[Aavso-photometry] Light box question

[Michael Newberry]

How far out from the edge? 5% of the image width? 10%, 20%, etc. You are 
always going to have a poorer correction near the edges.

Michael Newberry

----- Original Message ----- 
From: "Robert J. Modic" <rjmodic at n2net.net>
To: <aavso-photometry at mira.aavso.org>
Sent: Thursday, June 14, 2007 11:10 PM
Subject: [Aavso-photometry] Light box question


> I've been using a light box to take my flats with for a few years
> now and am generally satisfied with this method.  Twilight flats
> are problematic from my site due to weather and time constraints, so
> the light box gives me more flexibility.  However, there are sometimes
> residual artifacts in my images made with light box flats, especially
> in stacked images.  These are usually at the ~1% level and affect
> mainly the edges of the frame.  I'd like to improve on this.
>
> Since my L.B. uses tungsten light bulbs which emit a lot of IR, there
> is a mismatch between that and my night sky which has a fair amount of
> light pollution and, on some nights, moonlight or twilight.
>
> I'm looking for some material that I can place over the front of the
> L.B. to make its output more neutral (white).  Perhaps a light blue
> plastic sheet might accomplish this.  Does anyone have any suggestions
> for specific materials that I could use for this purpose?
>
> Bob Modic (MRV)
>
>
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