.g., exposure times, number of
frames, filters) based on each observer’s equipment, location, and mount
characteristics, would be welcomed. For less experienced users, more detailed
guidance (including walk-through and video guides) would be helpful.

Effective communication is critical to an effective campaign. The survey
results for communication methods show that most amateur astronomers can be
traditional in their preferences for modes of communication, and many do not
use social media. The preference for email lists was common to almost all
(90%) respondents.

A clearer understanding at the outset of the use to which the observations
were to be put would have helped observers make the most useful observations.
Most contributors would welcome more information on the progress of the
campaign, the analysis and results.

A very encouraging finding was that all observers said they enjoyed being part
of the campaign and were likely or very likely to participate in further
campaigns.

###  4.2 Amateur Astronomy Community

A more general survey of the amateur astronomer community was also undertaken
(Appendix B). This was to gauge knowledge of the original campaign and
determine what might encourage greater participation in future campaigns. This
survey was widely disseminated through societies such as the BAA, astronomy
forums, comet mailing lists, Facebook (including the PACA page), Twitter and
via the Royal Astronomical Society’s Specialist Discussion meeting on comets
in December 2019.

Forty-four people responded, from 8 different countries (although 72% were
from the UK, reflecting the distribution methods). Only 2 had submitted data
for the campaign. Fifty-five percent had heard of the _Rosetta_ campaign,
having heard from a range of sources. The main sources cited were: forums (5),
BAA (4), PACA Facebook group, magazines, professional conferences/mailing,
personal contact (2) and web and mailing list (all 2 each). The survey asked a
general question about where observers got their information on comets. (This
was designed to capture data on sources for publicising future campaigns.)
Again there was a wide range: specialist mailing lists (e.g., comets-ml),
forums, newsletters, national associations (such as BAA, Society for Popular
astronomy (SPA), American Astronomical Society (AAS), Astronomy Ireland),
local societies, specialist comet websites (MPC, JPL Horizons, COBS, CARA,
personal websites of specialist comet observers, general astronomy websites
(Astronomy Picture of the Day (APOD), weekly/monthly skyguides), social media
groups (Comet Watch, PACA, on Facebook), magazines, news organisations, remote
telescope operators (e.g., iTelescope), YouTube channels, planetarium software
and word of mouth.

For future campaign communication there was a clear split over social media,
with 47% not wishing to use social media. There was a strong preference for a
dedicated website and/or forum to host all the information for the campaign
and allow discussion, supplemented by a mailing list and regular newsletters.

On guidance, respondents felt that availability, consistency, and detail were
important. Guides should include details of comet observability based on
location, charts on how to find the comet, best equipment to use, and
observing techniques. The level of detail should be tailored to different
observing cohorts (general public, schools, general observers, specialist and
experienced comet observers). The science observations’ guidance should cover
the purpose of the observations, ensuring accurate timing, requirements for
FITS headers, and the provision of calibration files or evidence of
appropriate pipeline processes. All terminology should be clearly explained to
ensure consistency and avoid confusion.

Tools could be developed for planning observations (e.g., to calculate optimum
exposure times based on equipment, the movement of the comet, and the
purpose). The upload process should be simple, incorporate a compliance check
for FITS header information, and automatically generate filenames with the
naming convention. It should be made easy to provide brief context data e.g.,
weather conditions, any issues with the observing.

Where initial analysis was to be undertaken by observers (particularly for
novice observers and schools) detailed walk-through guides, and video
tutorials should be prepared.

Two particularly interesting ideas were: work with mobile app providers (e.g.,
developers of planetarium tools such as SkySafari, Stellarium) to provide both
publicity and guidance as part of the app (e.g., inclusion in ‘Tonight’s best’
recommendations, alerts for observing opportunities); and secondly set up a
mentoring scheme to provide detailed help and guidance. A dedicated forum
would help the community share knowledge, experience and to keep enthusiasm -
as well as disseminating and showcasing results.

