the level of the sun straylight is assessed during the solar eclipse period in september-october 97. the telescope is pointed to a position on the sky which has a solar aspect angle of 60 degrees. the absolute sky brightness is monitored when entering the umbra period and exiting it. any measurable difference signal can be attributed to sun strayligth. in order to calibrate the signal difference absolutely a measurement on a celestial primary standard is performed on the same revolution. at 170 micron this is the star hr6705 (gamma dra).
Instrument
PHT22
Temporal Coverage
1997-09-07T07:20:30Z/1997-09-07T10:39:30Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the worlds first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
European Space Agency, Ulrich Klaas, 2024, 'PHT SUn straylight assesment C200 celestial standard measurement', 1.0, European Space Agency, https://doi.org/10.5270/esa-hfv4arr
