Overlooked System Features

You can use the translit task as a stream editor to help in parsing comma-delimited strings. For example, to parse this header card:

cc> imhead lris0106 l+ | match WINDOW
WINDOW = '1,0,0,2048,2048' /


You can use this set of commands in your script:

hselect (image, "window", "yes") | \
translit ("STDIN", ",", " ") | \
scan (winchip, winxstart, winystart, winxlen, winylen)


Starting with V2.11 FITS images are supported directly as an alternative to other IRAF image formats (e.g., .imh, .hhh). This means that you do not have to convert disk files using RFITS, as in the past.

You can generate Postscript or EPS hardcopy files of plots using the psdump or eps device names respectively. Using psdump will create a file in the /tmp directory named irafdmpXXX.ps (where the XXX is a process id) containing the plot Postscript, using eps will create a file sgiXXX.eps in the current directory. For example,


cl> contour dev$pix dev=psdump
cl> implot dev$pix
.... in cursor mode use ":.snap eps"

Help pages for the development IRAF system and all external packages installed at NOAO are available from our web page: http://iraf.noao.edu .

The references task can be used to locate tasks that deal with specific topics. Use
cl> references updquick+

to update a database for faster searches.

The gdevices command will list all configured image display frame buffers.

After resetting the imdir variable you can move all existing .pix files for an image to this new location using IMCOPY or IMRENAME. For example,

cl> reset imdir = HDR$pix/
cl> imcopy *.imh *.imh

The hfix task can be used to edit image headers with any user specified commands. By default the user is put into the editor to modify the editor, but the command can also make use of host programs such as sed or awk to perform more complex and automated editing.

The astutil.astcalc task can be used as a general expression evaluator that understands astronomical concepts such as precession, julian date, airmass, etc.

The astutil.asthedit task can evaluate expressions and edit image headers using image header keywords, tables, CL parameters, internal variables or constants. It differs from hedit in that it includes astronomical functions which can be used in the expressions. For example, to add the HA to an image create a command file that computes the sidereal time and subtracts the RA, e.g.

	ha = real(mst(date,ut,obsdb("cfht", "Longitude"))) - (ra)