To encourage involvement in future campaigns, respondents said that a clear
statement of the scientific value amateurs can add to campaigns was the first
priority, related to campaign aims, objectives and outcomes. All possible
communication channels should be used for initial and ongoing communication –
one size does not fit all. Ideally, a ‘buzz’ should be created around the
campaign, in the mainstream media if possible, magazine, astronomy societies,
videos, web and social media. Outreach and schools’ events would also bring
the campaign to new audiences. The campaign could set up some student
projects, which could report through teacher and learning networks – possibly
linked to societies or academics.

Competitions could be organised to generate wider interest (e.g., first
sighting of comet, best images, best sketch, best with a smart phone). These
images (rather than science data) in a gallery could be a rich source for
publicity and illustration purposes.

The outputs from the campaign, in terms of both scientific output (posters,
conference presentations, research papers, press releases) with amateurs as
co-authors or cited data submitters, and a data archive for future use, should
be regularly reported.

###  4.3 Faulkes Telescope Project Comet 46P/Wirtanen Schools Campaign

A campaign252525http://resources.faulkes-telescope.com/course/view.php?id=150
of observations of comet 46P during its close approach to Earth in 2018/9 was
set up to test the feasibility of running a campaign aimed at schools (through
the Faulkes Telescope Project/Las Cumbres Observatory (Brown et al., 2013))
and to test processes and guidance.

The campaign included developing: background materials on comets; details on
observing 46P including finder charts; walk-through guides for setting up
observations; details of observations required; and, detailed guides for
astrometric, photometric and morphological analysis. The project also provided
some hands-on support for teachers.

In total 2,638 observations were made during the period 1 June 2018 to 30
April 2019 (not all directly from the campaign).

To assess the effectiveness, and learn lessons, a third survey (Appendix C)
was undertaken of those UK schools who had participated. All three submitted
their feedback - see Acknowledgements.

Schools said they chose to participate to inspire their pupils in science and
astronomy, using real research. They heard about the campaign through an
astronomy forum and the Faulkes Telescope Project mailing list. Sixty-two
pupils participated, 30 in primary (state school) and 32 in secondary (private
schools). There was a mix of whole-class participation, astronomy clubs and
individual pupils. All pupils were involved in scheduling observations on the
LCO telescope network, processing and analysing the data. All schools said
their pupils enjoyed being part of the campaign, and that the enthusiasm was
maintained through the three months of the campaign.

The guidance was considered useful, but more-detailed guidance on processing
would have been helpful, perhaps in the form of videos. All felt that a forum
for discussion with other educators would be a useful addition for future
campaigns.

Those leading the work in their school said the project was engaging, it
allowed them to share their love of astronomy and engage their pupils (and
their parents) in comet observations. It provided a catalyst for developing
after-school astronomy observing sessions, and for science activities around
solar observing (during school day).

The educational value was considered to be broad. One school was a girls
school, and this project inspired them to be more involved in physics and
science. Others said the combination of astronomy, physics, chemistry, maths,
geography, and planning (including dealing with different time zones) made for
a rich educational experience. All would like to be involved in future
campaigns.

##  5 Discussion

Pro-Am campaigns have demonstrated that amateurs can add value, particularly
by providing better temporal coverage. What can be learnt from the
effectiveness of these campaigns, and the _Rosetta_ campaign in particular to
inform future amateur campaigns?

Older campaigns had greater logistical challenges due to the lack of modern
communication methods. More modern ones have potentially better communications
and better equipped amateurs . Ensuring adequate mission/campaign resources to
actively manage the planning, implementation and follow up is always a
challenge. Process and cost efficiency is essential, and this means effective
planning, clear guidance, tools for observers, effective initial quality
control, and realistic and robust plans for collecting and archiving the data.

###  5.1 Campaign Objectives

It is important to be clear about the goals of the amateur elements of a
campaign. Obtaining high-quality science data is usually the primary goal, to
allow long-term analysis and short-term alerting of the professionals to
significant changes in the comet. But to look only for the best scientific
data risks missing many other potential campaign benefits, for example:

  * •

increasing science capital by raising awareness of comets, and astronomy, for
the general public. This is particularly important for campaigns in support of
space missions, with their associated large publicly-funded costs.

  * •

deepening the skills, interest and knowledge of amateur observers - adding a
new dimension to their ‘hobby’ (although for many it is a very serious
affair).

