Comet Astrometry and Photometry

The basic methodology - or what I did and why I did it

1. TARGET SELECTION - I noticed that some high profile comets were imaged multiple times every day, especially in the period while they are brightening. Others seem to go long periods without a single reported measurement. In general terms I feel that the latter group would yield more useful data than the former.
2. IMAGING - Faint, slow moving comets seem to require two batches of 7x120 seconds taken an hour apart in order to give a positive identification when the two batches are "tracked and stacked" and then blinked in Astrometrica. Bright, fast moving comets can be successfully measured using 15 second exposures only 20 minutes apart. Systematic and well documented experimentation seems to be the key to success here.
3. RESULT SUBMISSION - Astrometrica is virtually fool-proof. Providing you put the right data into the program settings and measure your images carefully you will get a correctly formatted report with positions accurate to sub arc-second quality every time.
4. WHAT HAPPENS NEXT - Observations of comets sent to the Minor Planet Center are published on their web site. Publication can be within a few minutes in the case of the frequently updated Dates of Last Observations of Comets web page or within a few days in the case of the Electronic Circulars. At one point I was responsible for more "dates of last observation" that any other observatory in the world. Having achieved this target I rather lost my enthusiasm for observing comets.

Potential problem areas:-

1. In a few cases the software used by Browser Astronomy that "powers" the New Mexico telescopes does not appear to recognise the standard comet names used by the Minor Planet Center. Scripts using these names will therefore not work - the easiest way around the problem is to use planetarium software to locate a star very close to the predicted position of the comet and to use the GSC name or position of this star as the slew target.

All H06 results submitted to the Minor Planet Center - March 11 to March 25th 2006

A typical period at the Minor Planet Center - note all the H06 activity!

Useful Links

Comets at the Minor Planet Center

Comet Names in the format used by Browser Astronomy and the Sky software

Matching old and new format comet names