FITS Headers
DIRBE_SSO_P3B_PALLAS.FITS
Primary Header
SIMPLE = T / file does conform to FITS standard BITPIX = 32 / number of bits per data pixel NAXIS = 0 / number of data axes EXTEND = T / FITS dataset may contain extensions COMMENT FITS (Flexible Image Transport System) format defined in Astronomy and COMMENT Astrophysics Supplement Series v44/p363, v44/p371, v73/p359, v73/p365. COMMENT Contact the NASA Science Office of Standards and Technology for the COMMENT FITS Definition document #100 and other FITS information. DATE = '11/08/97' / FITS file creation date (dd/mm/yy) DATE-MAP= '04/04/96' / Date of original file creation (dd/mm/yy) ORIGIN = 'CDAC ' / Cosmology Data Analysis Center TELESCOP= 'COBE ' / Cosmic Background Explorer satellite INSTRUME= 'DIRBE ' / COBE instrument [DIRBE, DMR, FIRAS] OBJECT = 'PALLAS ' / part of sky given [e.g., ALL-SKY, WEEKLY-SKY, COMMENT / DAILY-SKY, GAL-SLICE, FACE ...] EQUINOX = 2000.0 / equinox of coords in following tables COMMENT / unless otherwise specified REFERENC= 'COBE/DIRBE Explanatory Supplement,' / REFERENC= 'ed. M.G. Hauser, T. Kelsall, D. Leisawitz, and J. Weiland,' / REFERENC= 'COBE Ref. Pub. No. 97-A (Greenbelt,MD: NASA/GSFC),' / REFERENC= 'available in electronic form from the NSSDC.' / COMMENT COMMENT COBE specific keywords DATE-BEG= '11/12/89' / date of initial data represented (dd/mm/yy) DATE-END= '21/09/90' / date of final data represented (dd/mm/yy) PIXRESOL= 9 / Quad tree pixel resolution [6, 9] COMMENT COMMENT DIRBE specific keywords PRODUCT = 'SSOD_PALLAS' / Solar System Objects Data for Pallas VERSION = 'Pass 3B ' / Version of Data Reduction Software WAVE1 = '1.25 microns' / nominal wavelength of Band 1 WAVE2 = '2.2 microns' / nominal wavelength of Band 2 WAVE3 = '3.5 microns' / nominal wavelength of Band 3 WAVE4 = '4.9 microns' / nominal wavelength of Band 4 WAVE5 = '12. microns' / nominal wavelength of Band 5 WAVE6 = '25. microns' / nominal wavelength of Band 6 WAVE7 = '60. microns' / nominal wavelength of Band 7 WAVE8 = '100. microns' / nominal wavelength of Band 8 WAVE9 = '140. microns' / nominal wavelength of Band 9 WAVE10 = '240. microns' / nominal wavelength of Band 10 SOLELONG= 'ALL ' / all available solar elongations included APPVEC = 'SEPARATE' / data having different approach vectors COMMENT / are not combined during processing ZLREMOV = F / zodiacal foreground removal indicator COMMENT / if 'T(rue)', a global zodi foreground model COMMENT / has been removed COMMENT / if 'F(alse)', the global zodi foreground model COMMENT / has not been removed COMMENT COMMENT END
Extension Header 2
XTENSION= 'BINTABLE' / Extension type is Binary Table BITPIX = 8 / Binary data NAXIS = 2 / Data are in a table NAXIS1 = 128 / Number of 8 bit bytes in each row NAXIS2 = 61 / Number of rows PCOUNT = 0 / Number of bytes of data following table GCOUNT = 1 / Group count (always 1 for bintable extensions) TFIELDS = 13 / Number of fields (columns) in the table COMMENT COMMENT TIMVERSN= 'OGIP/93-003' / GSFC Office of Guest Investigator Programs COMMENT / (OGIP) memo in which the convention is COMMENT / described COMMENT The times reported in this file are International COMMENT Atomic Time (TAI) seconds elapsed since COMMENT 00:00:00 UTC, 1 January 1981. Time information is COMMENT recorded in a manner consistent with the convention specified COMMENT in OGIP/93-003 with the understanding that time is counted COMMENT in atomic seconds and the origin of time (MJDREF) is quoted COMMENT in ephemeris MJD. TIMESYS = '1981.00 ' / time system (same as IRAS) MJDREFI = 44605 / Integer portion of ephemeris MJD COMMENT / corresponding to 0h UTC 1 Jan 1981 MJDREFF = 0.00059240741 / Fractional portion of ephemeris MJD COMMENT / corresponding to 0h UTC 1 Jan 1981 TIMEUNIT= 's ' / unit for TSTART, TSTOP, TIMEZERO = seconds TSTART = 282185275.611 / observation start time in TIMESYS system TSTOP = 306753235.358 / observation stop time in TIMESYS system COMMENT COMMENT COMMENT COMMENT ------------------------------------------------------------------- COMMENT ******************************************************************* COMMENT -- Solar System Objects Data -- COMMENT ----------- PALLAS ------------ COMMENT COMMENT The Solar System Object Dataset contains flux densities and COMMENT other data pertaining