1. MSOTCS: a new x86/QNX-based control system for the RSAA 2.3m telescope The current control system for the RSAA 2.3 metre telescope is a Digital Equipment  VAX 3200 computer running the VMS operating system. The new TCS takes the form of an embedded system using an industrial x86 computer and the QNX6 RTOS. If you are an observer with experience of the existing VAX/VMS system, the following presentation may assist in accommodating to the new MSOTCS system.

2. Differences between MSOTCS and VAX/VMS Systems Embedded system: the observer does not log in to MSOTCS nor do they have access to the QNX shell; no functionality beyond that provided by MSOTCS commands. No longer uses "startup" files, but configuration files cfiles may be used to configure (customise) the telescope system. New command syntax: [ ] [ ] [...] For example track orbit McNaught2008J3 wait Many verbs, objects and arguments are retained from VAX/VMS… but Qualifiers are now simply additional fields (not /QUALIFIER ); PARAMETER=VALUE syntax not used.

3. Differences between MSOTCS and VAX/VMS Systems Track using coordinate, ephemeris or orbit files; change of format for the fields object_name and epoch ; existing coordinate files should work without modification. MSOTCS now supports beam switching. A beam consists of a preset position on the sky and an associated guide object. Aperture positions are now defined in cartesian (instead of polar) coordinates in the instrument focal plane.

4. Differences between MSOTCS and VAX/VMS Systems User files - cfiles, coordinate, ephemeris and orbit files can be downloaded to the TCS via the LAN from any URL.

5. Command Syntax The syntax takes the general form: [ ] [ ] [ …] Commands, standard parameter values and qualifiers must be in lower-case to be accepted. File names, object names etc incur the usual case sensitivity of a UNIX shell. Abbreviation by any unique string of two or more initial characters, eg ro or rot for rotator command. Any unique contiguous string for subsystem names, eg cov or cover for primary_mirror_cover. Abbreviated forms should never be used in scripts or in documentation.

6. CFILES As for VAX/VMS, the configuration file is the standard means of customizing the telescope system. The new cfile format involves: Configuration variables which are grouped into sections: GENERAL, NASMYTH_A, NASMYTH_B and CASSEGRAIN The assignment symbol is a simple = rather than := Both the characters ! and # are permitted as comment identifiers. Variable names are lower-case; enumerated type values upper-case eg focal_station = NASMYTH_A Simplified specification of compound-valued variables such as apertures, pushbuttons, beams and iaa_source. Cfiles nolonger contain telescope pointing coefficients.

7. Equatorial Coordinate Format Two fields in the coordinate specification have changed: The object-name field may be placed anywhere in the input line but must now be delimited by equals signs: =SN1987A= instead of double-quotes "SN1987A". The epoch parameter which was previously appended to the equinox equinox(epoch) must now be separated by a forward slash: equinox/epoch. UNIX or QNX shell interprets the quoted string and parentheses. Legacy coordinate files will be continue to be read correctly but the changed formats should be employed in all new files and when entering the commands manually.

8. Aperture (Pointing Origin) Definition Apertures may be defined numerically in a cfile, entered at the command line or calibrated by a simple interactive procedure. They are specified in arcseconds in cartesian instead of polar coordinates. When defined in a cfile, separate aperture definitions apply for each of the focal stations Nasmyth_A, Nasmyth_B and Cassegrain.

9. Observing with MSOTCS startup (switches on console & telescope hardware, installs default configuration and pointing corrections). load cfile to customize telescope configuration. open building shutter & mirror cover, set vent fans on. Check the status of telescope subsystems on status screen. rotator (set rotator mode and angle, instr alignment angle) Select an aperture track an object by manually entering coordinates or from a coordinate, orbit or ephemeris file shutdown all (parks telescope, closes shutter & cover and shuts down TCS software).