RE: [APML] D60/D100 was (new image: IC1396-Provia and halpha CCD)

["Koebel, Alen" <Alen.Koebel@christiedigital.com>]

Roland Christen wrote:

> In a message dated 10/11/2002 11:04:08 AM Central Daylight Time,
> Alen.Koebel@christiedigital.com writes:
>
>> So, I think a cooled two-or three-megapixel CMY-type, 
>> one-shot color CCD camera with 6, 7 or even 8 micron 
>> pixels would satisfy a good many astroimagers. 
>
> It would be somewhat limited in the amount of light 
> reaching the pixels due to the filters. However, if 
> there is a way to extract color info without filters, 
> then there might be an advantage to a 1 shot camera.

The principle behind the Foveon chip, as already mentioned, 
is one such way. But, unfortunately, I think we're a few 
years away from seeing an astronomical camera using such 
a chip (assuming there will ever be one!). 

Regarding the greater light loss through on-chip filters, 
I think this is due to the fact that, for a variety of
very good reasons, these are (AFAIK) simple, dye-based 
filters. They are not interference filters, such as the
better types available for tri-color work, which have 
much better transmission in the passband. 

A few interesting web links relating to "one-shot"
color:  

http://www.sel.sony.com/semi/PDF/ICX249AK.pdf

http://www.starlightccd.com/faq/platt/platt2.htm
http://www.starlightccd.com/faq/platt/platt3.htm

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