Sorry, the values I gave below are for the 416, not the 208. I would say
that 10K for a one minute dark seems high.

Ric, don't you use a 216? What are some typical values?

Bob
http://www.usit.com/rfreeze
-----Original Message-----
Date: Tuesday, August 25, 1998 10:12 PM
Subject: [M]: Re: 208/216XT Dark Frame


>I've got the camera temp set at -10C. The values of 4500 (at the top) to
10K
>(at the bottom) are typical for a 1 min exposure.
>
>I did talk with Meade about this today and they weren't overly helpful in
>diagnosing the problem. I think it looks like the camera really isn't
cooling
>or that the cold finger is misaligned with the ccd chip.
>
>Bob Freeze wrote:
>
>> Jerry,
>>
>> I'm thinking the values you're seeing are high. For comparison, I have a
7
>> minute dark from my 208 that has values in the 1700-2000 range, with
peaks
>> at 3000-ish. The dark was done with the camera set to -5C. What temp
are
>> you set at? Temp will make a HUGE difference!
>>
>> Bob
>> http://www.usit.com/rfreeze
>> -----Original Message-----
>> Date: Tuesday, August 25, 1998 2:02 AM
>> Subject: [M]: Re: 216XT Dark Frame
>>
>> >> Hey Guys:
>> >
>> >I've been working with my 216 for a few months now and I was looking at
the
>> pixel
>> >values in a dark frame and I think they are a little out of wack. For a
>> typical 30
>> >sec exposure, the top of the screen is displayed as black with values
in
>> the 4500
>> >range. The frame gets increasingly lighter towards the bottom of the
with
>> the
>> >pixel values increasing to almost 10K. Since the 216 has 64K light
levels,
>> giving
>> >up almost 20% to dark current in the CCD seems excessive.
>> >
>> >Any thoughts?
>> >
>> >
>
>
>
>

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