Re: Fits Headers Again

[Doug Welch <welch@physics.mcmaster.ca>]

Hi Tom,

It needs an EPOCH or an EQUINOX (or both).

Cheers,
Doug

On Sat, 10 Mar 2001, Tom Droege wrote:

> Below is some stuff copied (now directly) out of TN-67.  My plan is to make 
> two files.  One is the fixed stuff and one varies run by run.  My question 
> is, what is a fits extension?   Is it everything after the:  EXTEND 
> =                      T/ line below or is it something else?
> 
> Tom Droege
> 
> 
> Recommendations:
> ·       Switch RA and DEC axis.
> ·       CTYPE1 and CTYPE2 must read 'RA---TAN' and 'DEC--TAN', respectively.
> ·       EXPOSURE keyword must be present, with correct exposure time in 
> secomds.
> ·       It's better to use reference pixels in the middle of image: CRPIX1, 
> CRPIX2=1024.
> ·       CDELT1 and CDELT2 are missing now, they must contain pixel 
> increment at the reference pixel. In simpler terms, pixel size with 
> possible negative sign if coordinate is decreasing with increasing pixel 
> coordinates. Size is expressed in decimal degrees.
> ·       Keyword IMAGETYP with possible values 'object', 'dark', 'flat' and 
> 'zero' should be included if IRAF proceessing of images will be used.
> ·       Change DATE-OBS to include time as well, not only date.
> ·       Inclusion of the following keywords may be useful
> ·       RDNOISE in electrons.
> ·       GAIN in electrons/ADU.
> ·       CCD-TEMP or CAMTEMP with temperature in degrees Celsius.
> ·       AIRMASS
> Example of enhanced header after star matching (image H3R1659-826.fts):
> SIMPLE  =                    T / file does conform to FITS standard
> BITPIX  =                   16 / number of bits per data pixel
> NAXIS   =                    2 / number of data axes
> NAXIS1  =                 2043 / length of data axis 1
> NAXIS2  =                 2037 / length of data axis 2
> EXTEND  =                    T / FITS dataset may contain extensions
> COMMENT   FITS (Flexible Image Transport System) format defined in Astronomy an
> 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.
> CTYPE1  = 'RA---TAN'           / Inserted by fitsblink
> CRVAL1  =   2.263508539420E+02 / Inserted by fitsblink
> CRPIX1  =   1.021500000000E+03 / Inserted by fitsblink
> CROTA1  =   8.974035779811E+01 / Inserted by fitsblink
> CTYPE2  = 'DEC--TAN'           / Inserted by fitsblink
> CRVAL2  =   1.723629532873E+00 / Inserted by fitsblink
> CRPIX2  =   1.018500000000E+03 / Inserted by fitsblink
> CROTA2  =   8.974035779811E+01 / Inserted by fitsblink
> BSCALE  =                   1.
> BZERO   =               32768.
> LATITUDE=                  42.
> LONGITUD=                 -88.
> FILTER  = 'V       '
> DATE    = '2000-04-25'
> DATE-OBS= '2000-04-25'
> UT      = '07:49:52.00'
> TIMESYS = 'UT      '
> COMMENT    This file produced by TASS RawToFITS program  Version 1.1
> CDELT1  =   2.150392161597E-03 / Inserted by fitsblink
> CDELT2  =   2.150050490463E-03 / Inserted by fitsblink
> IMAGETYP= 'object  '           / insert_keywords
> EXPOSURE=         1.500000E+01 / insert_keywords
> EXPTIME =         1.500000E+01 / insert_keywords
> MATCHED =                    T / Inserted by fitsblink
> END
> 
> 

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 Douglas L Welch     | Office/voicemail (905) 525-9140 x23186  
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