StarGazer v1.3 Documentation

Introduction

StarGazer is a web based system for star map drawing. Currently it works with GSC-ACT, SAO, YBS, a subset of USNO-A2 (all stars up to 16.3m), Tycho-I and some other catalogs. At present StarGazer is able to:
  • Search objects by name.
  • Draw a map with specified Stellar catalog, center of the field, field of view and maximal magnitude using Gnomonic projection.
  • Draw deepsky objects on the map.
  • Label objects on the map with their catalog IDs or their magnitude.
  • Label objects brighter than specified magnitude or leave them unlabeled.
  • Generate maps for printing on different paper formats (A3, A4, Letter etc.).
  • Generate output in Adobe PostScript and PDF format. The PDF support is not very good and some problems may occur with the PDF output. I'm planning better support for it in the future.
StarGazer is written in Perl and uses PostgreSQL as a search engine. GSC-ACT catalog is the main one because of its over 19,000,000 entries up to magnitude 16m and via the Tycho-I catalog it has cross-references with some other catalogs.
NOTE! The native output of StarGazer is PostScript. PDFs are generated from StarGazer's output by GhostScript. That is why some problems may occur with the PDF output.

How to use it?

If you know the coordinates of the object, go to the StarGazer, or if you do not know them go to the Search menu. Fill the necessary fields and enjoy StarGazer.

Searching
  • Enter the name of the object you are looking for in the search form.
  • Choose the method of search. If you know the exact name of the object choose "Exact Match" otherways choose some other search method or use the default one.
  • Select the maximum number of objects returned by the search. The default should be enough.
  • Click on "GetMap" for the corresponding object to get the map.
NOTE! Do not rely on the values of "Label limit" and "Field of view" filled by the search. The object will appear but the map could be quite unusable. Modify this fields according to your needs!

A brief description of StarGazer's fields
  • Map Title - Title of the map (optional).
  • Center RA - Right Ascension of the map center in hours.
  • Center DE - Declination of the map center in degrees.
  • Coordinates equinox - Equinox of the "Center RA" and "Center DE" in years - usually 2000 or 1950. If not specified, the equinox of the catalog coordinates is used.
  • Map equinox - Equinox in which the map will be drawn. If not specified, the equinox of the catalog coordinates is used.
  • Field of view - Field of view of the map in degrees.
  • Catalog - Catalog used for the map drawing.
  • Magnitude limit - Magnitude of the faintest star on the map (optional default is 10).
  • Label limit - Magnitude of the faintest labeled star(optional).
  • Deepsky objects catalog - Catalog used for deepsky objects drawing.
  • Deepsky objects magnitude limit - Magnitude of the faintest deepsky object on the map (optional default is 12).
  • Label type - Type of the labels used for the stars.
  • Media type - Paper type on which the map will be printed.
  • Grid density - Maximum grid lines (if any) in each dimension. The real number of grid lines is usually smaller than the given, because StarGazer is trying to find "nice" grid steps for RA and DE .
  • Gridline style - What kind of line should be used for drawing the Gridline. This option does nothing if "Grid density" is set to "No grid".
  • Put center mark - Self explanatory ;-).
  • Output file format - Choose the file format of the map. PostScript and PDF format can be generated by Stargazer. PostScript is preferable because it is generated directly from StarGazer while PDF is converted from PostScript to PDF by GhostScript.
When ready click on the button "Generate the map" and wait while the map is downloading. You will need GhostScript to be able to see the PostScript map or you can send the file directly to the printer if you have a PostScript compatible one.

Frequently Asked Questions

The FAQ is available here.

The Author

My name is Rumen Bogdanovski. More information about me you can find on my web page. If you have any questions, proposals or critical notes, do not hesitate to send me an e-mail at rumen_at_skyarchive.org
I would like to thank my friend Ivailo Kassamakov who helped me in exploring the PostScript language.



Rumen G.Bogdanovski
© 2001-2012