Memo for WCSTools

Recently I have been more dissatisfied with astrometry.net, because no matter how I tweak the parameters, some portions in an image can never have catalogue stars’ positions overlaid with the corresponding actual stars. I also have learnt that astrometry.net only provides crude solutions to plate constants of images, and therefore, if one needs high-quality astrometry, WCS by astrometry.net is not accurate enough yet, and other better astrometric software should be used. This is the reason why I need to use WCSTools.

The following is simply a memo to record my steps to install the software. My reference is basically from this webpage.

(1) Download the latest version of WCSTools (3.9.4).

(2) Go to the directory where the file is downloaded, and type in the following commands to install it:

$ tar xvfz wcstools-3.9.4.tar.gz
$ cd wcstools-3.9.4
$ make all

(3) Now the environment needs to be set:

$ sudo cp wcstools /usr/local/bin/
$ sudo cp ./bin/* /usr/local/bin/
$ sudo cp libwcs/*.h /usr/local/include/
$ sudo cp libwcs/libwcs.a /usr/local/lib/

(4) Test the installation:

$ wcstools

(5) You should see a very lengthy message including the version of the software, as well as a number of programme names. The following is what I can get (truncated):

WCSTools 3.9.4 Programs
http://tdc-www.harvard.edu/software/wcstools/

addpix:    Add a constant value(s) to specified pixel(s)
bincat:    Bin a catalog into a FITS image in flux or number
char2sp:   Replace this character with spaces in output (default=_)
conpix:    Operate on all of the pixels of an image
cphead:    Copy keyword values between FITS or IRAF images
crlf:      Change CR's to newlines in text file (for imwcs, imstar logs)
delhead:   Delete specified keywords from FITS or IRAF image file headers
...

Since I am using an online servers to visit star catalogues, the environment variables such as the following ones have been set:

setenv UB1_PATH http://tdc-www.harvard.edu/cgi-bin/scat
setenv SAO_PATH http://tdc-www.harvard.edu/cgi-bin/scat
setenv UCAC3_PATH http://tdc-www.harvard.edu/cgi-bin/scat

Note that I haven’t yet figured out how to connect to catalogue UCAC4. Apparently WCSTools cannot cope with the newly released Gaia either.

As still being in a process of learning the software, I may update this post infrequently in the future.

Memo for WCSTools