To use this Skyculture, copy all of the files into ~/.stellarium/skycultures/western_SnT
(for Linux and Mac) or %AppData%\Stellarium\skycultures\western_SnT (for Windows).
If you're so inclined, you can even just clone this repository directly into your
skycultures directory:
$ cd ~/.stellarium/
$ mkdir -p skycultures
$ cd skycultures
$ git clone https://github.com/skaven81/western_SnT
This will create a western_SnT directory under skycultures and you're ready to go.
To "upgrade" to the latest version, just cd to the clone and run git pull.
The constellation shapes (constellationship.fab) are generated using
the generate_constellationship.py script. This script accepts
Sky & Telescope's constellation data (SnT_constellations.txt) on STDIN,
and returns Stellarium's constellation shape syntax to STDOUT. Diagnostic
and progress data are printed to STDERR.
To generate a new constellationship.fab file:
# Create a Python virtualenv to work in
$ virtualenv -p /usr/bin/python3 python_virtualenv
$ . python_virtualenv/bin/activate
$ pip install astroquery percache
# Generate the constellationship.fab file
$ ./generate_constellationship.py < SnT_constellations.txt > constellationship.fab
# (optional) force doing new VizieR queries
$ rm .hip_cache
The script queries the VizieR service (http://vizier.u-strasbg.fr/viz-bin/VizieR)
to translate the RA/Dec line endpoints in the S&T data, to Hipparcos
catalog IDs used by Stellarium. Since querying VizieR can take a while
(a few seconds for each star), a cache is implemented so that previous
results are cached in the .hip_cache file for use by subsequent
runs of the script. If you make changes to the get_hip() function,
you should delete the .hip_cache file to ensure that you don't return
cached values.
Sky & Telescope draws constellation lines with various line weights. For example, the "teaspoon" asterism to the east of the "teapot" of Sagittarius is drawn using lighter lines than the primary constellation.
Stellarium does not have any way to draw different weights of constellation
lines, so generate_constellationship.py simply draws all of them. It
would be relatively easy to build in a filter so that it only includes
the heaviest weighted lines, but for the purposes of trying to make
Stellarium's lines look the most like what you see in a Sky & Telescope
atlas, having all of the lines is preferable.
Sky & Telescope uses a convention of terminating constellation lines that end at a star outside the constellation (for example, Alpheratz in Pegasus) a half-degree short of the target star. Stellarium's constellation line drawing feature requires that all lines terminate at stars.
Sky & Telescope does not provide constellation lines for Microscopium
and Mensa. Thus the computed constellationship.fab file contains
only 86 of the 88 constellations.
Sky & Telescope provided a Word document (SnT_star_names.docx) that contain
the names of the stars used in Sky & Telescope publications. A script is
provided (generate_star_names.py) that is able to extract the star names
from this file, look up each star in the Hipparcos catalog (using VizieR),
and return a star_names.fab formatted output.
To generate a new star_names.fab file:
# Create a Python virtualenv to work in
$ virtualenv -p /usr/bin/python3 python_virtualenv
$ . python_virtualenv/bin/activate
$ pip install astroquery percache python-docx
# Generate the star_names.fab file
$ ./generate_star_names.py SnT_star_names.docx > star_names.fab
# (optional) force doing new VizieR queries
$ rm .hip_cache_stars