The available science data products for the EUVE spectrometers and Deep Survey
instrument are stored in two different formats: 1) Binary FITS tables that
include time-tagged events for temporal analysis (e.g. light-curves) and
2) 2-D FITS images of the DS and spectrometers. All 4 instruments are stored
in a single FITS file with 4 extensions. The reductions that produced the 2-D
images are expected to fill the needs of most users, but these can be
re-extracted from the FITS tables.
- EVENTS files (_evt) -- these contain event and monitor data for an observation.
- -- these have timing information
- -- files have names like ex_hya__0005060614N_evt.fits
- IMAGE files (_img) these contain images and filtering data
- -- images include DS Lexan (100 Ang) images and 2-D extracted spectra
- -- files have names like ex_hya__0005060614N_img.fits
CAVEATS-- EUVE was in a low-earth orbit, but only recorded data during
the night time one-third of the orbit. Before March 1995 daytime data
was recored for the SW spectrometer. These day-time files are includes
in the archive with designation "D" in the file name, as opposed to
an "N" for night-time data. EUVE data time because of its greatly increased
background is probably only useful
for the brightest EUV sources, (like White dwarfs).
In general the 4 binary FITS extensions of the EUVE data are:
 DS,  SW,  MW,  LW. However, day-time data only has
one extension, the SW spectrometer, and in some observations EUVE
instruments were turned off to save telemetry slots. In these cases
there are less the 4 extensions and all extension move up a slot,
i.e.. if the DS was off extension  becomes the SW spectrometer.