  * •

involving schools can increase the interest in astronomy, science and other
related disciplines. It can also widen horizons on career choices. Observing
and studying comets can be a fun vehicle for teaching a wide range of subjects
– as the survey from the 46P noted, students practiced their maths, geography,
physics, biology, chemistry, planning, cooperation and analysis skills. They
gained insights into the way real research is undertaken, including the
challenges of equipment failure, software problems, and weather.

###  5.2 Data Collection

What, where, how and when data should be submitted can be difficult to
optimise. Amateurs do not have to submit their data, and are less likely to do
so if the requirements are perceived to be too onerous, but without compliance
with appropriate standards submitted data can be almost useless.

####  5.2.1 What to Collect?

If the campaign is looking to analyse morphological changes in the comet over
a long period then multiple images stacked, repeated over multiple nights,
will give good SNR to allow faint detail to be teased out. If looking to
constrain the start of outbursts, then the submission of individual accurately
timed, high-cadence images is important (even though these might be low SNR).
Larger aperture telescopes will provide the best resolution, although tracking
is more of a constraint. For large-scale features such as large comae and dust
and gas tails, smaller telescopes with wider fields of view will be most
suited. Longer exposures are also possible before star or comet trailing
becomes an issue.

For some purposes it may be useful to receive the results of analysis, rather
than raw data. An example would be astrometry measurements from standard
software packages such as the widely-used Astrometrica. The CARA project
provided observers with its own developed
software262626http://cara.uai.it/soft_list to measure Af$\rho$ in a consistent
way, and the results were collected and collated, rather than raw data. For
the _Deep Impact_ mission photometric measurements were requested, with raw
data FITS files only submitted later. The _ExoClock_
272727https://www.exoclock.space/ project also provides software and an agreed
methodology (for measuring exoplanet transit lightcurves), as does the Lunar
Impact
Flash282828https://www.nasa.gov/centers/marshall/news/lunar/observing_schedule.html
project (for detecting and measuring lunar meteor strikes). Robust guidelines,
good tutorials, and, ideally, provided software are key requirements for
making these types of submission useful.

The _GAIA_ alert292929http://gsaweb.ast.cam.ac.uk/alerts/home follow-up
project takes a slightly different approach with observers asked to do some
initial data analysis (with Astrometry.net303030http://astrometry.net/ and
Sextractor313131https://sextractor.readthedocs.io/en/latest/) before uploading
the results to a calibration server323232http://gsaweb.ast.cam.ac.uk/followup.
This server calculates magnitude, without needing knowledge of filter used,
and populates a live lightcurve for each _GAIA_ alert object with data points
credited to the observer.

In presenting science results, particularly when engaging with the media, and
engaging schools, it is very helpful to have good-quality colour images of the
comet. Producing colour images from multiple science filters is tricky - not
least because the comet may move significantly between the images taken in
subsequent filters. So a single (or better, stacked) colour image taken with a
standard digital camera or a one-shot-colour astronomy camera can really add
value for publicity and public engagement purposes. For these, precise timing
is not important, nor many details of the capture and processing. This opens
up the campaign to a much broader group of astronomers and even the general
public (as demonstrated by the multiple images of C/2020 F3 NEOWISE posted on
social media and websites).

Clear guidance on what files (images, calibration files), what format (FITS
and what FITS headers, JPEGS, other pictures) and what processing can or
cannot be done is critical. This must be available before the start of the
campaign, and stressed during the campaign - allowing observers to decide
whether they are prepared to spend the time and effort needed for science
observations. Science data should be unprocessed, and to be useful must be
accompanied by specific metadata (e.g., accurate timing, exposure length,
filter, sensor details). Other metadata (e.g., context data) are useful but
not essential. For publicity or educational purposes, JPEGs are acceptable,
and enhancement techniques are useful, while details such as precise timing
are less critical. Given the different levels of rigour needed, it would be
advisable to set up different, clearly differentiated, channels for
submission. The process for pictures could be much simpler.

####  5.2.2 Where to Upload?

The decision on where to upload and how to archive is difficult, particularly
for smaller campaigns. For _Rosetta_ , the ESA’s PSA archive was planned as
the repository. Late set-up, a lack of clear guidance to users, and confusion
over necessary filename conventions, meant that the data and observations were
split between uploading via FTP to ESA storage, a Dropbox facility, FLICKR and
Facebook pages.

