Genmap is a script written in Ruby to generate simple star maps in scalable vector graphics (SVG) format. My original intent was to generate diagrams showing the location of the Herschel 400 objects on the Sky Atlas 2000 maps, something like the following:
After discovering Diego Hernangomez's excellent repository of celestial data in geojson format, I expanded the tool to add more and more information layers. The end result looks like this:
After you download the source files for star-maps, you should be able to run genmaps from the top-level directory, assuming you have Ruby installed. Genmaps assumes Ruby is located in /usr/bin. If not, you may need to edit the top line of genmaps to point to your Ruby installation.
Usage: genmap [options]
-w, --width INCHES Width of image in inches
-d, --dpi PX_PER_IN Image fineness scale
-m, --map NUM Sky Atlas 2000 map number
-u, --ul DDDD.D+DDDD Upper-left map coordinate
-l, --lr DDDD.D+DDDD Lower-right map coordinate
-S, --stars MAG Plot stars
-G, --grid Plot grid
-H, --herschel Plot Herschel 400 objects
-I, --herschel2 Plot Herschel II objects
-p, --plus Print dsos as plus signs
-M, --messier Plot Messier objects
-D, --dso MAG Plot deep sky objects
-C, --const Plot constellation lines
-B, --border Plot constellation borders
-W, --milkyway Plot milky way contours
Note, the map extent is either specified via the Sky Atlas 2000 map number or by the upper-left and lower-right coordinates.
Genmap downloads and caches data files in the data directory. The
output of genmap is an SVG file written to stdout. You should
redirect this to a file. The easiest way to view a map is to point a
web browser to it using a local file URL, e.g.,
file:///c:/<path>. The SVG content can be included in a web page
using the <IMG> tag or it can be viewed in an SVG editor, such as
Inkscape. Inkscape can also be used to convert the SVG content to PDF
or various image formats.
Two PDF maps at the outer level cover the Herschel 400 objects and the Hershel II objects.