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Remember the on-line help facility; in most cases it will solve your problem more quickly than searching in the manual.

* (text)

In a line of input to the user interface, all characters following an asterisk are ignored by the command processor. In prepared or SAVEd files it is often useful to indicate the purpose or significance of the commands that follow, to flag and date amendments or to indicate the source of the data values appearing as arguments of commands. Comments may be in blocks of lines, each with an asterisk in column 1, or as in-line comments following a command and its argument.

At the console the text is ignored and the user is prompted for further input; in a file the command processor ignores the text and moves on to interpret the next line.

There are no qualifiers.


is now obsolete and has been replaced by SO(URCE).


defines the autoguider acquisition mode and is used to tell the system whether to move the guide-probes or the telescope when acquiring a guide star.

AC(QUIRE)/PR(OBE) moves the guide probes until the guide-star is centred while the telescope remains fixed (tracking). It is used when the object of interest is already positioned in the TV or on the CCD chip and should stay where it has been put. The position of the guide star will probably not be known very accurately and moving the telescope rather than the probe would cause the target to move.

AC(QUIRE)/TE(LESCOPE) moves the telescope to acquire the star while the guide-probe remains fixed in the focal plane of the telescope. It is used when the guide star position is known a priori ; either because it has been observed before and the probe position is known or because the offset between it and the target has been measured in advance. It is the usual mode for the WFC.

TRAP FOR OLD PLAYERS. These two definitions were previously reversed.


gives details of a source, telescope or UI parameters, or lists the source-names in the resident catalogue.

AD(VISE)/S(OURCE) source-name

gives details of source-name and times to rise and set from a given time. This time is input using SET/LST or SET/UT. If no time has been set, the current time is used.


gives details of the edit source and times to rise and set from a given time. This time is input using SET/LST or SET/UT. If no time has been set, the current time is used.


gives details of the next source and times to rise and set from a given time. This time is input using SET/LST or SET/UT. If no time has been set, the current time is used.


gives details of the current source and times to rise and set from a given time. This time is input using SET/LST or SET/UT. If no time has been set, the current time is used.


gives all telescope parameters such as SET/GUIDE/INCREMENT rates, offsets, focus position and the like.


gives a list of the source-names and sequence-numbers in the resident catalogue.


gives co-ordinates of the edit, current and next sources, acquisition and telescope modes and the time set by SET.

AP(ERTURE)/A x y (arcsecs) sets aperture A AP(ERTURE)/B x y (arcsecs) sets aperture B

sets up aperture offsets defined in an X-Y coordinate system fixed in the instrument rotator. These can be used, for example, to locate an object within a particular aperture or detector pixel. An aperture offset is executed by pushing one of the beamswitch buttons on the control desk.

If it is required to beam-switch (for example on a two channel photometer), then the apertures can be set up using the qualifiers /A and /B with X-Y offsets in arcsecs as input parameters. The control panel BEAMSWITCH buttons are then used to select between either aperture or the nominal position. If the required aperture offsets are not known a priori then the /A and /B qualifiers for SNAFU (q.v.) may be used to set them up interactively.

APERTURE is applied as a pointing correction, so it is not reflected in the displayed telescope position: conceptually, applying an aperture offset causes the SAME object to be observed using a DIFFERENT area of the instrument whereas an RA/Dec offset causes a DIFFERENT object to be observed on the SAME part of the detector and therefore causes the displayed position to change. The RA & DEC displacements corresponding to a particular aperture offset will vary with the turntable rotator position angle (unlike that for an RA/Dec offset, of course), but the displacement on anything attached to the rotator (TV, CCD, IPCS) will remain constant. All of the aperture offsets are calculated relative to a nominal aperture position which is specified in the system startup (.STD) file and corresponds to an easily visible reference position (the Grinnell crosswires or the centre pixel of an imaging CCD). This is because the reference position does not usually coincide with the rotator axis (which defines the origin of coordinates). The displacement between the reference position and the rotator axis (the base aperture offset) must be calibrated from time to time. For the INT at prime focus, the reference point is in the centre of the CCD chip (10 arcmin off-axis), but for the Cassegrain systems on both telescopes, SNAFU is usually done on the Grinnell cross wires so the reference aperture offset is set up to be the (small) difference between the turntable centre of rotation and the Grinnell cross-wires with the TV in the centre/acquisition position.