While the FLICKR site currently houses a very useful archive of images, the
absence of cataloguing makes it difficult and time-consuming to locate any
specific observations. For Facebook it is even more difficult, and now that
the group (which was members-only) has been archived the images are not
publicly available. Both FLICKR and Facebook rely on private companies for
existence, and their future cannot be guaranteed.

ESA’s PSA archive standards are stringent to ensure long-term accessibility
and compatibility. The time and cost of converting all the amateur data to a
consistent format is unlikely to be a priority for ESA or another agency. For
_Halley Watch_ , all data were initially held in hardcopy, before being
digitised on CD, and made available online at NASA’s PDS: Small Bodies Node.
The _Rosetta_ archive could similarly be stored but not converted into a
future-proof format or catalogued in detail. The filename convention adopted
for upload to the ESA PSA FTP site (Observation date_UTC Time_
Object_Filter_Exposure in seconds_Observer initials.FITS) is good and would be
sufficient for any future researchers to at least identify date of
observation, filter and observer. With an index (of observer and their
equipment and location) this would allow for a quick filtering of observations
for any purpose and this method may be appropriate for future campaigns too.
The challenge is to decide who will provide the storage and the accessibility.
It is also worth noting that even conversion of files to a standard naming
convention appeared to be a barrier to participation to some observers (given
the large number of observations they made), with most of the files uploaded
via Dropbox eventually being renamed by a JPL intern.

####  5.2.3 How and When to Upload?

The key is simplicity but robustness. With modern large-chip, high-resolution
images, file sizes are large. If multiple observations are made over a night
then the amount of data needing to be uploaded becomes multiple Gb. In some
parts of the world this is not an issue, but in remote locations internet
speeds are slow and connection costly. A way of compressing data for upload is
important. Ideally a web-based interface (rather than an FTP or similar
system) needs to be provided with a zipping tool to save bandwidth built in.
Quality control should be built in - verifying FITS headers, and highlighting
non-compliance early enough for corrections to be made. The system should
generate consistent filenames to be used as an access tool. A log should be
kept of all observations uploaded, by observer, with context and contact
details, and this should form a key part of the archive. Ideally, observations
should be uploaded as soon after they are made as possible, along with a short
covering narrative.

####  5.2.4 A Long-term Collaborative Comet Campaign Website and Archive?

The _Halley Watch_ project has demonstrated that having access to a digital
archive can result in extra analysis long after the campaign - data analysis
tools and techniques improve over time. There are currently a number of
organisations who take either observation files or observational data from
amateurs (eg BAA takes JPEG images, COBS and MPC take astrometric and
photometric results). For the latter, consistency of measurement technique
(particularly apertures used) is challenging, and this constrains the
robustness of the data.

If a longer-term, more generic solution is considered (potentially including
professional data too), there are many practical questions to be addressed:
who should host the website and upload facilities, who should store comet
data, how would it be quality-controlled, how long should it be kept, with
what access, and how could the management and support costs funded.

In the short term, in Europe, the Europlanet VESPA333333http://www.europlanet-
vespa.eu/ programme may be able to help. The Planetary Virtual Observatory and
Laboratory (PVOL)343434http://pvol2.ehu.eus/pvol2/ database (Hueso et al.,
2018) is an example of a VESPA-funded project. It makes available planetary
images taken by amateurs across the world, with consistent meta-data.
Unfortunately the Europlanet programme is funded in short-term blocks by the
European Commission, so its long-term future cannot be guaranteed.

###  5.3 Effective Communication

Modern communication methods should make effective communication much easier
than earlier campaigns - although the existence of multiple channels adds
complexity. There is a split between observers who use social media and those
who do not, and this needs to be factored in. A website to hold all the
guidance and tools (including upload), live updates, feedback to observers,
and a discussion forum is the foundation. There are established interactive
mailing lists with a wide membership such as Comets-ml. There are also a few
core comet and Pro-Am Facebook groups. These should be used. Traditional print
media (magazines, newspapers) may be reducing in number, but still have a
place, along with their digital arms, for getting messages out to observers
and the general public. Local and national societies provide good access to
traditional (and often highly-skilled) observers, and internet forums provide
access to active communities too. The personal touch should not be forgotten -
some observers in the _Rosetta_ campaign became involved after a talk at their
astronomy society from the mission scientist Matt Taylor. Two schools were
involved in the 46P campaign due to personal contact with the organiser.
Personal requests from Padma Yanamandra-Fisher also led to experienced
observers joining the campaign.

