[BAA Comets] Comet magnitudes

[Shanklin, Jonathan D.]

Dear all,

Many of you submit excellent images to the BAA archives, but very few are currently reducing their images to provide visual equivalent magnitudes.  With the general decline in visual observing these are worthwhile measurements to make, particularly for fainter periodic comets, and contribute greatly to the cometary analysis reports that I write for the BAA Journal.  "Fainter" these days generally means anything you can't see in binoculars, though there are a handful of dedicated observers still making telescopic estimates.  We are now getting to the stage where we have data for multiple returns of periodic comets and this allows determination of their long term behaviour.  Could I encourage all imagers to try the procedures at https://www.britastro.org/node/11124 and send their results to me in ICQ format.  They will get used, and more promptly than in the past; the paper on the brighter comets of 2015 has just been accepted for publication, and this includes derived magnitude parameters for fainter comets as well.

Regards,

Jon Shanklin
Visual Co-ordinator, BAA Comet Section
http://www.ast.cam.ac.uk/~jds/


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