Re: [APML] M13 image

[Joe Mize <jmize@globe-net.net>]

Tony;

     Taking Dean's comments into consideration and expanding them to
apply a more scientific regiment to your CCD tests wouldn't you want to
de-focus your camera lens when you take the moonglow image?  Preferably,
I believe you should perform your tests exclusively through your
telescope which would be much more accurate than a camera lens.  Camera
lenses are known for their color focus problems whereas your telescope
is much more highly refined.  Testing a camera lens vs. your telescope
would be like testing a Mustang to judge a Ferrari's performance.

     While you're at it, wouldn't it also be of value to test the tires
(filters) you'll be racing with?  Take a series of RGB images to test
the CCD's response to the individual filters.  You'd then know the CCD's
response to each filter.  Better still, if you have a couple old
filters, test each individually to see if there are different
responses.  That would tell you if you replace an old filter whether or
not you'd want to retest to get new CCD chip performance of the new
filter.  And don't forget to test your DS filter if you use one...joe
:)

Tony Hallas wrote:

> Dean,    As I mentioned to Jerry, as soon as I get a device that will
> allow me to image with a camera lens I am going to shoot a 21 step
> tablet in moonlight with the CCD... if there is anything that is out
> of calibration the steps will not be similar to the tablet... this can
> point out lots of good data, showing where in the density range the
> color might be getting messed up. This does not equal what the sky
> color might be, but it is a good check to see if the color I am
> getting is accurate to a known light source like the sun (reflected
> off the moon). It's a start...     Tony

--
       "May You Go Among The Imperishable Stars"

                              Joe Mize
                      http://sfo.sciastro.net
                  mailto:jmize@globe-net.net
                       Current Moon Phase
       http://tycho.usno.navy.mil/cgi-bin/phase.gif



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