HCalSG#2-A4: To define requirements on asteroid models (e.g. wavelength,
              flux range, accuracy requirements, apparent movement
              limitations, frequenccy of observations, units, format,
              model output, ...) for TM to assess and prepare for.

PACS requirements:
* 5-15 asteroids in the flux range between the brightest standard
   stars and the planets, with some overlap with stars (it is not
   possible to have overlap with Uranus and Neptune)
* preferably 2-5 objects available at any time
* pairs of bright asteroids which have during visibility periods
   close encounters (preferably during PV phase) for spatial
   calibration aspects (flux accuracy requirement not important)
* wavelength range for the models: 30 to 250 micron
* best possible flux accuracy (5-15 % at far-IR)
* units: flux density [Jy] over wavelength [micrometer]
* spacing in wavelength: similar to asteroid models for ISO
   (typical interpolation methods should not produce any
    degradation of model quality): about 20 datapoints over the
    PACS wavelength range
* format: - preliminary models for planning purposes in table
             or graphical format
           - final models in FITS format, including model
             parameters in FITS header
* apparent movement on the sky:
    - tools to calculate the HERSCHEL-centric ephemeris,
      and apparent sky movement is required (based on HERSCHEL
      orbit around L2)
    - movement between 0 and 100 arcsec/hour (for some purposes
      even faster HERSCHEL-centric movements would be desirable)
* asteroid models and input parameters should be well documented
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Thomas G. Mueller
Max-Planck-Institut fuer extraterrestrische Physik
Giessenbachstrasse, 85748 Garching, Germany
Phone: +49 89 30000 - 3499; Fax :  3490
E-Mail: tmueller@mpe.mpg.de