I first window copied the photometry files into Excel for both stars on that night. I then deleted columns that I didn't need. I created a new column for "TJD" which is "Truncated Julian Date" since JD was just too big. I went through and threw out all times where data existed for only one of the two stars. I divided the two counts and computed statistical errors. The resulting Excel file is here: http://nightskylive.net/temp/aql040817.xls .
I found the ratio of both stars to be constant at the 0.1 magnitude level, even when there was significant dimming by clouds! Still, 0.1 magnitudes is a factor of a few above the statisitical error. There is at least one period, though, when errors appear to drop to statistical, at perhaps 0.03 magnitude errors. I tried to save the Excel plot to GIF but MS Paint was the only program that would accept the file, and even then only as BMP. I then opened the BMP file in PhotoShop and saved it to GIF. The result is grainy but you can see the science:
Not all the data is plotted -- I only took the latter part of the day as defined in Universal Time. I conclude that on this night, neither alpha Aql (Altair) nor gamma Aql varied by more than ~0.1 magnitudes over the time scale of a few hours. So add these this data to the hypothetical Night Sky Live Bright Star Catalog (NSLBCC), and go on to look at other stars. Also, one can use Altair as a good comparison star for neighboring stars.
- RJN