to individual passages of solar system COMMENT objects through the DIRBE field of view during the period of COMMENT cryogenic operation from 11 Dec 1989 to 21 Sept 1990. This file COMMENT contains data for Pallas. It contains one record per object COMMENT passage, listed in order of time of observation. COMMENT COMMENT For data from an object passage to be included in the dataset, COMMENT the object's signal above background in the time-ordered data COMMENT must exceed a source detection threshold for at least two COMMENT detectors. The threshold values are as follows: COMMENT COMMENT Wavelength Detector Threshold COMMENT (microns) (Janskys) COMMENT ---------- -------- --------- COMMENT 1.25 1A 140 COMMENT 2.2 2A 120 COMMENT 3.5 3A 78 COMMENT 4.9 4 96 COMMENT 12 5 130 COMMENT 25 6 270 COMMENT 60 7 380 COMMENT 100 8 590 COMMENT 140 9 40000 COMMENT 240 10 20000 COMMENT COMMENT For regions of the sky with minimal confusion noise, the COMMENT thresholds correspond to signal-to-noise ratios of COMMENT about 20 for detectors 1A-4, 8 for detectors 5-7, and 10 for COMMENT detectors 8-10. Another criterion for inclusion in the dataset COMMENT is that, at the time of the object's closest approach to the center COMMENT of the field of view, its ephemeris position must lie within COMMENT +-10 arcminutes of the DIRBE boresight position in the in-scan COMMENT direction, and within +-18 arcminutes in the cross-scan direction. COMMENT These criteria select against low-quality COMMENT photometric observations. In addition, any passages for which COMMENT the DIRBE boresight position is within 60 arcminutes of a DIRBE COMMENT approved calibration object or another solar system object are COMMENT excluded from the dataset. However, no checking is performed COMMENT for the presence of other objects that could potentially COMMENT contaminate the photometry. COMMENT COMMENT Source photometry is calculated from the time-ordered data by COMMENT (1) extracting a 15-point string of data centered on the object COMMENT passage, (2) fitting a polynomial to the off-source portions of COMMENT the data string to determine a background model, (3) selecting COMMENT a beam profile response template (i.e, response as a function of COMMENT in-scan position) matching the cross-scan position of the COMMENT object passage, and (4) fitting the beam template's height and COMMENT in-scan position to the on-source portion of the COMMENT background-subtracted data string (typically the 3 central data COMMENT points). The beam templates are derived from the normalized COMMENT beam profile maps dataset (see DIRBE Explanatory Supplement). COMMENT Source photometry was sometimes considered to be unreliable COMMENT for a given detector because of large residuals about the COMMENT background fit or beam template fit, or because the object COMMENT passage was close to the cross-scan 'edge' of the beam profile COMMENT where pointing error can result in a large uncertainty in the COMMENT adopted beam template. In such cases, a sentinel value of COMMENT -16000. is listed for the fields Photomet and PhotErr for that COMMENT detector. COMMENT COMMENT ******************************************************************* COMMENT ------------------------------------------------------------------- COMMENT =================================================================== COMMENT Coordinate Information: COMMENT =================================================================== COMMENT ------------------------------------------------------------------- COMMENT Time of central passage. COMMENT Time of the object's closest approach to the center of COMMENT the field of view, in International Atomic Time (TAI) COMMENT seconds elapsed since 01-JAN-1981:00:00:00.000 UTC. TTYPE1 = 'Time ' / pipeline fieldname = Time TUNIT1 = 's ' / TFORM1 = '1D ' / COMMENT ------------------------------------------------------------------- COMMENT DIRBE Pixel number (resolution 9) COMMENT DIRBE pixel number in which the object is COMMENT located at the time of central passage. TTYPE2 = 'Pixel_No' / pipeline fieldname = PIXEL_NO TUNIT2 = ' ' / TFORM2 = '1J ' / COMMENT ------------------------------------------------------------------- COMMENT Right Ascension of Object at the time of central COMMENT passage, epoch 1950 