Guide Star Catalogue

C2A is able to read the original Guide Star catalogue (version 1.1) both in its original format and in a compiled format for C2A. It can also read the 1.2 and ACT versions of the GSC catalogue in their native formats. The catalogue includes 18,839,509 stellar and non-stellar objects. You select this as the current catalogue through the Stars tab of the Options dialogue box, or by SHIFT-right-clicking on the map.

The information associated with objects in the compiled version of the Guide Star 1.1 catalogue is as follows:

  • magnitude,
  • object type (star or non-stellar object),
  • the right ascension for the epoch 2000,
  • the declination for the epoch 2000.

Some information present in the original Guide Star catalogue are not provided in the compiled version but are available in the original 1.1 version as well as in the 1.2 and ACT versions of the GSC. These are namely:

  • the objectís reference (in the form GSC <n1> / <n2> where <n1> is the number of the Small Region et <n2> is the index in the region),
  • the position error in arc seconds,
  • the magnitude error,
  • the reference to the Schmidt plate that was used to identify the star.

You can find the compiled version for C2A of the Guide Star 1.1 catalogue in the Download page on the C2A Website. C2A can also read the format of the original catalogue, but the compiled catalogue speeds up the display of objects.

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