iraf.net

hi there,I have a set of GMOS (Gemini) longslit spectra. I reduced them using Gemini package, up to wavelength calibration (gstransform). From now on I want to use noao package to extract the apertures (apall). Because gemini fits has a specific format, i did:imcopy gmos_image[sci,1,inherit] imageand tried to extract the spectrum from 'image'. apall works nicely, but in the end it complains Warning: coordinate system ignored (rotated?). Using pixel coordinates.and thus the extracted spectrum is not wavelength calibrated.
does any one know how to fix this?
i will also post to gemini helpdesk, but they usually are not quick in answering...below follows the image header.thx a lot, paula

ntgsN20041010S0032[3108,2304][real]: M32
No bad pixels, min=0., max=0. (old)
Line storage mode, physdim [3108,2304], length of user area 8505 s.u.
Created Tue 16:32:09 03-Oct-2006, Last modified Tue 16:32:09 03-Oct-2006
Pixel file "ntgsN20041010S0032.fits" [ok][/size]
EXTEND = F / File may contain extensions
ORIGIN = 'NOAO-IRAF FITS Image Kernel July 2003' / FITS file DATE = '2006-10-03T19:32:09' / Date FITS file was generated
IRAF-TLM= '16:32:09 (03/10/2006)' / Time of last modification
OBJECT = 'M32 ' / Name of the object observed
INSTRUME= 'GMOS-N ' / Instrument used to acquire data
OBSTYPE = 'OBJECT ' / Observation type
GEMPRGID= 'GN-2004B-Q-74' / Gemini programme ID
OBSID = 'GN-2004B-Q-74-2' / Observation ID / Data label
DATALAB = 'GN-2004B-Q-74-2-002' / DHS data label
OBSERVER= 'R.Johnson' / Observer
OBSERVAT= 'Gemini-North' / Name of telescope (Gemini-North|Gemini-South)
TELESCOP= 'Gemini-North' / Gemini-North
PARALLAX= 0. / Parallax of Target
RADVEL = 0. / Heliocentric Radial Velocity
EPOCH = 2000. / Epoch for Target coordinates
EQUINOX = 2000. / Equinox of coordinate system
TRKEQUIN= 2000. / Tracking equinox
SSA = 'J.Bodnarik' / SSA
RA = 10.67916667 / Right Ascension
DEC = 40.8525 / Declination of Target
ELEVATIO= 66.2085 / Current Elevation
AZIMUTH = 335.079754166667 / Current Azimuth
CRPA = 16.8689574716234 / Current Cass Rotator Position Angle
HA = '+00:52:03.12' / Telescope hour angle
LT = '00:39:26.1' / Local time at start of observation
TRKFRAME= ' ' / Tracking co-ordinate
DECTRACK= 0. / Differential tracking rate Dec
TRKEPOCH= 0. / Differential tracking reference epoch
RATRACK = 0. / Differential tracking rate RA
FRAME = 'FK5 ' / Target coordinate system
PMDEC = 0. / Proper Motion in Declination
PMRA = 0. / Proper Motion in RA
WAVELENG= 6800. / Effective Target Wavelength
RAWIQ = '70-percentile' / Raw Image Quality
RAWCC = '70-percentile' / Raw Cloud Cover
RAWWV = 'Any ' / Raw Water Vapour/Transparency
RAWBG = '50-percentile' / Raw Background
RAWPIREQ= 'YES ' / PI Requirements Met
RAWGEMQA= 'USABLE ' / Gemini Quality Assessment
CGUIDMOD= 'Basic ' / Carousel Mode
UT = '10:39:26.1' / UT at observation start
M2BAFFLE= 'VISIBLE ' / Position of M2 baffle
M2CENBAF= 'CLOSED ' / Position of M2 central hole baffle
ST = '01:35:02.4' / Sidereal time at the start of the exposure
XOFFSET = 1.19000000349 / Telescope offset in x in arcsec
YOFFSET = 0. / Telescope offset in y in arcsec
RAOFFSET= 1.14858717259 / Telescope offset in RA in arcsec
DECOFFSE= -0.311203334287 / Telescope offset in DEC in arcsec
PA = 165. / Sky Position Angle at start of exposure
SFRT2 = 178.766 / Science fold rotation angle (degrees)
SFTILT = 44.96 / Science fold tilt angle (degrees)
SFLINEAR= -2. / Science fold linear position (mm)
AOFOLD = 'park-pos.' / AO Pick-Off Mirror Position
OIARA = 10.75379167 / RA of OIWFS guide star
OIARV = 0. / OIWFS Heliocentric Radial Velocity
OIAWAVEL= 6500. / OIWFS Effective Target Wavelength
OIADEC = 40.82497222 / Declination of OIWFS guide star
OIAEPOCH= 2000. / Epoch for OIWFS guide star coordinates
OIAEQUIN= 2000. / Equinox for OIWFS guide star coordinates
OIAFRAME= 'FK5 ' / OIWFS Target co-ordinate system
OIAOBJEC= 'GSC0280101056' / Object Name for OIWFS, Chop A
OIAPMDEC= 0. / OIWFS Proper Motion in Declination
OIAPMRA = 0. / OIWFS Proper Motion in RA
OIAPARAL= 0. / OIWFS Parallax of Target
HUMIDITY= 10. / The Relative Humidity (fraction, 0..101).
