
Delivered-To: oxborrow@dsri.dk
Date: Mon, 6 May 2002 09:44:09 +0200 (MEST)
From: Niels Joergen Westergaard <njw@dsri.dk>
Subject: ADD and bkg
To: sami.maisala@astro.helsinki.fi
Cc: oxborrow@dsri.dk
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Hello Sami,

I'll elaborate here on the comments for your bkg ADD contribution.

Page 109:

   In section 'Function': 'Simulated and observed shadowgram catalogues are
   indexed group tables where each model is a separate FITS file.'
   
   Is it really necessary that they are in individual FITS files? This is
   in contradiction with the ISDC grouping philosophy.
   
   In section 'Instrumental background': 'The results are multiplied with
   each other ...'
   
   Please give some more explanation. It is not clear to me what 'results'
   precisely refers to and why they should be multiplied.

I have some difficulties to follow your description of the subgroups.
Your claim is that there are three important parameters: orbital phase,
sun aspect angle, and radiation level, that will completely determine the
spatial and spectral shape of the background.
The next assumption is that each of these three will give rise to a
particular shape ( you hint at this in the diagram, page 118, where you
suggest that the orbital phase will decide the edge effects, the
sun angle will decide the "skewness" of the background, and the radiation
level will determine the more complicated shape).
So instead of working in a 3-dimensional space (which, admittedly, will be
very complex) you have chosen to work in 3 one-dimensional spaces
that you combine by this multiplication process.

Can you agree with these statements? Or have I got ot wrong?

In either case I hope to have supplied you with some ideas to make the
presentation somewhat clearer.

Best regards

Niels Jrgen
----------
Niels J. Westergaard
Danish Space Research Institute
Juliane Maries Vej 30, DK 2100 Copenhagen O
Phone: +45 35 32 57 05; FAX:  +45 35 36 24 75

