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Re: tn89

Light leaks are a real problem for the Mark IVs which I am correcting on 
the Mark V.  However all the TOMs live in rooms that I can make pretty 
dark.  This allows me to make the screen flats in the daytime.  I am taking 
some screen flats now which I will try to compare to the sky flats.  We 
shall see.

Tom Droege

At 08:21 AM 1/1/03 -0700, you wrote:
>Tom mentioned that you need to cut the brightness down by lots.
>In addition, daytime flats can suffer from light leaks.  It is
>better to perform the same diffuser experiment at twilight.
>Arne
>
>Karen Holland wrote:
>>...following the flat-fielding discussion, has anyone tried creating
>>flat-fields using the daytime sky by covering the aperture with a screen
>>made of the appropriate number of layers of white fabric? I am just about to
>>try this, so would be interested to hear if it is an appropriate method to
>>use.
>>Karen Holland
>>
>>----- Original Message -----
>>From: "Arne Henden" <aah@nofs.navy.mil>
>>To: "TASS List" <TASS@listserv.wwa.com>
>>Sent: Tuesday, December 31, 2002 5:42 PM
>>Subject: tn89
>>
>>
>>>Michael and Tom,
>>>   The main problem with the technical note is the procedure for
>>>flatfielding.  Here, the data frames were combined to create
>>>a master sky flat, which was then applied to the data.  Master......
>>
>>
>
>