COMMENT range = [0, 24) hours TTYPE3 = 'RA1950 ' / pipeline fieldname = ra_1950 TUNIT3 = 'hr ' / TFORM3 = '1E ' / COMMENT ------------------------------------------------------------------- COMMENT Declination of Object at the time of central COMMENT passage, epoch 1950 COMMENT range = [-90, 90] degrees TTYPE4 = 'DEC1950 ' / pipeline fieldname = dec_1950 TUNIT4 = 'deg ' / TFORM4 = '1E ' / COMMENT ------------------------------------------------------------------- COMMENT Galactic Longitude of Object at the time of central COMMENT passage COMMENT range = [0, 360) degrees TTYPE5 = 'GalLon ' / pipeline fieldname = gal_longitude TUNIT5 = 'deg ' / TFORM5 = '1E ' / COMMENT ------------------------------------------------------------------- COMMENT Galactic Latitude of Object at the time of central COMMENT passage COMMENT range = [-90, 90] degrees TTYPE6 = 'GalLat ' / pipeline fieldname = gal_latitude TUNIT6 = 'deg ' / TFORM6 = '1E ' / COMMENT ------------------------------------------------------------------- COMMENT Ecliptic Longitude of Object at the time of central COMMENT passage, epoch 2000 COMMENT range = [0, 360) degrees TTYPE7 = 'EclLon ' / pipeline fieldname = ecl_longitude TUNIT7 = 'deg ' / TFORM7 = '1E ' / COMMENT ------------------------------------------------------------------- COMMENT Ecliptic Latitude of Object at the time of central COMMENT passage, epoch 2000 COMMENT range = [-90, 90] degrees TTYPE8 = 'EclLat ' / pipeline fieldname = ecl_latitude TUNIT8 = 'deg ' / TFORM8 = '1E ' / COMMENT ------------------------------------------------------------------- COMMENT Solar elongation of the object at the time of COMMENT central passage, i.e., angle between the vector COMMENT from the spacecraft to the center of the object and COMMENT the vector from the spacecraft to the center of the Sun. COMMENT Nominal range = [64, 124] degrees TTYPE9 = 'SolElong' / pipeline fieldname = elongation TUNIT9 = 'deg ' / TFORM9 = '1E ' / COMMENT ------------------------------------------------------------------- COMMENT Geocentric distance of the object at the time of COMMENT central passage, in astronomical units. TTYPE10 = 'Distance' / pipeline fieldname = distance TUNIT10 = 'AU ' / TFORM10 = '1E ' / COMMENT ------------------------------------------------------------------- COMMENT Heliocentric distance of the object at the time of COMMENT central passage, in astronomical units. TTYPE11 = 'HelioDist' / pipeline fieldname = heliodist TUNIT11 = 'AU ' / TFORM11 = '1E ' / COMMENT ------------------------------------------------------------------- COMMENT =================================================================== COMMENT Photometric Information: COMMENT =================================================================== COMMENT ------------------------------------------------------------------- COMMENT Source Photometry COMMENT Background-subtracted flux density of the object, F(nu), COMMENT in units of Jy. Presented for the total intensity COMMENT channels in increasing wavelength order from COMMENT 1.25 to 240 microns. Flux density is quoted COMMENT at the nominal wavelength for a source with assumed COMMENT energy distribution nu*F(nu) = constant -- i.e., COMMENT a color correction is required if the source COMMENT spectrum differs from the assumed distribution. COMMENT This field is set to -16000. for wavelengths COMMENT for which photometry is not provided. TTYPE12 = 'Photomet' / pipeline fieldname = Photometry TUNIT12 = 'Jy ' / TFORM12 = '10E ' / TDIM12 = '(10) ' / COMMENT ------------------------------------------------------------------- COMMENT Photometric Error COMMENT Estimated error of the flux density quoted in the COMMENT Photometry field, in Jy, listed in order of increasing COMMENT wavelength. Calculated as the quadrature sum of COMMENT (1) the rms deviation of the time-ordered data from COMMENT the baseline and beam template fit, and (2) the error COMMENT due to the uncertainty in beam template resulting COMMENT from cross-scan pointing error. COMMENT This field is set to -16000. for wavelengths COMMENT for which photometry is not provided. TTYPE13 = 'PhotErr ' / pipeline fieldname = photerr TUNIT13 = 'Jy ' / TFORM13 = '10E ' / TDIM13 = '(10) ' / COMMENT ------------------------------------------------------------------- END
