Gaialaxy is a modern fortran code designed to produce an all sky color image encoding the mean integrated flux coming from all light sources measured by the fantastic Gaia satellite (ESA), i.e., from more than a billion stars from our Galaxy and its nearby satellites.
By default, the fluxes are calibrated in W/m^2/nm/sr and the output colors are in the linear sRGB color space. Other units and color transformation matrices can be trivially set in the main program file (gaialaxy.f03). Check out the python code spectroll to compute color matrices from scratch.
Please ensure that you have a working installation of the gfortran and gcc compilers (or alternatives), the cfitsio and wcslib libraries. Editing the provided Makefile is certainly needed to specify the install location of these libraries.
The (empty) directory "data/" should be filled with Gaia data under the form of votable files (in the fits format) and named as "gaiadata_01.fits", gaiadata_02.fits" etc...
The tables are expected to be of 6 columns (tfields) containing an identificator of the source source_id, its galactic coordinates l and b, the flux in the G band, the flux in the RP band and, finally, the flux in the BP band. These data can be obtained from the ESA/Gaia/DPAC data archives.
An example ADQL language query, which retrieves 100 sources in some sky patch, reads:
curl -k -b cookies.txt -X POST --form PHASE=run
--form LANG=ADQL --form REQUEST=doQuery --form FORMAT=fits \
--form QUERY="SELECT TOP 100 \
source_id,l,b,phot_g_mean_flux,phot_rp_mean_flux,phot_bp_mean_flux \
FROM gaiaedr3.gaia_source \
WHERE phot_g_mean_mag >=10 AND phot_rp_mean_mag >=10 AND phot_bp_mean_mag >=10 \
AND l<180.0 and b >=0" "https://gea.esac.esa.int/tap-server/tap/async"
A 2048x1024 pixels image of our galaxy:
But nothing prevents you to go large, very large, very very large: Gaialaxy.png
Have fun!
This code uses data which are in the public domain and are provided by the European Space Agency (ESA) mission Gaia, processed by the Gaia Data Processing and Analysis Consortium DPAC. Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.