Re: Checking orthogonality during the day

Stuart Heggie <stuart.j.heggie@...>

Joe, my guess is that nothing is going to stop the light down enough to use a ccd camera in daylight. Nothing short of an h-alpha filter for viewing the sun in which case my guess is you won't see any stars (other than the sun) with it.


On Sat, Jun 18, 2016 at 11:15 AM, 'Joseph Zeglinski' J.Zeglinski@... [ap-gto] <ap-gto@...> wrote:

Hi Chris,
    I would like to try “Daytime Ortho adjustment” using daytime target stars,  or  for PemPro alignment runs, but I have a - (possibly unfounded) - concern about using my STL-11000 in broad daylight. I realize CCD’s are even used to photograph the sun’s image – using a special solar filter, but I would hate to end up with a permanent “residual blot” on the sensor.  I discovered a half frame sized residual shadow in the middle of my Full Frame Kodak SLRN (same sensor as STL-11000, I believe),  when its RAW  “image DARKS”  brightness are pushed upward, toward extreme levels. I suspect I caused the DSLR burn from its first, overly long test exposure, on a full moon.
    I fear daytime exposures may damage the sensor, perhaps just using it this way, over some period of time. Also, not sure if I can get the STL’s shutter exposure time down far enough for daylight fast exposures,
    I suppose I could just use a H-alpha filter, but will this process also greatly diminish the star’s brightness, or just the background? Certainly would seem safer for the CCD sensor.
Joe Z.

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