On January 19, 1999, the principal components of the ABRIXAS satellite,
the mirror assembly together with the optical bench and the focal plane
detector including electronics, arrived in the former ROSAT container at
MPE's X-ray test facility
PANTER in Neuried.
There the final calibration of the telescope/detector flight modules
as well as the so-called "end-to-end" tests using the complete chain:
at the German Space Operation Centre (GSOC)
in Weilheim, and real time station at MPE's PANTER facility, were performed.
These tests and calibrations lasted about two weeks and established
the full functionality of the complete chain as it will operate
during the ABRIXAS mission.
The calibration of the telescope/detector unit was essentially two-fold.
One main test was the alignment of the
seven telescope modules with
respect to each other and to the 60 mm × 60 mm
As a result, the optical axis of the central telescope lies within
4 arcmin of the central point of the detector, and the axes of the six
outer telescopes fall within 5 arcmin of the expected circle around
the focal point of the central telescope.
Furthermore, the field of view of each of the seven telescope modules
was scanned by an X-ray beam in two mutally perpendicular directions
at energies of 1.49 and 6.4 keV.
These "cross scans" are used to determine the vignetting of the telescopes
as well as to verify and model their point spread functions, which have to
be precisely known before starting the all-sky survey.
ABRIXAS will be launch with a
Kapustyn Yar located about 150 km east of
tentatively on April 28 of this year.