International Comet Quarterly

The following comets are in great need of observation, both photometric and astrometric -- some having not been observed to our knowledge in quite some time (despite predictions placing them brighter than total magnitude 21), while others have been observed well astrometrically but either (a) very poorly photometrically or (b) the light curve is uncertain (or developing strangely), so that careful total-magnitude photometry is very much desired. Observers are encouraged to send both photometry and astrometry to icqcsc@eps.harvard.edu (with copies of all astrometry *also* to mpc@cfa.harvard.edu).

Even negative observations (where the comet was not detected) are highly useful and should be reported; such reports should include the date (decimal date UT), the limiting stellar magnitude (with bandpass), full instrumentation details (including exposure duration), the amount of sky covered on each side of the line-of-variation (with reference given to where the utilized orbital elements and/or ephemeris were published, along with mention as to whether a "perturbed" ephemeris was used or not).

Comets in need of astrometry and total-magnitude photometry:

• P/2006 Y1 = P/1999 DN_3 (total mag predicted to be in the range 17-20 until Sept. 2010)
• 180P (total mag predicted to be in the range 16-21 until Oct. 2010)
• P/1999 XN_120 (total mag predicted to be in the range 16-19.5 until Oct. 2011)
• P/2010 K2 (WISE)
• C/2010 L3 (Catalina)
• C/2010 L4 (WISE)
• C/2010 L5 (WISE)
• C/2010 M1 (Gibbs)
• P/2010 P4 (WISE)
• C/2010 S1 (LINEAR)

The following comets are not in need of astrometry so much as they are in need of total-magnitude photometry and morphological measurements (coma diameter, tail length and p.a.):

• C/1999 F1 (total mag predicted to be in the range 19-21 from late 2006 into 2010)
• C/2004 T3 (total mag predicted to be in the range 18-21 into 2010)

[last updated 9/25/10]