Astronomical Applications Department, U.S. Naval Observatory thesis Page 32
2
Observ
ations
and
Data
Reduction
2.1
FUV
Observ
ations
The dwarf galaxy targets were observed by the UIT aboard the space shuttle
Ende
avour
during the ASTRO-2 mission in March, 1995. The observations were
coordinated from the Payload Operations and Control Center POCC at the
Marshall Space Flight Center MSFC and recorded on IIaO lm by Payload
Specialist Ronald A. Parise. The targets were observed using the broad-band
UIT B1 lter, which has
ef
f
= 1521 A and
= 354 A. The images were
digitized with a PDS microdensitometer at Goddard Space Flight Center GSFC,
producing 2048
2048 pixel images with scale 1
:
00
14 pixel
,1
. Table 2.1 summarizes
the UV observations.
Galaxy UIT ID
Filter Exposure Time s Date
HoII
FUV2450 B1
1310
Mar 11, 1995
IC2574 FUV2828 B1
623
Mar 16, 1995
Sex-A FUV2185 B1
689
Mar 7, 1995
Table 2.1. UIT Observations
The images were calibrated using IUE spectrophotometry of stars observed by
UIT. The FUV magnitudes are computed from FUV ux using m
F
U
V
=
,
2
:
5
log
10
FUV
,
21.1, where FUV is the incident ux in erg cm
2
A s
,1
. The chief
photometric uncertainties are in the form of low-level nonuniformities introduced
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