http://astroimagej.170.s1.nabble.com/WCS-alignment-tp19p22.html
Hi Russ,
Thanks for the information. The radio image uses SIN
projection for RA and DEC (see CTYPE1 and CTYPE2 in the header) so
we are good there. However, the it has 4 axes (RA, DEC, FREQ,
STOKES) and AIJ can currently only deal with 2 axes (RA and DEC).
The best possibility here is that I might be able (not sure) to
ignore the FREQ and STOKES axes if you are not using those.
I don't see any WCS info in the header for the optical image
header you sent. It looks like the image was written by MaximDL,
and I don't see the usual headers that MaximDL adds after a "plate
solve" has been ran on the image. I believe Maxim uses a program
called pinpoint to do do the plate solve work.
Do you have an installation of DS9 available to you? If so,
when you open the optical image in DS9, do you see RA and DEC
displayed in the "alpha" and "delta" boxes above the image? If so,
that means I am missing something in the header. If you do see RA
and DEC in DS9 (or don't have access to DS9), I would like to get
a copy of this image for testing if possible.
By the way, what is your end goal after alignment? Do you
intend to build an RGB color image from 3 different images?
Karen
On 2/4/2013 4:52 PM, rkohrs [via AstroImageJ] wrote:
"karenacollins [via AstroImageJ]" <[hidden email]>
writes:
>Hi Russ,
> Thanks for the nice comments. The short answer to your
question is
>unfortunately no at this time. However, I do plan to offer
this feature
>in the near term. Do you need a solution right away or do we
have some
>time? We currently only support TAN and SIN WCS projections
(with or
>without SIP distortion corrections), although we will
eventually add
>support for all projections defined in the FITS WCS spec.
Different
>projections are relatively easy to add as long as I have
some sample
>images with the appropriate WCS headers for testing. Could
you work with
>a limited number of projections initially? If so, which
projections would
>be required to get started and could you provide a sample
image with each
>projection? We could do the file exchange outside this forum
if desired.
Hi Karen,
Thanks for the answer. In response, I'd have to say that I'm not
entirely
sure about the projections you are referring to. I"m relatively
new to
WCS. I had hoped to do this with students prior to the end of the
school
year, but we can certainly just do some optical image manipulation
in
place of doing any multi-wavelength overlays.
Actually, here is the link to the radio data collected for M42 by
the 20m.
http://www.gb.nrao.edu/20m/peak/M42/Skynet_56260_M42_4880_3D.htm
You'll see two links for FITS data, FITS L and FITS R, which
correspond to
left and right polarization. This is an example of the radio data
that
I'm working with. If you click on "Log", there are also links for
Orion-A
or M42 that would be really interesting candidates for overlays.
Perhaps
you can see what you need in the header information?
