Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE)

Level 0 Downfield Camera Image Data FITS files

August 9, 1996

1.0 Description of the Instrument

The Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) was one of three ultraviolet telescopes on the ASTRO-1 payload which flew aboard the space shuttle Columbia during a nine day mission in December 1990 (December 2 through December 11). WUPPE is a 0.5m f/10 Cassegrain telescope and spectropolarimeter. It obtained simultaneous spectra and polarization measurements, with a spectral resolution of about 10A, from 1400 to 3200A. A set of halfwave plates at 6 different angles provided spectropolarimetric modulation with 10A resolution on point sources through apertures from 6 to 40 arcsec. A "Lyot" analyzer is used to provide 50-100A spectropolarimetric resolution on faint point targets and diffuse nebulae. The typical diffuse object aperture was 3x50 arcsec.

2.0 WUPPE1 Level 0 Zero Order Detector (ZOD) (ASTRO 1-01C):

Field identification, offsetting, focussing, and pointing trim were accomplished by relaying the zero-order image of the Wisconsin Ultraviolet Photo Polarimeter Experiment (WUPPE) spectrometer grating to a blue-sensitive zero-order detector (ZOD) camera. The ZOD was an intensified RCA 320x512 two-dimensional CCD array. The intensifier was an ITT 18 mm proximity-focussed channel intensifier with P-20 phosphor, quartz faceplate, and S-20 photocathode for blue-sensitivity. The array was uncooled and typically read out every second. There are three types of ZOD data; field, zoom and downfield images. No calibrations have been applied to the ZOD images and thus it is Level 0 data. The individual ZOD images are archived in FITS format. The field mode was used for identification and acquisition of the targets. Its size was 3.3 x 4.4 arcmin, 320 x 256 pixels using a 1-bit display. The zoom mode was used for fine pointing and focus. The size of the zoom image was 24 x 32 arcsec, 30 x 40 pixels using a 6-bit grey scale display. The downfield data is similar to the field data except it used the 6-bit grey scale display and was used to produce a more detailed picture of the field around the object of interest.

The fifteen WUPPE1 Downfield Images delivered to NSSDC include all the downfield images taken during the Astro 1 mission.

       WUPPE Downfields Taken During Astro-1

OBJECTID   POINTING-ID  P     MET          QUICK LOOK COMMENT
---------  -----------  -  ----------   -------------------------------  
U-GEM         320811    H  7/22:42:24   something there     
HR1099        350311    H  1/15:37:37   blank               
HR1099        350311    H  1/15:38:00   can see star        
ETA-CARH      420711    W  2/22:50:22   can see something   
CRABNEB       441410    U  3/ 1: 8:06   blank               
M74           620510    U  3/20:47:43   something           
M81           621610    U  3/ 3: 6:38   good                
M81           621611    U  8/ 1:39:27   good                
M82           720510    U  4/ 3:10:46   good, missing one frame (of 16) 
M100          731010    U  3/19:51:25   daylight?          
NGC2146       740411    U  7/23:54:03   something           
NGC1068       820233    H  6/ 2:10:52   good                
M87           830711    U  3/ 6: 8:55   daylight?           
0558-504      840713    H  3/ 7:44:15   something           
1700P64       841513    H  3/22:16:32   something?  missing 2 frames

3.0 WUPPE DOWNFIELD Camera Data FITS File naming convention

3.1 DOWNFIELD FITS file names by Object ID

There is one WUPPE Downfield Image per FITS file.

The files are named as follows:

WUPPE1_OBJECTID_PPPPPP_DN_n.FITS

where,

OBJECTID = The Mission Target List name. The names are common to the HUT, UIT and WUPPE instruments. The number of characters in OBJECT can vary from 3 to 8 characters. May be a mix of numbers and/or alphabetic information. May contain imbedded '-'s.

PPPPPP = The POINTING_ID is a 6 digit number representing the object identification number which was assigned during the ASTRO1 mission. Each shuttle pointing had a unique POINTING_ID number. There may be several pointings of a single object.

DN = Denotes Level 0 ZOD Downfield camera data.

n = A counter.

Sample file name = WUPPE1_NGC1068_820233_DN_1.FITS

3.2 WUPPE DOWNFIELD FITS file names by MET Day Number

A second copy of the DOWNFIELD FITS files were provided to NSSDC, ordered by MET Day number. To generate this data set, the DOWNFIELD FITS files were renamed with the appropriate MET Day number. No changes were made to the CONTENTS of the FITS headers or data. See the table below for names of matching files.

FITS file name = WUPPE1_DAYyz_DN_n.FITS

where,

DAYyz = The mission elapsed time (MET) day number times 10 (eg. 00, 05, 10,... 80). Files are grouped into 12-hour periods for each DAYyz (MET time of y.z).

