TORUS1:[GLL_RAW.INFO]HOW_TO_LOOK_AT_UVS_DATA.DOC  11-june-1996 jjg

This document is intended to give you a basic overview
of how the UVS works so that you have enough information
to do basic plots and data processing on the data.  

Basics:
   The UVS has 3 detectors or channels the F (1616  to 3228 Angstroms),
the N (2818 to 4318 A) and the G (1131 to 1920 A). All three detectors
have 528 grating positions(steps) to cover their wavelength ranges. The
instrument takes data by sequentially scanning the grating of one channel 
for approximately 4 1/3 seconds(6.5 mf). The resulting data and the 18 status 
byte that precede it are called one spectrum.  Spectra can be made in two 
modes, full scan or mini scan. In full scan mode, all 528 grating positions 
are  read out once.  In mini scan mode, a small portion of the grating is 
repeatedly scanned with  an up and down motion.  Miniscans can cover 1,2,3,4,
6,8,11,12,16,22,24,33,44,48,66,88,132,176,264, or 528 grating positions.  
A total of 528 grating postions are always read in one spectrum, so the number
of miniscans is 528/(# of steps covered).
    The alternates scan directions,miniscan sizes,scan positions, and/or 
active channels every other scan, so that two type of spectra are being
taken during the same time.  This information in the status bytes
give information into the mode of each spectra. The grating position and 
detector voltages are used to do this.  Also, UVS data is syncronized to
the space craft clock, so that the spectrum that starts coming out at minor
frame 0 is always the in the first mode.
    UVS playback data is simply the stream of spectra data as it comes out
of the instrument.  The realtime data is a sum of the 2 spectra types. It
is stored in CDS memory and periodically transmitted to the ground.

More Information:
625-270 UVS functional requirements(look on notebook shelves near GLLUVS)
        -- this document contains official description of the instrument.

TORUS1:[GLL_RAW.INFO]UVS_FIDUCIAL.DOC --this file contains information
about UVS fiducial values and what they mean.

Space Science Reviews  Vol 60 p 503 to 518 (on bookshelf closest to Jeremy's
     desk) -- paper on UVS/EUV instruments.

TORUS1:[GLL_RAW.INFO.MICRO_LOADS]UVS_6P1.SRC--last resort! Source code for 
the UVS microprocessor.  The documentation is not as good as EUV, but it
may help. 

DATA FILES:

UVS realtime data is stored in lonarr(1132) files, designed to be used 
with IDL. UVS playback data is stored in intarr(600) files. 
Detailed information about the structure of these records can be found
in TORUS1:[GLL_RAW.INFO]UVS_P2_RTS_HDR.DOC and UVS_P2_PB_HDR.DOC

PROGRAMS:

No Phase2 analysis software has been written for the UVS yet. Details
will be available later.