Draft Guidelines for Comet Discoveries
General discovery procedures
If you think you have found a comet, first wait and see if it moves - most
suspect objects don't! A single observation of a fuzzy object with no
evidence of movement is not sufficient to claim a possible comet. Beware of
clusters of faint stars, which can often appear diffuse under low
magnification, and ghost images of bright objects. You must check that no
previously discovered cometary object matches your potential discovery
CBAT web page).
You must also check that there is no deep sky object in the position of
your object (use for example Megastar, Guide or the
Digital Sky Survey). Once you are
reasonably certain that you have found something new, contact the
or the Director. For visual discoveries an accurate
sketch is essential and independent confirmation is a help. For any discovery
you must provide the dates, times and positions of the object. Failure to
provide this information means that you will not be credited with the discovery,
though you may be credited with a pre-discovery observation. You should
also include the rough magnitude, coma diameter, DC and details of any tail.
NB: In the majority of cases it is up to the discoverer to provide
sufficient confirming information. If you only suspect motion and bad
weather prevents further observation report the available information as soon
If you are not worried about gaining credit for your possible discovery, just
supply what information you have. This will be logged for future reference,
but follow up will be made only in exceptional circumstances. Reports of
objects found on single frames of film exposed some time in the past will not
be followed up.
If you discover that an already known comet is much brighter than expected,
first check that there is no deep sky object near the position and that the comet
is not exactly on top of a bright star. If it is then clear
that the comet is in outburst report the fact without delay to the Assistant
Director (Observations) or the Director.
An object that is clearly a comet (for example a diffuse object showing clear
motion or a tail) should be reported to the
or the Director without delay.
You should make a sketch of the field showing the
object and its motion. This can be submitted after any telephone or email
reports. Less obviously cometary objects will require observation on a second
night to confirm the motion and its direction.
A single image is not sufficient to claim a discovery as various photographic
flaws, stray light or ghost images of bright stars can cause comet like images.
Bright stars in the field of a camera lens can create fuzzy comet-like objects,
usually in the opposite quadrant and perhaps 5 - 6 magnitudes fainter. They
will therefore appear on more than one exposure and can on occasion show
motion, for example when photographed using an altazimuth platform. You
must provide at least two images that are sufficiently separated in time to
show clear motion.
A single image is not sufficient to claim a discovery as various CCD flaws,
stray light, ghost images of bright stars and very red stars can cause comet
like images. Bright stars in the field of a camera lens can create fuzzy comet-
like objects, usually in the opposite quadrant and perhaps 5 - 6 magnitudes
fainter. They will therefore appear on more than one exposure and can on
occasion show motion, for example when imaged using an altazimuth
platform. You must provide at least two images that are sufficiently separated
in time to show clear motion and include these with your email report. If
possible reduce the images to provide precise astrometric positions.
Cosmic rays and charged particles near the Earth can make satellite data
very noisy. At least four frames are therefore required to obtain a confirmed
detection of a comet. In exceptional circumstances two or three frames may be sufficient,
for example a clear tail with consistent motion. You should check that the motion is
consistent by plotting your measured X and Y positions against time and this should show a
smooth track. For most objects motion is usually obvious and
you should then email the
leader of the group that operates that particular instrument with details of the positions
and a rough estimate of the magnitude of the object, and contact the
For potential discoveries on SOHO LASCO images first view the discovery guidelines,
then if you are certain that you have found a comet email
Karl.Battams at nrl.navy.mil. For possible objects found in SWAN imagery you should
contact a suitable amateur observer to try and obtain ground-based confirmation, and
inform a member of the SWAN team.
Observers who do not follow the above guidelines risk being blacklisted. If you
report more than two possible discoveries in a twelve month period, which turn out to
be false and where you clearly have not followed the guidelines
you will be blacklisted. In these
circumstances you risk loosing the credit for any discovery that you may report.
You can also refer to the
CBAT guidelines on
comet discovery procedures.
Updated 2009 August 10
Published by Jonathan Shanklin