ISOCAM Interactive Analysis User's Manual Version 5.0 - ISO - ESA

146 CHAPTER 14. IMAGE ANALYSIS AND DISPLAY
You need to supply the astronomical name of the object which you wish to overlay, or its
position in RA(J2000) and DEC(J2000), and the size of the image in arcminutes. (Be sure
to request an image of size comparable to the CAM image you wish to compare it to.)
Further instructions can be found on the Web page.
Note that the images from the DSS are in a particular FITS format (GSSS astrometry), and
need to be converted to ISO FITS with the CIA routine palomar to iso. The first argument
is the DSS FITS file and the second is the output ISO FITS file.
CIA> palomar_to_iso, ’dss.10.45.22+55.57.35.fits’, ’haro3_iso.fits’
You can now use your FITS file as input to isocont for displaying (see Section 14.6.2) or
xdisp for analysis (see section 14.3.1).
14.6.2 isocont
We include a only brief description of isocont with examples here. For a fuller guide to its use
your attention is drawn to – Claret A., Charmandaris V., Gastaud R., 1997, A Learning Guide
for ISOCONT, v1.0.
isocont accepts two arguments, either one can be a FITS image or a CAM image in a raster
data structure 8 . (Because isocont needs astrometry for both images, the CAM image must be
contained in a raster data structure and the entire structure must be passed as an argument.)
Whichever image is the first argument, its astrometry is used as a reference, and the image of the
second argument is rotated or aligned so positions and orientation of both images match. The
first argument is plotted in grey-scale or colour, and the second as contour levels. Figure 14.16
shows an optical image in grey-scale overlayed with contours from a CAM image.
Examples of isocont usage are:
• Following the examples of Section 12.2 and Section 13.2, our first example here displays an
optical image of Haro 3, overlayed with a CAM raster image. The keyword mag magnifies
the image for readability.
CIA> isocont, ’haro3.fits’, lw6_raster, mag=4
This command produced the image in Figure 14.16.
• Following from the example in Section 14.3.1.2 we can overlay the xdisp generated FITS
file, which contains a ‘zoom’ of the LW6 CAM raster image of Haro 3, with contours from
the optical image of Haro 3. The keyword putinfo adds information to the window: the
intensity scale, contour level values etc.
CIA> isocont, ’ima33x33.fits’, ’haro3.fits’, /putinfo
• This example is similar to the previous one, except the keywords radec and scan are
set. Respectively, these display the image oriented in standard astronomical fashion (i.e.
orienting the +DEC axis upwards and labelling it in degs min secs and orienting the +RA
axis leftwards and labelling it hrsminssecs) and indicate the individual positions of each
CAM state in the raster.
8 The CAM raster data structure must be present in the memory of the CIA session and the FITS image must
be accessible on disk.