Core messages and information and guidance need to be consistent however they
are communicated, but modified for specific audiences. Regular communication,
during both the data gathering and subsequent analysis stages, is key to
keeping observers engaged and enthusiastic, as is recognition and credit in
publications.

##  6 Conclusions

###  6.1 Campaign Summary

The comet 67P amateur campaign certainly created interest in the _Rosetta_
mission: 10,432 observations were submitted by 26 observers/groups, covering
284 dates. This compares with 17,352 observations over 463 dates by
professionals. There are 58 days during the main observing period (2013-04-17
to 2016-04-30), and 15 in the 3-month period around perihelion in August 2015
when amateur but no professional data are available. So amateurs have added
significantly to the observational coverage. There is good longitudinal
coverage (Figure 2), and wide scale variations (Table 1).

###  6.2 Surveys Summary

In total 77 people responded to the surveys:

  * •

Observers and the wider astronomy community felt clarity of purpose and
guidance, and regular communication were the most important elements of a
campaign. Data submission should be made straightforward, with tools to ensure
compliance with standards. There was clearly room for improvement in both of
these areas in the _Rosetta_ campaign.

  * •

Useful metadata were collected as part of the survey to supplement/correct
data from FITS headers. Having these data submitted in a consistent format
with the observations would have been better, and should be implemented for
the future.

  * •

Observers really enjoyed being part of the 67P campaign and would wish to be
involved in future.

  * •

Educators said the schools campaign had wide educational benefits, as well as
being enjoyable and inspiring for pupils, staff and parents.

###  6.3 Elements of an Ideal Campaign

The survey results, along with analysis of previous and current amateur
observing campaigns, have informed the following suggested elements of an
ideal campaign. While these are framed in terms of a comet campaign, many of
the principles and actions would also be applicable to other non-comet
campaigns.

  1. 1.

Agree clear aims and objectives for both science outcomes and wider benefits.

  2. 2.

Agree the observations and other data/images to be collected.

  3. 3.

Be realistic, given the resources available to run the campaign, and the
uncertainty of comet brightness.

  4. 4.

Prepare well in advance and learn from other campaigns (re-using material
where appropriate). Involve the amateur community, and the professionals who
will use the data, in the planning.

  5. 5.

Build in a test phase well before the campaign is due to start. This should
include sample observations, by a range of observers, to test the processes,
systems and guidance. The feedback from both observers and researchers will
allow refinement and streamlining (e.g., minimum metadata required, ease of
upload, clarity of guidance), so that the actual campaign data are not
compromised. It will also establish a set of experienced super-users who may
support the community and act as mentors.

  6. 6.

Set up a campaign website to be the information hub: repository for guidance
(at various levels), tools, feedback, forum for discussion, and uploading
data. (In the longer term this could become be an overarching website covering
many campaigns.)

  7. 7.

Carefully consider the launch elements so that the momentum can be maintained.
This may mean launching different elements, for different cohorts, at
different times.

  8. 8.

Use a wide variety of communication routes: press releases, astronomy press,
societies of all sizes, mailing lists, forums and social media. But keep
everything consistent and try to draft once then disseminate, not cover
everything individually. Create a buzz around the campaign by running
competitions (e.g., first sighting, first image with different size
telescopes, art competitions). Contact the main software providers,
particularly app developers, and engage them to include in bulletins,
highlights lists and observing alerts. (This will be dependent on the expected
brightness and observability of the comet.)

  9. 9.

