Rtshell Script Writers Bible

Warning - Script writing and script use should be considered an exercise left to experienced users, those who are familiar with the normal operations of the telescopes and instruments. Please feel free to ask Ted about the workability of specific scripts. Also note comment below about difficulty in terminating scripts.

Rtshell was created by Ted Groner to address several limitations of the long-gone cominterp program. One major limitation was the lack of scripting. Rtshell implements scripting.

Scripts allow files to be sourced to control the following classes of functions:

• 1) Instrument Control
• 2) Telescope Movements
• 3) Unix Commands

How to run scripts

The correct way to run a script, for example a script named my.script, is "source my.script" Adding arguments to invocation will be discussed below.

Writing Scripts

Script Commands

All instrument control and telescope movement commands are built into the rtshell. Some other commands were already built into tcsh, like "pwd". This document will only attempt to cover the commands that were added as built ins to the tcsh shell. Please consult man pages for tcsh(1) and csh(1) for more information about built in commands. Tcsh is a superset of csh, rtshell is a superset of tcsh. All other "system" commands are beyond the scope of this document as well.

Instrument Control Commands

Of special interest to this discussion are the commands "total, go, bias, flat, dark, and comp". These commands all instruct the instrument to expose for a period of time. They were designed to work from the rtshell window, and to return control of the window back to the observer after starting the exposure. This is NOT what is needed in a script. For this reason a special instrument command was created only for use in script files. This command is "gowait"

The gowait command is fully implemented for onlt the fast and ccd programs. It should soon be in use for echelle and sonic. I will use the ccd as an example.

The gowait command for the ccd (and fast) takes the form of:

• ccd gowait [exptime|repcount] [file type[suffix]] where
• exptime stands for length of exposure
• repcount stands for number of exposures (only for BIAS)
• file type stands for the type of exposure(BIAS, FLAT, DARK, COMP)
• suffix stands for a one letter suffix on file name(only FLAT)

The complete list of possible commands becomes

• ccd gowait 30 -- simply expose for 30 seconds, no file type
• ccd gowait 20 FLAT -- take a 20 second flat , named seqnum.FLAT
• ccd gowait 20 FLATV -- take a 20 second flat , named seqnum.FLATV
• ccd gowait BIAS -- take a 0 second bias , named seqnum.BIAS
• ccd gowait 10 COMP -- take a 10 second comp , named seqnum.COMP (FAST)
• ccd gowait 10 DARK -- take a 10 second dark , named seqnum.DARK (not yet)

BEWARE OF "ccd gowait" with NO arguments! This starts an infinite exposure, which never returns!

Telescope Control Commands

The telescope control commands all have the common prefix "tele". Not all commands work on all telescopes, as the hardware differs. First we'll list commands good on both the 60" and 48".

Common Commands

tele coords -- valid commands are:

• "tele coords newcat rudy" - load catalog /Realtime/lib/catalogs/rudy.mct
• "tele coords {1 - load object coords of first line in loaded cat
• "tele coords }TWQSO - load object TWQSO coords from loaded cat

tele enable

This command takes no arguments, and will cause the telescope to slew to the next loaded coordinates. If you don't use this one, telescope WILL NOT MOVE.

48" ONLY Commands

• tele offset 120 -30
  (offset telescope in arc seconds; no "tele enable" command is needed following tele offset commands)

  tele filter 3

  (move to third loaded filter)

  tele focus -100

  (move secondary focus)

  tele gfoc -100

  (move guider focus relative to current)

60" ONLY Commands

• tele comp [IN|OUT] - Move FAST comparison mirror IN/OUT
• tele lamp [HEAR|NEON|INCAND] [on|off] -- toggle FAST lamps
• tele ffoc value - Move FAST spectrograph focus

OTHER COMMANDS

• setcom inst keyword val - Set keyword to val for named instrument

Putting it all Together

Most people learn best from example, so here are several!

48" Focus Script

48" Standard Star Script

48" Dome Flat Script

KILLING A SCRIPT