Download Astro-Physics Command Center (APCC) Help File

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Astro-Physics Command Center (APCC) Help File
describes it as: "The minimum brightness ratio (sigmas) above background for a star to be detected" and
it lists a value of 3.0 to be the default and the best place to start. Legal values are from 1.0 to 20.0.
Higher values reject dimmer stars that are not sufficiently brighter than the background. For our
purposes in APPM, we have set the default at 4.0. If you are in light-polluted or hazy skies, you may
need to lower this value.
Catalog Max Magnitude: The maximum (fainter) magnitude for selection of stars from the reference
catalog. In certain sections of the sky with lots of stars you may need to lower the maximum magnitude
so that the star limit is not reached, which would cause a plate solve failure. There is also absolutely NO
reason to go deeper than what your imaging system will capture in the allotted exposure time (set in the
Camera Settings Tab).
Catalog Expansion: This parameter determines the the area outside the expected image area from
which the catalog stars will be drawn. Again, to quote the PP documetnation: "By default, PinPoint
retrieves catalog stars to cover the image area plus a 30% expansion along each border of the image.
Thus, with 30% expansion, the area over which the catalog stars are retrieved is (1 + 0.3 + 0.3) squared
or 2.56 times the image area. As the catalog expansion is increased, the number of stars retrieved from
the catalog increases exponentially. The effect of increasing the number of catalog stars is to slow the
plate solution process." Too small a mask, however, risks missing the mark. The default in APPM is
50% which results in 4 times the image area. If your GoTos have been pretty accurate already, you can
probably reduce this to the PinPoint default of 30%. If your GoTos have been off, leave it at 50%.
Max Solve Time (sec): This is the total amount of time allowed to solve the image. If the plate solve
doesn't finish in time then it will be marked as a plate solve failure.
X arc-sec/pixel: This is the approximate image scale of the x-axis. Don't forget to account for binning!
If Refine image scale from solved image is checked then this value will be updated on the first
successful plate solve.
Y arc-sec/pixel: This is the approximate image scale of the y-axis. Don't forget to account for binning!
If Refine image scale from solved image is checked then this value will be updated on the first
successful plate solve.
Image Scale Tolerance: Use this setting to prevent false-positive plate solves. The default is 10%. If
you are sure of your image scale entry (see above), you can tighten this tolerance.
Note: plate solves will be rejected even if successfully solved
when the returned image scale of a plate solve differs
dramatically (more than your defined %) than previously solved
images.
Refine image scale from solved image: When checked the X and Y image scale settings will be
updated with the values in the first good plate solve. It is HIGHLY recommended that this option be
enabled so that APCC won't continuously reject images where the wrong image scale is set.
Test: Clicking this will allow you to test that you have the PinPoint settings correctly setup. A dialog will
open allowing you to navigate to a FITS image which you have previously taken and plate solve it. If the
FITS image does not have embedded RA/Dec coordinates you will have to enter them yourself.
Double Duration if too few stars: If a plate solve fails because of too few stars found this option will
double the duration in an attempt to image more stars.
Settings Tips
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