Provide tools for observing: guides to position, optimum observing and
exposure times; ideally these should be tailored for each observer’s location
and equipment (as with _Exoclock_
353535https://www.exoworldsspies.com/en/observers/ project). There should be
more general information for novice observers and more technical for
experienced observers, including details of ideal filter specification.
Develop tools and guidance to allow DSLR users to submit scientific
observations, if the comet is expected to be bright enough, e.g., to ensure
proper timing, as this will open up the campaign to many more observers (see
the deluge of DSLR images of comet C/2020 F3 NEOWISE) and be particularly
useful where viewing conditions are difficult due to low altitude, and/or
short observing windows.

  10. 10.

Where practical the guidance should include multi-media, e.g., short video
tutorials and walk-through guides (particularly for the educational aspects).
Consider setting up a mentoring scheme using experienced amateurs to guide
other amateurs and schools.

  11. 11.

Use the website forum to allow real-time discussion and provision of advice.
Encourage participants to share their observing experiences as well as data.
For educators, encourage them to share how they are using the campaign in
classes and activities.

  12. 12.

For upload, make it easy, ideally with compression to save bandwidth. Keep it
to one location, with timely verification of data submitted via FITS tool,
plus a short narrative for context information. Use a naming convention which
can be used to search for data, but automate file naming on collection rather
than introducing additional complications for observers. Remember that
analysis techniques will improve over time so having an archive will be a
legacy for future astronomers.

  13. 13.

Ideally, following upload there should be a pipeline process to quickly
measure magnitude and position (if the observer has not already reported to
MPC). The magnitude should be logged on a real-time lightcurve, with data
points credited to observers (like _GAIA_). This should be on the front page
of the campaign website.

  14. 14.

Provision of regular updates on what is happening with the campaign and what
research is being undertaken is key to keeping observers engaged and valued
for both the current and future campaigns.

  15. 15.

Recognise all submissions as adding value (e.g., produce certificates of
contribution to campaign).

  16. 16.

Make the final data set freely available, and accessible, using the FAIR
principles (Findability, Accessibility, Interoperability, and Reusable)
(Wilkinson et al., 2016).

  17. 17.

Undertake a post-campaign evaluation to learn and disseminate lessons for
future campaigns.

  18. 18.

Celebrate success.

Comet 67P returns to perihelion in November 2021, and is favourably placed for
observation from ground-based telescopes. This apparition will provide an
excellent opportunity to test the observing campaign principles and good
practice set out in this paper. The resultant data can be analysed alongside
the earlier campaign data to learn more about the evolution of this favourite
comet.

We would like to acknowledge the inspiration of Mike A’Hearn. We hope we can
continue his legacy by supporting Pro-Am comet observing campaigns in the
future. We are grateful to Dr Padma Yanamandra-Fisher for providing insight
into the campaign, and support and encouragement to the amateur observers
during the campaign. Tony Angel and Wendy Clark have freely shared their
practical experiences of participation in the campaign, and their experiences
of observing comets more generally. We thank them. Mary Abgarian provided
access to the amateur data held by JPL and Nicolas Ligier kindly provided data
on the observations from the professional campaign. The Faulkes Telescope
Project provided access to the Las Cumbres Observatory telescope network for
the 46P schools’ campaign. The main contributors to the campaign were St
Mary’s Catholic Primary School, Bridgend; RGS Dodderhill School, Droitwich
Spa; and Marlborough College, Marlborough. We are grateful for the enthusiasm
of their pupils and staff, particularly Ben Wooding, John McGrath and Gavin
James, and hope we have inspired some future comet scientists. We would like
to thank Elizabeth Warner, University of Maryland, for providing information
on the practical administration of previous amateur campaigns and on gathering
observer feedback. These were an invaluable starting point in the design of
the surveys for this work. We thank the reviewers for their helpful and
constructive comments. Last, but certainly not least, we are grateful for the
time, skill and enthusiasm of the observers who have submitted data and
images. In addition to those who submitted FITS data (shown in Table 1), the
following observers submitted images to the PACA Flickr group: P Yanamandra-
Fisher, V Agnihotri, B Backman, A Baransky, J G Bosch, D Buczynski, M Bunnell,
P Camilleri, K Churyumov, G Conzo, P Cox, D Eagle, G Fagiolo, C Feliciano, F
Garcia, J Gonzalez, N James, M Kardasis, R Kaufman, S Kunihiro, D Lovro, A
Maury, G Masi, R Miles, E Morales, R Naves, T Noel, A Novichonok, A Oksanen, D
Peach, T Prystavski, D Romeu, K Sugawara, K Takeshita, J Tillbrook, A Tough, J
Tuten, S White, A Yoneda.

