GDL setup Astronomy library

January 21, 2026

To setup the IDL / GDL Astronomy library on Linux with GDL, install GDL. Download IDL Astronomy Library:

git clone https://github.com/wlandsman/IDLAstro.git

export GDL_PATH=$(realpath ./IDLAstro):$GDL_PATH
# add this line to /.bashrc or ~/.zshrc

Check: reopen Terminal and type

gdl -e "print, !PATH"

and IDLAstro directory should be included in the printout.

Examples

hor2eq, ten(37,54,41), ten(264,55,06), 2466879.7083333d, ra, dec,  /verb, obs='kpno', pres=781.0, temp=273.0

reading .fits:

Download NASA example FITS file and extract

tar xf w0bs0102t_c0h.fit.gz

From gdl show an image from Hubble Space Telescope.

FITS_READ, 'w0bs0102t_c0h.fit', data, header

TVSCL,data

Show FITS headers

PRINT,header