[BAA Comets] CCD astrometry and photometry

Graham Relf gr at grelf.net
Thu Nov 21 11:28:16 GMT 2013


On 21/11/2013 09:57, Roger Dymock wrote:
> 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/
>
>
>
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Roger,

I got 2013 R1 this week, despite high Full Moon causing sky background. 
The individual RAW frames would be very noisy. I could send you the 
result of stacking 97 frames in FITS format, without any 
post-processing. Would that be of any use?

Regards,
Graham


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