##  Appendix A Survey Questions: Registered _Rosetta_ Campaign Observers

This questionnaire seeks your experience of the Amateur Observing Campaign in
support of ESA’s _Rosetta_ mission to comet 67P. It also invites you to submit
details of any observations, and your opinions on how future campaigns could
build on the _Rosetta_ campaign. This is part of a PhD research project being
undertaken by Helen Usher at the Open University, UK, under the supervision of
Dr Colin Snodgrass. Personal details provided will only be used for the
purposes of this research (at Open University). No personal details will be
released, except to give you credit for the observations you made (and you
will be informed beforehand). If you have any questions on this research
please feel free to contact Helen Usher directly -<EMAIL_ADDRESS>
  1. 1.

What sources do you use for information on comet observing (please give as
many details as possible eg which websites, magazines) ?

  2. 2.

Membership of Astronomy Groups

  3. 3.

How did you hear about the amateur campaign?

  4. 4.

What sources do you use for information on comet observing (please give as
many details as possible eg which websites, magazines) ?

  5. 5.

Why did you sign up?

  6. 6.

Are you an observer, or someone just interested in the campaign?

  7. 7.

Did you make observations?

  8. 8.

If you didn’t make observations, could you briefly explain why not

  9. 9.

Were your observations primarily for personal, primarily to submit to the
campaign?

  10. 10.

Dates of observations

  11. 11.

What guidance did you refer to before making observations?

  12. 12.

Where did you access the guidance? (JPL/ESA/Facebook/Other)

  13. 13.

How easy was it to find the guidance? (1-6)

  14. 14.

How clear and useful was this guidance? (1-6)

  15. 15.

What factors led you to give the score above?

  16. 16.

Did you use a remote shared facility?(iTelescope/Slooh/FT/Other)

  17. 17.

Did you use your own equipment? Location of telescope, description, aperture,
focal length, camera type, make and model, make and type of filters used.

  18. 18.

What software (if any) did you use for acquisition?

  19. 19.

Could you provide details of your acquisition workflow?

  20. 20.

If you calibrated your images before submission what software did you use?

  21. 21.

What was your calibration workflow?

  22. 22.

What software did you use for any processing?

  23. 23.

What was your processing workflow?

  24. 24.

Did you submit your observations?(Y/N)

  25. 25.

If you did not submit could you tell us why not?

  26. 26.

When did you submit observations ?(As I made them/All at once at the end of
campaign)

  27. 27.

Did you submit to (ESA FTP/via P Yanamandra-Fisher/Facebook/Flickr)

  28. 28.

Did you submit (Calibrated FITS/RAW FITS/JPEGS/Calibration files/Context info)

  29. 29.

How straightforward did you find the upload process? (1-6)

  30. 30.

What factors led you to give the score above?

  31. 31.

If you uploaded FITS files did you ensure the FITS headers contained all the
required observation data?

  32. 32.

How could we help you to easily provide these FITS header data in future?
(accurate FITS header data makes analysis much easier and more robust)

  33. 33.

When you registered what were you expecting (including support, guidance, on-
going communication)?

  34. 34.

What sources did you use to obtain the information and guidance on the
campaign (please be as explicit as possible)?

  35. 35.

How well were your expectations and needs met? (1-6)

  36. 36.

What factors led you to give the score above?

  37. 37.

Did you join the Facebook Group?(Y/N)

  38. 38.

If no, could you give details of why not, and what you would have preferred
instead?

  39. 39.

If yes, how useful did you find the Facebook group (1-6)?

  40. 40.

What factors led you to give the score above?

  41. 41.

Did you post images and/or comments?(Y/N)

  42. 42.

If there was a future similar campaign (eg 67P at next apparition) would you
be likely to participate? (Definitely/Probably/Possibly/No)

  43. 43.

Was there any information (or were there any tools) which would have made
observation and upload easier for you?

  44. 44.

