Calculating Field of View, etc.

CCD Calculators are fantastic since they shorten the amount of time youneed to
spending determining some value. However, if you have to wait for the answer...
then their efficiency is greatly decreased.

To that end, you can figure out the answer to your question very quickly. The
only thing you need to remember is a special number 206,265 (it is the number of
acrseconds in a radian). The plate scale (which is what you want to compute) is
equal to 206,265 divided by the focal length of your system. That's it...the
whole formula.

So from the values below the plate scale of this 20inch telescope (in mm) is
206265"/3454mm = 59.72 arcseconds per mm.
But you probably want the answer in arcseconds per PIXEL... so you need to know
the physical size of an EOS 350D pixel. The answer is 6.4microns (0.0064mm). So
just multiply your answer above by this value and you have how many arcseconds a
single pixel is: 59.72"/mm*.0064mm=0.38" .

So there are 0.38 arcseonds per pixel. Now you know the field of view. Just
multiply the number of pixels this camera has (3456x2304) and you will get the
field of view. I did this, and converted to arcminutes you will have a 22'x15'
field of view.

By Adam Block
(external link), from the ))CCDNewAstro(( Yahoo! group.

Created by Andy. Last Modification: Sunday 31 of October, 2010 17:07:01 CDT by Andy. (Version 1)