The image atlas consists of a series of 512x1024 pixel (1"/pixel) images for each scan, one FITS format file per band for each image. The naming convention is as follows: BiSSSIIII.fits where: B - the wavelength band (j, h, or k) SSS - the scan number IIII - the image number within the scan (named for the closest frame to the image center) The following table gives an example of the FITS image header format. The first line is included to show the column alignment, and is not part of the FITS header. 1234567890123456789012345678901234567890123456789012345678901234567890123456789 BITPIX = -32 / Data Values are IEEE 32 Bit Reals NAXIS = 2 / # of Axes NAXIS1 = 512 / Number of Columns in Image NAXIS2 = 1024 / Number of Lines in Image ORDATE = '980427 ' / Observation Ref Date (yymmdd) DAYNUM = '0423 ' / Observation Day Num FN_PRFX = 'j0423049' / .rdo and .par filename prefix TYPE = 'sci ' / Scan type: dar flt sci cal tst SCANNO = 49 / Scan Number SCANDIR = 'n ' / Scan Direction: n, s, - COMMENT (OV) STRIP_ID= 308049 / Strip ID (OV) POSITNID= 's121722 ' / Position ID (OV) ORIGIN = '2MASS ' / 2MASS Survey Camera CTYPE1 = 'RA---SIN' / Orthographic Projection CTYPE2 = 'DEC--SIN' / Orthographic Projection CRPIX1 = 256.5 / Column Coordinate of Grid Center CRPIX2 = 512.5 / Line Coordinate of Grid Center CRVAL1 = 260.74079 / RA at Frame Center, J2000 (deg) CRVAL2 = -14.36022188 / Dec at Frame Center, J2000 (deg) CROTA2 = 0.01315398872 / Image Twist +AXIS2 W of N, J2000 (deg) CDELT1 = -0.0002777777845 / Axis 1 Pixel Size (degs) CDELT2 = 0.0002777777845 / Axis 2 Pixel Size (degs) USXREF = -256.5 / U-scan X at Grid (0,0) USYREF = 12766. / U-scan Y at Grid (0,0) SKYVAL = 146.9015198 / GFIND Sky Estimate (Image DN) SKYSIG = 0.8133392334 / Grid Noise Estimate (Image DN) MAGZP = 20.7872 / Calibrated zero point from CALMAN CALID = 'y lf 0 Oct 27 1998 '/ Calibration descriptors from CALMAN SEESH = 1.0400 / Seeing shape parameter from SEEMAN DXFS = 0.5750201344 / Cross-scan Frame Step (arcsec) DYFS = 82.28955841 / In-scan Frame Step (arcsec) PIXNAM = 'nl.pixphot - v 980423c' QT0227 = 145.4931641 / 2.27 Percentile (Image DN) QT0668 = 145.8517761 / 6.68 Percentile (Image DN) QT1586 = 146.2314911 / 15.86 Percentile (Image DN) QT3085 = 146.6295166 / 30.85 Percentile (Image DN) QT5000 = 147.0448303 / 50.00 Percentile (Image DN) QT6914 = 147.4942932 / 69.14 Percentile (Image DN) QT8413 = 148.031723 / 84.13 Percentile (Image DN) QT9331 = 148.8986664 / 93.31 Percentile (Image DN) QT9772 = 152.4276581 / 97.72 Percentile (Image DN) BASE = 6 / Pixel Dwell (microsec) WAVEF_P = '2massn.scn' / Secondary waveform data file TIMER0 = 52 / Read1 time (millisecs) TIMER1 = 1298 / Read2-Read1 time (millisecs) TIMER2 = 51 / Secondary settling time (millisecs) ICSVERSN= '980324 ' / ICS script pgm Version (yymmdd) SCHEDVER= '980416 ' / Scheduler pgm Version (yymmdd) SCRIPTFN= 'survey.sct' / Script template filename SCRPTVER= '980223 ' / Script template filename Versn (yymmdd) UT_OFF1 = 7.427007299270E-01 / UT Offset (IC),SOS to frm#1 Cntr (secs) XS_OFF1 = 7.500000000000E-01 / X-Scan Offset (IN),SOS to f#1 RA Cntr (ASec) IS_OFF1 = 3.745100000000E+02 / In-Scan Offset (IN),SOS to f#1 Dec Cntr(ASec) XS_OFF2 = 1.230000000000E+00 / X-Scan Offset(IN),EOS to End Frm RA Ctr(ASec) IS_OFF2 = -1.149400000000E+02 / In-Scan Offset(IN),EOS to End Frm Dec Ctr(AS) FOCUS = 1045 / Focus Setting NUMFRMS = 274 / Total Number of Frames in this Scan SKIPRDOS= 0 / Total Number of SOS junk RDOs skipped (IC) TELNAME = 'CTIO ' / Telescope -30.165/+70.815 lat/lon degs FILTER = 'j ' / Band: j, h, k UT_DATE = '980427 ' / UT Date of Frame (IC) (yymmdd) UT = '06:33:55.89' / Time of Frame (IC) (sxgsml) AMASS_FC= 1.08769238E+00 / Airmass (aprox) at this Frame (IC) (unitless) GRP2_SOS= 'SOS ' / Bgn Group#2 .par params at SOS DATE_SOS= '980427 ' / Date at SOS (yymmdd) EQUINOX = 2.000000000000E+03 / Equinox at SOS AM_SOS = 1.07000005E+00 / Airmass at SOS (unitless) ZD_SOS = 2.10000000E+01 / Zenith Distance at SOS (degs) HA_SOS = '-01:15:58.00' / Hour Angle at SOS (sxgsml) UT_SOS = '06:29:56.00' / Scan Reference UT (SOS) (sxgsml) ST_SOS = '16:06:53.00' / Sidereal time at SOS (sxgsml) RA_SOS = '17:22:57.61' / Scan Reference RA at SOS ,epoch 2000 (sxgsml) DEC_SOS = '-18:09:09.9' / Scan Reference Dec at SOS,epoch 2000 (sxgsml) WSPD_SOS= 0 / Wind Speed at SOS, see WARNING below WDIR_SOS= 0 / Wind Direction at SOS, see WARNING below HUM_SOS = 62 / Humidity at SOS, 0-100% SEE_SOS = 0.00000000E+00 / Seeing at SOS, see WARNING below BAR_SOS = 2.97000008E+01 / Barometer at SOS (inches of Hg) AIRT_SOS= 4.19999981E+00 / Air temperature at SOS, degs Celsius TELT_SOS= 4.59999990E+00 / Telescope Temp at SOS, degs Celsius ARYT_SOS= -1.90000000E+02 / Temperature of array, see WARNING below GRP2_EOS= 'EOS ' / Bgn Group#2 .par params at EOS DATE_EOS= '980427 ' / Date at EOS (yymmdd) AM_EOS = 1.10000002E+00 / Airmass at EOS (unitless) ZD_EOS = 2.42999992E+01 / Zenith Distance at EOS (degs) HA_EOS = '-01:09:10.00' / Hour Angle at EOS (sxgsml) UT_EOS = '06:36:43.00' / UT at EOS (sxgsml) ST_EOS = '16:13:41.00' / ST at EOS (sxgsml) RA_EOS = '17:22:57.40' / RA at EOS, epoch 2000 (sxgsml) DEC_EOS = '-11:45:55.9' / Dec at EOS, epoch 2000 (sxgsml) WSPD_EOS= 0 / Wind Speed at SOS, see WARNING below WDIR_EOS= 0 / Wind Direction at EOS, see WARNING below HUM_EOS = 65 / Humidity at EOS, 0-100% SEE_EOS = 0.00000000E+00 / Seeing at EOS, see WARNING below BAR_EOS = 2.97000008E+01 / Barometer at EOS (inches of Hg) AIRT_EOS= 4.00000000E+00 / Air temperature at EOS, degs Celsius TELT_EOS= 4.59999990E+00 / Telescope Temp at EOS, degs Celsius ARYT_EOS= -1.90000000E+02 / Temperature of array, see WARNING below COMMENT *** WARNING *** indicated parameter not measured, dummy only COMMENT src keys: (IK)=IPAC Konstant; (IC)=IPAC cmptd; (IN)=IPAC namelist COMMENT (OV)=Obsrvtry .par file variable COMMENT Group 2 parms are ALL from the Obs .par file COMMENT non-Group 2 parms w/o (xx) are usually fm Obs RF_NLID = 'norot sat s 980730' / Rdframe namelist version id HISTORY * Rdframe version= 980423 jhw. Bgn Xeq = 98-10-26 18:47:55 HISTORY * DFlat vsn1.95 980924 Run on 10/26/98 at 18:43:58 HISTORY > Image Created by pixphot - version 980709c HISTORY > Gene Kopan IPAC/ Caltech