FITS header info

[bkm2304 (Richard Brown)]

Hello all,

When I read the header information in my FITS files in Astrometrica, I cannot see the dec or ra numbers. In Astrometrica and CCDOps I can't see where to make this an inclusion in the header. Can anyone help me.....please......pretty please.....

Richard the downcast aka Richard the frustrated

[Geoff45 (Geoff)]

I use Maxim, so this is only a guess. The info about position has to come from the mount's goto system, so there will have to be an item something like "connect telescope" in your image acquisition software, probably requiring an RS232 serial cable, so that the computer and the mount can talk to each other.
Geoff

[Karls48 (Karl)]

Geoff is right. I do use Maxim too. You need to run dome Planetarium software that connect to your mount and also connect to Maxim DL. Planetarium software passes mount coordinates (that include all your mount pointing errors) to Maxim and it calls PinPoint to do Plate solve based on star catalogue you have chosen. PinPoint then writes correct coordinates to FITS header.
If your mount is not connected to computer you can do it as post processing manually. You need to know approximate centre coordinates of your image, type it in PinPoint or similar Plate solving software and it will do Plate solve and write it in the image FITS header. But it is time consuming.

[Terry B]

The way around it is to use plate solving software to add the data to the header.
I use Elbrus (free)
http://tech.groups.yahoo.com/group/StarLocatorElbrus/
It will solve the image as long as you can tell it the pixel/ arcsec and the centre of the image within 5deg. There are methods for it to work out the pixel size for you as long as you can identify 3 stars in your image and give their guide GSC number.

[Barrykgerdes]

Hi
The fts header contains 2880 bytes set aside for information on the picture. The first line of 80 characters. 31st character gives the format for the data. I think there are 25 standard lines for data but there is also a section where you can add another 11 lines of your own data.
RA and Dec are not standard entries as far as I can make out.

The program that you are using to write the .fts file will be formated to use some part of the data area that it can address but it will not necessarily be compatable with all .fts files.

I wrote a little program to read the fts header to get this info so it may not suit all fts files. It could als be adapted to write a fts header.

Barry

[Geoff45 (Geoff)]

Originally Posted by Barrykgerdes

Hi

RA and Dec are not standard entries as far as I can make out.


Barry

But the image acquisition software should allow you to put in this info

[mithrandir (Andrew)]

Originally Posted by Barrykgerdes

Hi
RA and Dec are not standard entries as far as I can make out.

RA and DEC do appear to be optional. These are from a DSS image:

EPOCH = 1.9519078369141E+03 /Epoch of plate
PLTRAH = 6 /Plate center RA
PLTRAM = 56 /
PLTRAS = 5.4442400000000E+00 /
PLTDECSN= '+ ' /Plate center Dec
PLTDECD = 11 /
PLTDECM = 49 /
PLTDECS = 5.6906700000000E+00 /

OBJCTRA = '06 56 26.000 ' /Object Right Ascension (J2000)
OBJCTDEC= '+11 53 53.00 ' /Object Declination (J2000)

[Barrykgerdes]

and Here is some data from another DSS image (ic2944):

SIMPLE = T /FITS HEADER
BITPIX = 16 /NO.BITS PER PIXEL
NAXIS = 2 /NO.DIMENSIONS
NAXIS1 = 2119 /LENGTH X AXIS
NAXIS2 = 2119 /LENGTH Y AXIS
DATE = '10/12/10 ' /DATE OF FITS FILE CREATION
ORIGIN = 'CASB -- STSCI ' /ORIGIN OF FITS IMAGE
PLTLABEL= 'V 11778 ' /OBSERVATORY PLATE LABEL
PLATEID = '06AG ' /GSSS PLATE ID
REGION = 'XV094 ' /GSSS REGION NAME
DATE-OBS= '06/04/87 ' /UT DATE OF OBSERVATION
UT = '11:32:00.00 ' /UT TIME OF OBSERVATION
PLTRAH = 11 /PLATE CENTER RA
PLTRAM = 46 /
PLTRAS = 2.4452550000000E+01 /
PLTDECSN= '- ' /PLATE CENTER DEC
PLTDECD = 65 /
PLTDECM = 16 /
PLTDECS = 4.0241680000000E+01 /
EQUINOX = 2.0000000000000E+03 /JULIAN REFERENCE FRAME EQUINOX
EXPOSURE= 4.0000000000000E+00 /EXPOSURE TIME MINUTES
BANDPASS= 6 /GSSS BANDPASS CODE
PLTGRADE= 1 /PLATE GRADE
PLTSCALE= 6.7200000000000E+01 /PLATE SCALE ARCSEC PER MM
SITELAT = '-31:16:24.00 ' /LATITUDE OF OBSERVATORY
SITELONG= '+149:03:42.00 ' /LONGITUDE OF OBSERVATORY
TELESCOP= 'UK SCHMIDT (NEW OPTICS)' /TELESCOPE WHERE PLATE TAKEN
CNPIX1 = 8464 /X CORNER (PIXELS)
CNPIX2 = 10736 /Y CORNER
DATATYPE= 'INTEGER*2 ' /TYPE OF DATA
SCANIMG = 'XV094_06AG_00_00.PIM' /NAME OF ORIGINAL SCAN
SCANNUM = 0 /IDENTIFIES SCAN OF THE PLATE
DCHOPPED= F /IMAGE REPAIRED FOR CHOPPING EFFECTS
DSHEARED= F /IMAGE REPAIRED FOR SHEARING EFFECTS
DSCNDNUM= 0 /IDENTIFIES DESCENDANT OF PLATE SCAN IMAGE
XPIXELSZ= 2.5284450000000E+01 /X PIXEL SIZE MICRONS

and from a Meade image with a pictor 208 CCD (M83)

SIMPLE = T / BASIC FORMAT
BITPIX = 8 / 0..255, B..W
NAXIS = 2 / NUMBER OF AXES
NAXIS1 = 324 / PIXELS PER ROW
NAXIS2 = 242 / ROWS
BSCALE = 1.000000
BZERO = 0.000000
OBJECT = 'M3 Lx200 8: @f3.44 4x120sec '
ORIGIN = 'Little Blair Valley
DATE = '1998-04-15T00:00:00'
DATE-OBS= '1998-04-15T00:16:57'
TIME = '00:16:57 '
EXPOSURE= '120.00 secs '
TEMPERAT= 0.00
INSTRUME= 'Pictor 208 '
TELESCOP= 'LX200 8" @f3.444 '
OBSERVER= ' '
COMMENT 'M63 Lx200 8: @f3.44 4x120sec '
DATAMIN = 2.000000
DATAMAX = 118.000000
OBSERVAT= ' '
TIME-OBS= '00:16:57'
EXPTIME = 120.000000
DISPMIN = 17.000000
DISPMAX = 58.000000
END

So you can see the variation in data content.

Here is the program I read this with (without the test fits files, too big)

Barry

[bkm2304 (Richard Brown)]

Thanks, everyone. Very informative!

Richard