[Aavso-photometry] SNR Calculator

[Michael Newberry]

Monday, in the "Exposures for automated AAVSO observing" thread, Arne 
mentioned the existence of some exposure calculators on-line. I wanted to 
let everyone know that we have one on-line that is very detailed. It 
calculates the V band signal to noise ratio and magnitude uncertainty for 
aperture photometry starting with all basic parameters. We just put this 
on-line in July, so not many people know about it yet. This is a Java 
version of an Excel spreadsheet I made in 1993.  ;-)

To use the SNR calculator, go to http://www.mirametrics.com and select "Web 
Tools" from the left menu. You'll see the calculator's link on that page. 
I'm sorry for the indirect link but that's the way our website was built 
(but not forever).

One interesting use of the SNR Calculator is that you can examine the effect 
of changing things like the measuring aperture, exposure, focal length, 
binning, CCD temperature, sky brightness, etc., or any of the other 19 input 
parameters.

Right now, the default inputs for the "Camera" section assume some Kodak CCD 
specs. We'll be adding some enhancements to the calculator in the near 
future. One of these is to have a selection box for various cameras so their 
parameters can be input easily. If anyone has camera parameters they would 
like to contribute (see the calculator for what is needed), please send them 
to me at support at mirameterics.com.

Comments and suggestions are appreciated.

Thanks,
Michael Newberry