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Coordinate entries

The format for a coordinate line is

<id> <RA> <Dec> [Wt] [SL] [Offset] [X] [Y]

<id> Identification number of object.

<RA> Right Ascension of object. RA is in hours of time, and should be a sexagesimal string, that is standard hours minutes seconds (HH MM SS.SSS) format, although formats such as HH MM.MMMMM, or even HH.HHHH are also accepted.

<Dec> Declination of object. This is in degrees and should also be in sexagesimal format (+--DD MM SS.SS), although formats such as +--DD MM.MMMMM, or +--DD.DDDDDD are also acceptable. The sign of the declination (+--) is optional for northern objects but mandatory for southern objects.

[Wt] Weight for growing slits. Larger weights mean slits grow faster. Wt = 0.0 is reserved for fiducial stars used for aligning the mask. A centred hole is placed at the mask position of such objects, while slits are used for other (WT > 0) objects. Negative weights should not be used, except for WT = MISVAL = -32767, which marks a deleted object.

[Sl] The slit length (or fiducial hole diameter). The default units are arcsecs, although this can be changed with the MMUNit keyword.

[Offset] The Y coordinate difference between the slit centre and object position: Offset = Ycen - Yobj. The slits are drawn parallel to the Y axis, and therefore they have the same X coordinate as the object. The default units are arcsecs, although this can be changed with the MMUNit keyword.

[X] The X coordinate of the object on the mask in mm.

[Y] The Y coordinate of the object on the mask in mm.

The fields in angle brackets (<>) are required, while those in square brackets ([]) are optional. Fields are separated by one or more spaces. Defaults are assumed for blank fields, and were denoted by a word starting with ``*". X and Y are written with a WRITE/CAT but are ignored by READ/CAT which recalculates them from the positions and field centre parameters.