Re: [APML] M33 TV-85, ST2000XM

["Richard Crisp" <rdcrisp@earthlink.net>]

----- Original Message -----
From: "Dave Manifold" <dave@davidmanifold.com>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Monday, September 22, 2003 5:36 PM
Subject: Re: [APML] M33 TV-85, ST2000XM


> Hi Bert,
>     The newer ST2000s have a different chip after March 2003.  I have the
> newer chip.  It has the updated KODAK DIGITAL SCIENCET KAI-2001M Image
> Sensor Megapixel Progressive Scan Interline CCD.  So, these combine ratios
> that you posted are for the old chip.  But, still, in most cases I don't
> combine with such a low red ratio.  This is the first time this has
> happened.
> Dave....
>

New chip or not, the interline technology from Kodak (KAI sensors) has very
different characteristics than the full frame (KAF) technology. Because
there is a light-shielded cell adjacent to each light-sensitive pixel, the
overall sensitivity of them is considerably reduced: there's just less
light-sensitive area.

On the other hand there is no need to have a mechanical shutter because the
image is "bulk-transferred" to the light shielded portion of the array in a
single shift operation. They can run much shorter exposures than the KAF
series due to this and they can also be made to operate in an anti-blooming
mode quite easily by modulating the transfer gate.

I think they are great choices for a low-cost sensor to be used for shooting
comparatively bright objects for making pretty pictures, which most of us
care about. I think I'd prefer a traditional full-frame sensor for very
faint objects or photometric applications though.

One man's opinion only, your mileage may vary.
rdc



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