Tycho Slit Response Functions (SRFs)
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This is a description of the data file tycSRF.txt that provides the
Tycho-instrument Slit Response Functions (SRFs) that have been used in
the Tycho-2 processing. The SRF data file contains 1211 lines and 10
columns.

The first column is the bin number from -605 to +605 in steps of 1
where the bins are in units of samples/90.0. The second column gives
the corresponding angle in units of arcsecond for the case of vertical
slits. The eight last columns are the SRF values in the following
order:

IPU,
IPL,
VPU,
VPL,
IFU,
IFL,
VFU,
VFL,

where V means vertical, I means inclined, F means following, P means
preceding, L means lower, and U means upper. The SRF values refer to
the folded slit response function of the so-called T (= BT + VT) band,
which is the photometric band that has been used in the astrometric
Tycho-2 processing.
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