The FUSE Archival Data Handbook - MAST - STScI

NOTE 1: Two types of airglow observations were obtained during the course of the mission: i)
dedicated bright-earth observations (see Chapter 9); and ii) airglow exposures obtained as part
of a science program execution. Observations (i) are archived under program codes M106 and
S100. Airglow exposures (ii) are archived with their respective science program codes. They are
assigned exposure numbers > 900 to distinguish them from the regular science exposures. For
further details, see the NOTES in Sections 4.2.1.2, 4.2.1.3, and 4.2.2.1. A separate interface
to retrieve airglow data is available at the MAST archive.
NOTE 2: Separate from airglow observations are sky background observations, found in
programs S405, S505, S605, S705, S805, and S905. The FUSE sky backgrounds program started
in an attempt to get potentially scientifically useful data during thermalization periods prior to
channel alignment activities (when normal science observing could not be done). For programs
S405 and S505 targets, the alignment target was placed at the RFPT and thus the “sky”
position was a randomly-accessed region roughly an arcminute away (exact position dependent
on the roll angle, hence the day of observation). Multiple observations of the same target in
these programs thus do not correspond exactly to the same piece of sky, but for diffuse emission
it was not expected to matter very much.
Beginning in 2005, after the reaction wheel problems, it became useful to define sky positions
in stable regions of the sky, to provide targets for stable pointing when no regular science target
was available. Again, the intent was to obtain science data from periods that would otherwise
have gone to no good purpose. These include programs S605, S705, S805, and S905. These
were all pointed observations, so the given coordinates correspond to the LWRS aperture for
these observations. Hence, multiple observations in these programs correspond to the same
piece of sky, albeit with a different aperture position angle (which should be negligible).
It is gratifying that these observations have resulted in interesting diffuse background measurements.
The reader is referred to Dixon et al. [2006] and references therein.
The alignment scan observations involved stepping a star across the LWRS aperture in each
channel. Correlation of photon events with pointing position and reconstruction of a spectrum
may be possible. However, in most instances the effective exposure time will be short and the
results will not warrant the labor involved.
4.1.3 Notation Convention
Because up to eight spectral files can be produced by a single FUSE exposure, and since a
single observation can be composed of multiple exposures, we introduce a compressed notation
to summarize the different sets of files. In the following, we depict file names as a group of
italic and typewriter type faces, as indicated in Table 4.5.
Table 4.5: Notation
Typeface Group property
italic variable which depends on a specific file
typewriter always present
typewriter array {} each combination is always present.
Two variables that often appear in the file names are the aperture number an = {2, 3, 4}
(see Table 2.1), and the data collection mode = {ttag, hist} (see Section 2.1.7). A target can
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