[Aavso-photometry] Errors on AIP

[Michael Koppelman]

This is an experiment. I know a lot of people use AIP for photometry 
and it doesn't calculate the signal-to-noise ratio (SNR). I have 
created a spreadsheet where you simply paste your AIP data into it and 
it calculates the "total" error in your photometry using the equation:

Err = sqrt( (1/snr)^2 + comp_sigma^2 )

It also calculates your comp star (K-C) sigma for you and tells you the 
SNR and "total" error for each data point.

I would appreciate it is people who use AIP could test it out and let 
me know how it works. I would also appreciate it if those people who 
have a good understanding of SNR could double-check my math.

The spreadsheet is here:

http://www.lolife.com/astronomy/AIP_Err.xls

Cheers,
Michael Koppelman
http://www.lolife.com/astronomy/