Hi Ivo, 
thanks for the report - not too bad !!

Just to be sure that the efficiency computation goes fine:

In the procedure efficiency.prg we used the following formular for the 1.52:

!Compute the photons /A at the 1.5m telescope
comp/table work :phan = {texp}*((1.5*5.5*10**10)/:WAVE)*10**(-0.4*#2)

The factor 1.5 is the effective area Aeff of the telescope in m2.
with  Aeff = Area [m2] * efficiency

For the 1.52 we assumed an efficiency of 0.8 (2 mirrors of 89% reflectivity, no
wavelength dependence). This gives and Aeff=1.5, i.e., the factor in the formula
above.

For the 2.20 we should assume an efficiency for 3 mirrors of 89% reflectivity,
i.e. and efficieny of 0.7. This gives and Aeff = 3.8m2 * 0.7 = 2.65 m2.
If you know the geometrical area better (e.g. taking into account the central
obscuration due to the secondary or use measured reflectivities for the mirrors) 
you could of course provide a more accurate factor (but I think not really
necessary).

So the new formula should read:

!Compute the photons /A at the 2.2m telescope
! Area: 	3.8 m2 = pi*(2.2m/2)2
! Efficiency:	70%     = 3 mirrors of 89%
! -> effective Area 	= 2.65m2
comp/table work :phan = {texp}*((2.65*5.5*10**10)/:WAVE)*10**(-0.4*#2)


Sorry if this was trivial but when I looked at the formula I first got confused
that the factor is 1.5 for the 1.5 telescope ... 

Hope you had already taken this into accout, otherwise the efficiency will be
even lower. Maybe it's also worth to check that you are using the correct gain
if you are still using the spare controller.

Cheers


--
Andreas Kaufer                                                          
Paranal Science Operations                                              
European Southern Observatory   Paranal:  +56 55 43 5337 (ph) 5001 (fax)
Alonso de Cordova 3107          Santiago: +56 2 463 3104 (ph) 3001 (fax)
Santiago 19                     e-mail: akaufer@eso.org                 
CHILE                           URL: http://www.eso.org/~akaufer/