Here is an example of the header information from on image of M42
on the
optical side:
Header listing for HDU #1:
SIMPLE = T
BITPIX = 16 /8 unsigned int, 16 & 32 int,
-32 & -64 real
NAXIS = 2 /number of axes
NAXIS1 = 1024 /fastest changing axis
NAXIS2 = 1024 /next to fastest changing axis
BSCALE = 1.0000000000000000 /physical = BZERO +
BSCALE*array_value
BZERO = 32768.000000000000 /physical = BZERO +
BSCALE*array_value
OBJECT = ' '
TELESCOP= ' ' / telescope used to acquire this
image
INSTRUME= 'Apogee Alta'
OBSERVER= 'greenbank' / Skynet user who submitted
observation
NOTES = ' '
DATE-OBS= '2013-01-04T03:19:30' /YYYY-MM-DDThh:mm:ss observation
start, UT
EXPTIME = 20.000000000000000 /Exposure time in seconds
EXPOSURE= 20.000000000000000 /Exposure time in seconds
SET-TEMP= -20.000000000000000 /CCD temperature setpoint in C
CCD-TEMP= -20.163948750000003 /CCD temperature at start of
exposure in C
XPIXSZ = 13.000000000000002 /Pixel Width in microns (after
binning)
YPIXSZ = 13.000000000000002 /Pixel Height in microns (after
binning)
XBINNING= 1 /Binning factor in width
YBINNING= 1 /Binning factor in height
XORGSUBF= 0 /Subframe X position in binned
pixels
YORGSUBF= 0 /Subframe Y position in binned
pixels
FILTER = 'Red ' / Filter used when taking image
IMAGETYP= 'Light Frame' / Type of image
FOCALLEN= 4565.0000000000000 /Focal length of telescope in mm
APTDIA = 0.00000000000000000 /Aperture diameter of telescope in
mm
APTAREA = 0.00000000000000000 /Aperture area of telescope in mm^2
SWCREATE= 'MaxIm DL Version 4.60' /Name of software that created
the image
SBSTDVER= 'SBFITSEXT Version 1.0' /Version of SBFITSEXT standard
in effect
FLIPSTAT= 'Mirror '
SWOWNER = 'Jack Harvey' / Licensed owner of software
LATITUDE= -0.526523656536 / Latitude in radians; negative =
south
LONGITUD= -1.235786194639 / Longitude in radians; negative =
west
RA = '05:35:17.3' / Target Right Ascension, J2000
DEC = '-05:23:27.202' / Declination of target, J2000
TELRA = '05:35:17.3' / Right Ascension reported by
telescope,
J2000
TELDEC = '-05:23:27.202' / Declination reported by
telescope, J2000
OBJRA = '05:35:17.3' / Right Ascension of object, J2000
OBJDEC = '-05:23:27.202' / Declination of object
EPOCH = 2000. / Epoch of coordinates
JD = 2456296.63851207 / Julian day at start of exposure
SWVER = 'Terminator - 2011.12.12' / Software used for telescope
control
LST = '05:31:50.3' / Local sidereal time at start of
exposure
HA = -0.0575049437091006 / Hour angle at exp start; neg =
east of
meridian
SITEELEV= 7000. / Site elevation, meters
SECPIX = 0.59 / Image scale, arcsec per pixel
OBSERVAT= 'Prompt3 ' / Name of observatory or telescope
ZA = 24.7900257064464 / Zenith angle at start of
exposure, degrees
AIRMASS = 1.10128809772641 / Airmass at start of exposure
AZIMUTH = '+02:25:37.804' / Azimuth in degrees; 0 = North, 90
= east
ELEVATIO= '+65:11:49.151' / Target elevation in degrees; 0 =
horizon,
90 =
DATE = '2013-01-04' / Date at start of exposure, UT
TIME-OBS= '03:19:27.443' / Time at start of observation, UT
FOCUSPOS= 1601 / Position of focus motor
SUNELEV = -32.9954819008038 / Sun elevation, degrees
OBSID = 696448 / Skynet observation ID
EXPID = 7728814 / Skynet exposure ID
GRBID = -1 / Skynet GRB ID
LATSTR = '-30:10:3.300' / Telescope latitude string;
negative =
south
LONGSTR = '-70:48:19.200' / Telescope longitude string;
negative =
west
END
These data are publicly available, so I don't mind discussing them
here
for now.
Dum spiro spero,
Russ Kohrs
A Husband and Father
Who teaches Geology and Astronomy...
Who insists that every rock can tell a story...
Who is transfixed by seemingly esoteric astrophysical concepts...
Who thinks of white-washed buildings and gold mosaics when he eats
any
olive...
Who loves chili, particularly with pasta, hot sauce, onions, and
copious
amounts of cheese...
And who would be happy to play bagpipes for your event!
http://www.wix.com/rkohrs/shenandoahpiper
You will certainly not doubt the necessity of studying astronomy
and
physics, if you are desirous of comprehending the relation between
the
world and Providence as it is in reality, and not according to
imagination.
-- Maimonides