zero [ra=hh:mm:ss.s] [dec=dd:mm:ss] zero [last] zero [cra=%f] [cdec=%f]When zero is used as in the first line, this tells the telescope control programthe value given on the command line should be used as the zero point. The program will then adjust the additive constants to the pointing programs so that future point commands (see section 5.1.13) will refer to this origin.
The last keyword can be used in place of specifying the coordinates.
The additive constants (cra= and cdec=) can be set manually by specifying them on the command line. The values revert to 0.0 when the program is restarted.