Catalogue format

A catalogue for the telescope computer is a set of user interface commands and as such can be in free format. For legibility and neatness, however, it is worth adhering to a more rigid tabular format with one object per line of the file. The guidelines for generating catalogues may be divided into essential rules (disregard of which will cause the interface to be unable to read in the file) and conventions (which are guidelines for producing catalogues which may be read in as quickly as possible and are easy to maintain).

Essential rules

The following rules MUST be followed.

1. The file should consist of 80-byte records. Consequently, no more than 80 characters per line are allowed.
2. There should be no non-alphanumeric characters (carriage returns, line feeds, etc.) anywhere in the file.
3. The filename must consist of 8 alphanumeric characters or less, starting with a letter, and must have the extension `.CAT'.
4. There should be no more than 500 objects in the file, as this is the maximum number that can be held in memory at once.

Conventions

1. Every standard catalogue should start with a comment line giving its contents and giving the name of the originator.
2. If all of the objects in the catalogue have the same equinox, and coordinate type (ie J B or A(pparent)) then this should be given at the beginning of the file, not repeated for every object.
3. The format should be as given in the examples below, i.e.:

   SO OBJECT R hh mm ss.ss D +dd mm ss.s P/R +s.ssss P/D +s.sss EQ Jyyyy.y

   with the equinox omitted if it does not change from line to line.

4. It is expected that each catalogue file will have an associated documentation file with the same name but with the extension `.DOC'.
5. Catalogues should be split by Right Ascension in order to minimise the number of records to be read in - there is no point storing objects if they are unobservable..

Coordinate Systems

The restrictions on coordinate types are as follows:

1. Coordinates may be either mean or geocentric apparent. B1950 (FK4) and J2000 coordinates are supported at present.
2. Geocentric Apparent coordinates refer to the current date and time.
3. The epoch for the proper motions must be equal to the equinox for mean coordinates. (Conversions can be made using the COCO program on the VAX 8300, if necessary.)