Matching DOWNFIELD FITS Files

File name by OBJECTID            File Name by DAYyz     
--------------------------------  ----------------------    
WUPPE1_U-GEM_320811_DN_1.fits     WUPPE1_DAY75_DN_1.FITS
WUPPE1_HR1099_350311_DN_1.fits    WUPPE1_DAY15_DN_1.fits
WUPPE1_HR1099_350311_DN_2.fits    WUPPE1_DAY15_DN_2.fits    
WUPPE1_ETA-CARH_420711_DN_1.fits  WUPPE1_DAY25_DN_1.fits    
WUPPE1_CRABNEB_441410_DN_1.fits   WUPPE1_DAY30_DN_1.fits    
WUPPE1_M74_620510_DN_1.fits       WUPPE1_DAY35_DN_1.fits    
WUPPE1_M81_621610_DN_1.fits       WUPPE1_DAY30_DN_2.fits    
WUPPE1_M81_621611_DN_1.fits       WUPPE1_DAY80_DN_1.fits    
WUPPE1_M82_720510_DN_1.fits       WUPPE1_DAY40_DN_1.fits    
WUPPE1_M100_731010_DN_1.fits      WUPPE1_DAY35_DN_2.fits    
WUPPE1_NGC2146_740411_DN_1.fits   WUPPE1_DAY80_DN_2.fits    
WUPPE1_NGC1068_820233_DN_1.fits   WUPPE1_DAY60_DN_1.fits    
WUPPE1_M87_830711_DN_1.fits       WUPPE1_DAY30_DN_3.fits    
WUPPE1_0558-504_840713_DN_1.fits  WUPPE1_DAY30_DN_4.fits    
WUPPE1_1700P64_841513_DN_1.fits   WUPPE1_DAY35_DN_3.fits

4.0 Description of WUPPE Downfield Camera FITS files

The FITS files were written on a Digital DECstation 5000/240 using DEC FORTRAN for Ultrix RISC Systems, running Ultrix 4.2 at the University of Wisconsin. The FITSIO package, version 3.2, written by William Pence at the Goddard Space Flight Center, was used to generate the FITS files.

Each DOWNFIELD FITS file is 158400 bytes in length (310 VMS blocks).

The set of basic header information includes the primary array keywords and keywords describing the instrument, data arrays and the telescope observational and engineering data for the Downfield FITS file.

An example header of a DOWNFIELD FITS file is given below.

Each Downfield image consists of 320x240 integer*2 words. In two cases (see above), there were corrupted or missing frames (out of a total of 16 frames for the Downfield Image). These data have been zeroed out.

5.0 Software

The program "dfldfitsread.for" was written to verify the contents of the Downfield Camera Image FITS files. It also uses the GSFC FITSIO software package. This program, along with other WUPPE1 fortran programs) is available from NDADS. Note that the program only prints data j=121,160 (the center of the image) of the 320 data wide image. SAOIMAGE (on a unix machine) was also used to verify the Downfield Camera Image FITS files.

6.0 FITS File Header

File name = WUPPE1_DAY15_DN_1.FITS and WUPPE1_NGC1068_820233_DN_1.FITS


SIMPLE  =                    T / file does conform to FITS standard             
BITPIX  =                   16 / number of bits per data pixel                  
NAXIS   =                    2 / number of data axes                            
NAXIS1  =                  320 / length of data axis   1                        
NAXIS2  =                  240 / length of data axis   2                        
COMMENT   WUPPE Downfield Image:320x240 data points                             
CTYPE1  = 'Pixel   '           / Pixel Number                                   
CRPIX1  =                  1.0 / Reference pixel location                  
CRVAL1  =                  1.0 / Reference pixel starting value            
CDELT1  =                  1.0 / Delta pixel number                             
CTYPE2  = 'Row     '           / Row Number                                     
CRPIX2  =                  1.0 / Reference row location                    
CRVAL2  =                  1.0 / Reference row starting value                
CDELT2  =                  1.0 / Delta row number                               
ORIGIN  = 'UW-Space Astronomy Lab' / Creator of FITS file                       
DATE    = 'Tue Apr 13 20:16:28 1993' / Date FITS file was created               
OBSERVAT= 'ASTRO-1 '           / Observatory                                    
TELESCOP= 'WUPPE   '           / Telescope                                      
INSTRUME= 'SPECTROPOLARIMETER' / Instrument Used                                
OBJECT  = 'NGC1068 '           / Object Observed                                
ID      = '8202-33 '           / Target ID                                      
PRIME   = 'HUT     '           / Prime Instrument                               
EQUINOX =              1950.00 / Equinox for coordinates                        
RA      =              40.0295 / Right ascension in degrees                     
DEC     =              -0.2254 / Declination in degrees                         
GMTTIME = '342/ 8:57:30'       / GMT time of data readout                       
METTIME = '6/ 2: 8:29'         / MET time of data readout                       
BOS     =                 25.0 / Bright Object Sensor reading                   
END

7.0 Further Information

Additional information on WUPPE can be found in the WUPPE1_GENINFO.DOC.

For further assistance, please contact the MAST staff by sending mail to archive@stsci.edu

Ms. Marilyn Meade
UW Space Astronomy Laboratory
Chamberlin Hall
1150 University Avenue
Madison, WI 53706
Phone (608) 263-4678
meade@sal.wisc.edu

This documentation orginally provided to GSFC/NSSDC by the WUPPE project.