[BAA Comets] CCD astrometry and photometry

[Roger Dymock]

Good morning all,

It would appear that our procedure does not give correct visual equivalent magnitudes for the
brighter comets. I would therefore recommend that if your mutlibox reports are approaching mag 10
for the larger box sizes that you do not process the results with kphot and report the resulting
magnitude.

I am working on a similar procedure for DSLR cameras which may get us a few more magnitudes. This
method is used by at least one observer who reports to COBS so I will try and pick his brains to
find out how he does it.

My own initial results using AIP4WIN to extract the green channel and then Astrometrica to compute
the magnitudes (stars so far but not comets) seem reasonable. If anyone has a recent DSLR image of a
bright comet could they please send it to me in RAW format along with camera type and when imaged.  

Regards

Roger Dymock
Email: roger.dymock at ntlworld.com
Tel: 023 92647986
Skype: rogerdymock67 or
Skype: rjvdymock
MPC Observatory Code: 940
Project Alcock http://www.britastro.org/projectalcock/