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Subject: Re: Tri-Color imaging
From: John Wickenhaeuser
Reply To: mapug@shore.net
Date: Tue Feb 07 07:13:14 1995

> I've been wondering whether tri-color is a reality anyway.. With response
> in the blue so low it seems like exposure times have to be VERY long for
> good tri-color work. I've been thinking this about all the cameras based
> upon the Kodak chips.
>
> Anyone care to comment ??

Robert ,

In our experience with the Kodak chip and tricolor imaging you are both right and wrong. The exposures for the dichroic filters that we use typically follow a ration of 1 - 1.2 - 3 for RBG respectively. This does sometimes mean a blue exposure on the order of 15-20 minutes, but with an autoguider and the low noise of the Kodak CCD the images are stunning! Typically we are amazed at the amount of blue in the images. Film as you know is badly biases towards the red, so the images we are used to are really not very accurate. The H - Beta and OIII emission lines contribute to this beautiful blue hue especially in imges of objects like the VEIL nebula.

John