TAMBIENT= 1.9 / The ambient temp (C).
TAMBIEN2= 35.42 / The ambient temp (F).
PRESSURE= 462.17248 / The atmospheric pressure (mm Hg).
PRESSUR2= 61600. / The atmospheric pressure (Pa).
DEWPOINT= -27.3 / The dew point (C).
DEWPOIN2= -17.14 / The dew point (F).
WINDSPEE= 2.4 / The wind speed (m/s).
WINDSPE2= 5.3688 / The wind speed (mph).
WINDDIRE= 334. / The wind direction (degrees).
INPORT = 5 / Number of ISS port where GMOS was located
GMOSCC = 'GMOS-N (V4-6)' / GMOS components controller s/w
CONID = 'GMOS v8.0' / Detector controller ID
DETECTOR= 'GMOS + Red1' / Detector name
DEWAR = 'Cryostat A' / Dewar name
DEW-TEMP= -119.906103286385 / Dewar temperature (Celsius)
DETSIZE = '[1:6144,1:4644]' / Detector size
NCCDS = 3 / Number of CCD chips
NAMPS = 1 / Number of amplifiers
SHUTTER = 'OPEN ' / Shutter state during observation
AMPINTEG= 5000 / Amplifier integration time
OBSEPOCH= 2004.77465863844 / Epoch at start of exposure
TIMESYS = 'UT1 ' / Time system used
DATE-OBS= '2004-10-10' / UT Date of observation (YYYY-MM-DD)
TIME-OBS= '10:40:02.3' / Time of observation
GMOSTHT = 'GOOD ' / Shutter health
NSUBEXP = 1 / Number of sub exposures
UTSTART = '10:40:02.3' / UT at observation start
UTEND = '10:40:32.3' / UT at observation end
EXPTIME = 30.0001728534698 / Exposure time in seconds
ELAPSED = 30.0001728534698 / Elapsed observation time in seconds
DARKTIME= 66.9165539741516 / Dark current integration in seconds
MASKID = 10005353 / Mask/IFU barcode
MASKNAME= '0.75arcsec' / Mask name
MASKTYP = 1 / Mask/IFU type (0=none/-1=IFU/1=mask)
MASKLOC = 0 / Mask/IFU location (-1=unknown/0=FP/1=cassette)
FILTER1 = 'open1-6 ' / Filter 1 name
FILTID1 = 20000018 / Filter 1 barcode
FILTER2 = 'open2-8 ' / Filter 2 name
FILTID2 = 20000008 / Filter 2 barcode
GRATING = 'R400+_G5305' / Grating name
GRATID = 30000006 / Grating barcode
GRWLEN = 680. / Grating central wavelength (nm)
GRORDER = 1 / Grating order
GRTILT = 56.3696 / Grating tilt angle (degrees)
GRSTEP = 6033.8454 / Requested grating motor step position
DTAX = 84.4 / Detector translation X position (microns)
DTAY = 90.4 / Detector translation Y position (microns)
DTAZ = 2374. / Detector translation Z position (microns)
DTAZST = 2374. / Focus at observation start (microns)
DTAZEN = 2374. / Focus at observation end (microns)
DTAZME = 0. / Mean focus during observation (microns)
DTMODE = 'FOLLOW-XY' / Detector translation stage mode
ADCMODE = ' ' / ADC mode
GMOSDC = 'GMOS DC ' / GMOS detector controller s/w
DETTYPE = 'SDSU II CCD' / Detector array type
DETID = 'EEV9273-16-03EEV9273-20-04EEV9273-20-03' / Chip IDs
EXPOSURE= 30. / Requested exposure time in seconds
ADCUSED = 1 / ADC used? (0=yes/1=no)
DETNROI = 1 / No. regions of interest
ADCENPST= 0. / Start entrance prism angle of ADC
ADCENPEN= 0. / End entrance prism angle of ADC
ADCENPME= 0. / Mean entrance prism angle of ADC
ADCEXPST= 0. / Start exit prism angle of ADC
ADCEXPEN= 0. / End exit prism angle of ADC
