The purpose of fchart is to create practical, well readable, detailed finder charts for deepsky observing. It has no graphical user interface, just a commandline interface. It creates Postscript (EPS) or PDF files that may be printed or viewed on any common platform (Linux, UNIX, Mac, Windows). I chose to use the Tycho-2 catalog for the stars, but the (binary) star database format is so simple that one can convert ANY star catalog to it in a simple way.
The current version has automatic label placement, minimizing the number of labels that are drawn on top of each other.
I only have Linux boxes at my disposal, so I know it works on Linux. It may nevertheless accidentally run on other platforms that support python.
To the right you see an example image of the M 81 / M 82 area. Click the image for a higher resolution map. The original is available here:
All messier objects in EPS format (.tar.gz) (2.1 MB)
All objects in the H800 list in one, 400 page atlas. The deepsky limiting magnitude of the maps is 14.0 and the maps are 3 degrees in diameter. THe maps are combined using LaTeX: h800.pdf (9 MB)
This software comes with ABSOLUTELY NO WARRANTY. It is distributed under the GNU General Public License.
Get the software
fchart is a collection of python scripts. It makes use of the numarray library of the space telescope science institute. It also uses (and distributes) data from the revised NGC/IC project and the Saguaro Astronomy Club. To have stars, you'll need to download the Tycho 2 catalog and process it with the tyc2_to_binary.py script, provided in the distribution. You can also just download the "tyc2.bin" file below and copy it to your "$PREFIX/fchart/catalogs/" directory.
download fchart-0.2.tar.gz (1.1 MB)
download fchart-0.2.zip (1.1 MB)
download tyc2.bin (29 MB)
download fchart-0.1.tar.gz (1.1 MB)
download fchart-0.1.zip (1.1 MB)
Read the README file for installation instructions. After installation, run "python fchart --help". On Linux/UNIX machine, one may omit the "python" command.
Format of star database
(advanced) The format of the star database is very simple. One star per record. One record consists of three 32 bit IEEE floating point numbers in big endian format (most significant byte first). These numbers represent the J2000 right ascension (radians) and declination (radians) and the magnitude of the star.
The following code puts two stars in the database:
from numarray import *
stars = zeros((2,3),type=Float32)
stars[0,:] = [1.0, -0.2, 9.3] # [RA, DEC, MAG]
stars[1,:] = [5.7,+0.142946, 4.3] # [RA, DEC, MAG]
if sys.byteorder == 'little':
out = file('data/tyc2.bin', 'w')