Subject: Re: AIs

Hello Carol-Anne:

Regarding the action to provide the tilt values currently used in
j_ima_iros. My values for the collimator tilt are as follows:

           JEM X-1    JEM X-2
tiltX      -0.2 mm    -0.325 mm
tiltY      +0.2 mm    -0.01 

The values are the displacements for the "outward facing" side of the
collimator with respect to the "window side". Expressed in arcminutes
the tilt values become:

           JEM X-1      JEM X-2
tiltX      -12 arcmin   -19.5 arcmin
tiltY      +12 arcmin    -0.6 arcmin

These are values I found from a program minimizing the vignetting
error over many observations of GRS 1915. But many other parameters
were varied during these optimization runs. And I cannot exclude
that equally good results could be obtained with other combinations
of the parameters.

I think it will be necessary to redo these optimizations when j_ima_iros
is completed.

niels








X-Original-To: oxborrow@dsri.dk
Delivered-To: oxborrow@dsri.dk
Date: Fri, 11 Feb 2005 16:02:48 +0100 (MET)
From: Carl Budtz-Jorgensen <carl@uhuru.dsri.dk>
Subject: Re: AIs
To: oxborrow@dsri.dk, nl@spacecenter.dk
Cc: nl@spacecenter.dk, carl@spacecenter.dk, njw@uhuru.dsri.dk, sb@uhuru.dsri.dk
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Hi Carol + Niels,

The collimator tilt values I derived (below) for the rev 239 Crab observations 
do not agree very well with the values of Niels.

          JEM X-1      JEM X-2
tiltX      -1.5 arcmin   +1.5 arcmin
tiltY     -15.8 arcmin   -7.5 arcmin

The values are given in the intrinsic detector coordinate systems and the 
statistical error is about 1 arcmin.

Regards

Carl