mExamine [-d][-p ra dec radius] image.fits
mExamine returns information about the sky coverage of a FITS
image (assuming WCS keywords in the header) and optionally
pixel statistics for a region in the image.
- -p ra dec radius
Return information about a region (central pixel value, min, max
values and location, etc.) Coordinates and radius are in
degrees unless given a "p" suffix, in which case they are in pixels.
Turn on debugging.
FITS file to examine. If the file has multiple HDUs, you can add
that to the file name, e.g., "m51.fits". If an HDU is
a datacube, you can select a plane ("m51.fits"). Even if
there is a single HDU, you need to specify it if you want to
specify a cube plane ("m51.fits"). Note that this syntax
may require quotes around the file name string to avoid confusing
If successful, returns the following:
proj Image projection
csys Coordinate system
equinox Coordinate system equinox
naxis Number of axes in the file
naxis1 Image width (in pixels)
naxis2 Image height
naxis3 Data cube depth (only if NAXIS > 2)
naxis4 Data cube fourth dimension (only if NAXIS > 3)
crval1 WCS reference coordinate for first axis
crval2 WCS reference coordinate for second axis
crpix1 Pixel value for reference coordinate
cdelt1 Pixel scale (degrees)
crota2 Rotation of image (E of N)
lonc Sky coordinate of image center
ximgsize Image size (degrees)
rotequ Rotation of image in Equatorial (J2000)
rac Equatorial (J2000) coordinates of image center
ra1 Equatorial coordinates of four image corners
radius Radius of pixel region (degrees)
radpix Radius in pixels
npixel Number of pixels in region
nnull Number of null pixels
aveflux Average flux for region
rmsflux RMS of region fluxes
fluxref Flux for reference location
sigmaref RMS of fluxes
xref Pixel coordinates of reference location
raref Equatorial (J2000) coordinated of reference location
fluxmin Same for pixel with minimum flux
fluxmax Same for pixel with maximum flux
If you specify region that is all blank, npixel will be zero, nnull will
be the total number of pixel examined, and the flux related parameters will
all be zero.
- No ra, dec, radius location given or file name missing
- File name missing
- Cannot open FITS file test.fits
- Cannot find WCS keys in FITS file test.fits
- WCS initialization failed.
- Location off the image.
Error reading FITS data.
- mExamine -p 202.5 47.0 0.01 aJ_asky_980527n0240232.fits
[struct stat="OK", proj="SIN", csys="EQUJ", equinox=2000.0, naxis1=512, naxis2=1024, crval1=202.5213942, crval2=47.1131924, crpix1=256.5, crpix2=512.5, cdelt1=0.0002778, cdelt2=0.0002778, crota2=0.0034, lonc=202.5213942, latc=47.1134702, ximgsize=0.142222, yimgsize=0.142222, rotequ=0.0034, rac=202.5213942, decc=47.1131924, ra1=202.6260252, dec1=46.9706487, ra2=202.4171950, dec2=46.9706407, ra3=202.4166112, dec3=47.2553630, ra4=202.6265617, dec4=47.2553710, radius=0.0100000, radpix=36.00, npixel=5476, nnull=0, aveflux=136.807, rmsflux=0.853615, fluxref=137.3, sigmaref=0.578143, xref=309, yref=105, raref=202.5000208, decref=46.9999951, fluxmin=135.042, sigmamin=-2.06764, xmin=328, ymin=77, ramin=202.4922870, decmin=46.9922153, fluxmax=152.299, sigmamax=18.1493, xmax=307, ymax=117, ramax=202.5008338, decmax=47.0033286]
BUGSThe drizzle algorithm has been implemented but has not been tested in this release.
If a header template contains carriage returns (i.e., created/modified on a Windows machine), the cfitsio library will be unable to read it properly, resulting in the error: [struct stat="ERROR", status=207, msg="illegal character in keyword"]
It is best for the background correction algorithms if the area described in the header template completely encloses all of the input images in their entirety. If parts of input images are "chopped off" by the header template, the background correction will be affected. We recommend you use an expanded header for the reprojection and background modeling steps, returning to the originally desired header size for the final coaddition. The default background matching assumes that there are no non-linear background variations in the individual images (and therefore in the overlap differences). If there is any uncertainty in this regard, it is safer to turn on the "level only" background matching (the "-l" flag in mBgModel.
COPYRIGHT2001-2015 California Institute of Technology, Pasadena, California
If your research uses Montage, please include the following acknowledgement: "This research made use of Montage. It is funded by the National Science Foundation under Grant Number ACI-1440620, and was previously funded by the National Aeronautics and Space Administration's Earth Science Technology Office, Computation Technologies Project, under Cooperative Agreement Number NCC5-626 between NASA and the California Institute of Technology."
The Montage distribution includes an adaptation of the MOPEX algorithm developed at the Spitzer Science Center.