Re: Software to perform inhomogeneous ensemble photometry

[Richard Miles <rmiles.btee@btinternet.com>]

> The software I use, Mira Pro, gives a 1/SNR type uncertainty for each 
> point. It also writes the zeropoint error into the FITS header for each 
> image. I can also (of course) calculate the sigma of the comp star 
> magnitudes. These three different uncertainty values allow me to go nuts 
> computing total uncertainties. I don't know what algorithm Mira uses for 
> the ensemble photometry, but it seems to work pretty well. When you are 
> done the standard deviation of any given comp star is the same as for all 
> the other comp stars. It is basically doing some sort of least squares.
>

Michael Richmond commented that Mira Pro appears to be doing ensemble 
photometry along the lines of his own software and that that other 
photometry software may very well do likewise.

I have as yet not come across suitable commercial software for this job 
although I have not investigated Mira Pro as yet.  I presume it derives 
exo-atmosphere zeropoints for each filter based on airmass calculations on 
all images.  How does it recognise the stars in each frame so that it can 
determine RA and Dec of the plate center ?  If it is an all self-contained 
suite of programmes then it could prove very useful.

I must say that Michael R's photometry of ASAS 002511 is very impressive.

Thanks,
Richard Miles