ADCEXPME= 0. / Mean exit prism angle of ADC
ADCWLEN1= 0. / Lower wavelength for ADC calculation
ADCWLEN2= 0. / Upper wavelength for ADC calculation
DETRO1X = 1 / ROI 1 X start
DETRO1XS= 3072 / ROI 1 X size
DETRO1Y = 1 / ROI 1 Y start
DETRO1YS= 2304 / ROI 1 Y size
AIRMASS = 1.093 / Mean airmass for the observation
AMSTART = 1.093 / Airmass at start of exposure
AMEND = 1.094 / Airmass at end of exposure
RELEASE = '2006-04-10 ' / End of proprietary period YYYY-MM-DD
NSCIEXT = 1 /1 /3 / Number of science extensions
PIXSCALE= 0.1454 / Pixel scale in Y in arcsec/pixel
NEXTEND = 2 /1 /2 /1 /4 / Number of extensions
OBSMODE = 'LONGSLIT ' / Observing mode (IMAGE|IFU|MOS|LONGSLIT)
GPREPARE= 'Tue Mar 7 18:45:10 UTC 2006' / Time stamp for GPREPARE
GEM-TLM = 'Wed Mar 8 17:21:23 UTC 2006' / Last modification with GEMINI
TRIMMED = 'yes ' / Overscan section trimmed
BIASIM = 'N20041006S0055_bias' / Bias image used by GIREDUCE
FLATIM = 'N20041010S0031_flat' / Flat field used by GIREDUCE
GIREDUCE= 'Tue Mar 7 18:45:14 UTC 2006' / Time stamp for GIREDUCE
GSCRREJ = 'Tue Mar 7 18:46:17 UTC 2006' / Time stamp for GSCRREJ
GSCRRES = 4.5 / GSCRREJ equivalent instrumental FWHM
GSCRTHRE= 10. / GSCRREJ sigma rejection threshold
CD1_2 = -1.04631447062649E-05 / WCS matrix element 1 2
CD2_1 = 1.04314816840428E-05 / WCS matrix element 2 1
GMOSAIC = 'Tue Mar 7 18:46:20 UTC 2006' / Time stamp for GMOSAIC
GMSINTER= 'linear ' / Interpolant used by GMOSAIC
GSAPPWAV= 'Tue Mar 7 18:46:21 UTC 2006' / Time stamp for GSAPPWAVE
GSREDUCE= 'Tue Mar 7 18:46:21 UTC 2006' / Time stamp for GSREDUCE
WMEF = 'Wed Mar 8 17:21:23 UTC 2006'
GSTRANSF= 'Wed Mar 8 17:21:23 UTC 2006' / Time stamp for GSTRANSFORM
CTYPE1 = 'LINEAR ' / R.A. in tangent plane projection
CTYPE2 = 'LINEAR ' / DEC. in tangent plane projection
CRPIX1 = 1. / Ref pix of axis 1
CRPIX2 = 1. / Ref pix of axis 2
CRVAL1 = 4696.5439453125 / RA at Ref pix in decimal degrees
CRVAL2 = 1. / DEC at Ref pix in decimal degrees
CD1_1 = 1.36486196517944 / WCS matrix element 1 1
CD2_2 = 1. / WCS matrix element 2 2
CCDSUM = '2 2 ' / CCD sum
GAIN = 1. / Amplifier gain
RDNOISE = 3.3 / Readout noise
WAT0_001= 'system=world'
WAT2_001= 'wtype=linear'
DISPAXIS= 1 /1 / Dispersion axis
DCLOG1 = 'Transform'
DC-FLAG = 0
WCSDIM = 2
CDELT1 = 1.36486196517944
CDELT2 = 1.
LTM1_1 = 1.
LTM2_2 = 1.
WAT1_001= 'wtype=linear label=Wavelength units=angstroms'
WAVTRAN = 'gsN20041010S0144_001' / Name of wavelength transformation

Hi Paula,The problem is due to the presence of the diagonal elements of the CD matrix. Initially the GMOS data had an RA/DEC system. After processing it is creating a longslit system (wavelength and spatial) where the axes are expected to be independent. I'm not sure if the fact the CD1_2 and CD2_1 keywords are not removed is a problem in the gemini package or the NOAO/IRAF task which it calls. The solution is to use HEDIT to remove CD1_2 and CD2_1.Yours,
Frank Valdes