Subject: Crab flux extractions using different methods

Hello:

Apparently I never managed to send around the plots showing the 
Crab fluxes extracted using different methods and their dependence 
on the off-axis angle. (At least Jerome claims he never got them)

I have extracted fluxes using:

1) my light curve program (taking the difference between well 
illuminated pixels and pixels receiving very little illumination)

2) The midisky source fitting program (fitting the source
model to the observed shadowgrams)

and 3) The midisky backprojected images (counting the excess
counts in the image peak - integrating over 6x6 pixels).

I have not worried about the discrepancies in the normalization
- specifically the normalization for the image extraction is 
particularly uncertain. The flux found with method 2 and 3 
should be increased by a factor 1.33 due to the coded mask imaging
with a 25% open mask - 25 % of the Crab signal appear in the image 
background and will be subtracted from the (less than) 100% of the
signal ideally falling in the peak.

The most significant fact is that the flux now remains pretty 
stable out to 5 degrees off axis for all three extraction methods.

niels

PS: I am on vacation between June 26 (tomorrow!) and July 6.