[BAA Comets] Project Alcock

[Richard Miles]

Denis wrote:

"I received an interesting email from Erik Bryssinck in Belgium about 
cometary ccd photometry, he uses both the FoCAs method for faint comets and 
the CARA method for active and brighter comets."

Erik's approach here sounds to be a very practical one, and one which I 
support. One important difference between these two methods of analysing 
comet images is that FoCAs is used to analyse *unfiltered* images and so can 
go fainter, whereas for the CARA method you must use a Cousins-R filter (not 
normally an R filter from an RGB colour filter set) which then largely 
eliminates the effects of emission bands and so is a measure of the dust 
reflecting sunlight / dust production rate.  Since gaseous emissions arise 
mainly arise for active and brighter comets then this all makes a good deal 
of sense.

Richard Miles