What are your preferred methods of communication? (Email mailing
list/Website/Social Media/Dedicated forum/Dedicated group message
board/Regular online newsletters/Magazines/Microsoft teams or similar/Other)

  45. 45.

Is there anything you feel should be done differently for future campaigns?

  46. 46.

Are you aware of any other professional-amateur collaborations and observing
campaigns which are particularly effective, and from which we might draw good
practice lessons?

  47. 47.

How should other observers be encouraged to be part of future campaigns?

  48. 48.

Any other comments/suggestions/complaints/kudos/answers to unasked questions?

  49. 49.

Finally, did you have fun?

##  Appendix B Survey Questions: Amateur Astronomers

The ESA _Rosetta_ mission to comet 67P included an amateur observing campaign.
The aim was to encourage amateurs across the world to submit observations of
the comet, which could then be used to supplement professional observations.
Amateur data can add greater temporal sampling and wider fields of view.

This questionnaire, which forms part of a PhD study by Helen Usher at the Open
University, seeks information on the effectiveness of the awareness raising
methods used, and seeks views on how future observing campaigns could most
effectively reach comet observers worldwide.

The personal details provided for the purposes of this research (at Open
University). No personal details will be released.

If you have any questions on this research please feel free to contact Helen
Usher directly -<EMAIL_ADDRESS>
  1. 1.

Country

  2. 2.

What sources do you use for information on comet observing (please give as
many details as possible eg which websites, magazines) ?

  3. 3.

Membership of Astronomy Groups

  4. 4.

Did you know that there was an official amateur astronomer campaign in support
of the _Rosetta_ space mission to comet 67P? If so, can you remember where you
heard about it?

  5. 5.

Did you participate in the campaign? If you participated in the campaign, have
you received the more detailed survey for participants from Helen Usher? (If
not, it is available here https://forms.gle/iUMeLYMu5SVguAqVA)

  6. 6.

How should observers be encouraged to be part of future campaigns?

  7. 7.

What publicity should be used?

  8. 8.

What guidance and tools should be provided?

  9. 9.

How should the guidance and tools be made available?

  10. 10.

How should ongoing communication be handled?

  11. 11.

Any other comments?

##  Appendix C Survey Questions: 46P Schools’ Campaign Observers

Thank you for participating in the campaign. We hope you enjoyed being part of
it, and it provided good learning opportunities for (you and) your pupils.

This was the first time we have really attempted a comet observing campaign,
but we hope to do more in the future! We would therefore be very grateful if
you could fill in this short questionnaire to let us know what was good and
useful, and what could be improved.

As well as informing future FT/LCO campaigns, Helen Usher will be drawing out
more general lessons as part of her PhD studies with the Open University, UK.

If you are happy for Helen to follow-up then please include your name and
contact details. The data will be kept securely and used purely for the
purposes of this research. No names will be released without prior approval.

Thank you! Helen Usher and the FT team

  1. 1.

Your name, role, school

  2. 2.

School type (Primary/Secondary)

  3. 3.

Why did you decide to observe/be part of the 46P observing campaign?

  4. 4.

How did you hear about the FT campaign?

  5. 5.

How many pupils involved? (age range)

  6. 6.

Did you use the activities with (whole class/astronomy group/individual or
selected pupils)

  7. 7.

What activities did you undertake?

  8. 8.

How much did your pupils enjoy being part of the campaign? (1-6)

  9. 9.

What factors led you to give the score above?

  10. 10.

How much did you enjoy being part of the campaign? (1-6)

  11. 11.

What factors led you to give the score above?

  12. 12.

What do you consider to be the educational value of the campaign?

  13. 13.

How useful was the guidance? [Listed]

  14. 14.

Was there any guidance missing?

  15. 15.

How do you think the guidance could be improved for future campaigns
(particularly any that you rated not useful)?

  16. 16.

What would be your preferred method of communication with the FT campaign team
for guidance etc?(FT website/FT Facebook/Twitter/Email/Discussion
forum/Microsoft teams/In person/other)

  17. 17.

Would it be useful to be able to discuss and share with other schools, and if
so how?

  18. 18.

Would you like to be involved in future campaigns?

  19. 19.

How would you encourage other schools to be involved in future?

  20. 20.

Any other comments?

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