Straylight in ISOPHOT?

D. Lemke, Th Kranz, U. Klaas, O. Krause, J. Schubert, M. Stickel, L. V. Tóth, J. Wolf

Research output: Contribution to journalConference article


Design measures and preflight tests were the first steps taken to reduce and check for instrumental straylight. Requirements for ISO derived from the natural sky brightness were the basis for relevant preflight studies involving ISO and ISOPHOT. Inspections of the cryostat identified several IR photon leaks. Their elimination was verified by a "Dark background test". In flight, the extended profiles of bright point-like sources were measured to study potential near-field straylight. During solar eclipses the straylight of the Sun and the Moon was searched for. Finally we checked for a potential unwanted signal of the Earth when it fully illuminated the inner sunshade. Surprisingly, the 170 μm Serendipity Survey contributed to our knowledge of instrumental straylight. To summarise, straylight was a negligible contribution to most measurements, but it can be a small correction factor under rare observing conditions near the detection limit.

Original languageEnglish
Pages (from-to)219-224
Number of pages6
JournalEuropean Space Agency, (Special Publication) ESA SP
Issue number481
Publication statusPublished - May 1 2003
EventThe Calibration Legacy of the ISO Mission - madrid, Spain
Duration: Feb 5 2001Feb 9 2001


  • Infrared: general
  • Instrumentation: detectors
  • Instrumentation: photometers
  • Space vehicles: instruments

ASJC Scopus subject areas

  • Aerospace Engineering
  • Space and Planetary Science

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  • Cite this

    Lemke, D., Kranz, T., Klaas, U., Krause, O., Schubert, J., Stickel, M., Tóth, L. V., & Wolf, J. (2003). Straylight in ISOPHOT? European Space Agency, (Special Publication) ESA SP, (481), 219-224.