This command has been removed. See EQUINOX



sets up the telescope offsets in arcsecs in RA, Dec or both according to the qualifier. These are defined in a tangent plane projection centred on the current position of the telescope. The telescope begins to move as soon as RETURN is pressed. As the telescope moves to the OFFSET the autoguider automatically follows the reverse vector so that it does not lose the guide star.


has been replaced by DELETE.


has been removed.


D(EC) dd mm ss.s

enters the declination for the current edit source. The format is degrees minutes seconds. The seconds and minutes may be omitted but then the command must be terminated explicitly either by a carriage return or by a semi-colon. There are no qualifiers.


deletes sources from the catalogue according to the qualifier.

DEL(ETE)/F(ROM) source-name source-name

deletes the sources in the resident catalogue between and including the given source-names. If only one sequence number is given, only that source will be deleted.


deletes all sources in the resident catalogue except the first three; .DEFAULT, .GUIDE and .LINK .

DEL(ETE)/S(EQ) sequence-number sequence-number

deletes sources in the resident catalogue between and including the given sequence numbers. If only one sequence number is given, only that source will be deleted.


DIF(F_RATES)/B(OTH) RA-rate (sec/sec) Dec-rate (arcsec/sec)

DIF(F_RATES)/R(A) rate(secs/sec)

DIF(F_RATES)D(EC) rate(arcsecs/sec)

sets up differential tracking rates in RA,Dec or both (according to the qualifier). This will be actioned by pressing the DIFFERENTIAL TRACK button on the control panel. Note that this mode is switched off upon source change.


DIS(PLAY). This command is not yet implemented.


DO(ME) sets up the required dome azimuth. At present there is no button to action a dome move, so this command is nugatory.


ED(IT) Source-name

selects the given source as the edit source. There are no qualifiers


has been removed. No commands need to be enabled.


is not implemented.





sets up the mean co-ordinate system (B for Besselian or J for Julian) and the equinox (year) for the edit source. The equinox for apparent co-ordinates is assumed to correspond to the current date. FK4(B1950.0) and FK5(J2000.0) will eventually be supported, but at the moment only FK4 is implemented. This command combines the old EQUINOX, MEAN and APPARENT commands.


EP(OCH) year.y

This command is not yet implemented. For the time being the EPOCH is assumed equal to the EQUINOX.


F(OCUS) position (mm)

Sets the required focus position. The telescope focus will be driven to this value when the FOCUS-NOMINAL button on the control desk is pressed. The FOCUS-STOP button halts the focus drive. Once the focus drive has been set it will track to follow any change in tube temperature. There are no qualifiers.



slews the telescope to the NEXT or given source and initiates tracking.


is equivalent to the TS/DOME (SOURCE) button on the control panel. It slews the telescope to the NEXT source and initiates tracking.

GO(TO)/SO(URCE) source-name

slews the telescope to the named source and initiates tracking. NOT YET TESTED.


GU(IDE_OBJECT) guide-name

defines a guide object for the edit source by linkage to an existing entry in the catalogue containing the co-ordinates of the guide star. When the telescope is slewed to a new source and the GUIDE TO GUIDE-STAR button is pressed on the SYSTEM CONTROL panel, the probes will drive to the position of the guide object if it is at a position. This procedure is used when the co-ordinates of a guide star are known in advance. There are no qualifiers. This command is not yet working on the JKT.


HA(NDSET)/A(LL) set-rate guide-rate increment

HA(NDSET)/S(ET) set-rate (arcsec/sec) (0-75)

HA(NDSET)/G(UIDE) guide-rate (arcsec/sec)

HA(NDSET)/I(NCREMENT) increment (arcsec)

inputs the set and guide rates and the increment step to be actioned by the handset and the guide buttons on the control desk. The new rate or increment will not be effective until the corresponding SET/GUIDE/INCREMENT selector has been pressed.


H(ELP) Command

provides on-line help information about a specific command from the file USERHELP.TXT. There are no qualifiers.



inputs commands from a specified disc file or device.

I(NPUT)/N(ORMAL) file-name

This will normally be a catalogue file but may be a file of user-interface commands like GO and WAIT in order to set up an observing sequence. If no extension of the file-name is given then .CAT is assumed. If a large file is to be input it is advisable to pause the TNHZ task if the telescope is not tracking. This will speed up the input considerably.

I(INPUT)/PROMPT device name:

This is used on startup of the user-interface to select input from this terminal interactively.



will list the source names and coordinates from the resident catalogue.


will list the whole resident catalogue to the screen, pausing after each page to ask whether more output is wanted.

L(IST)/F(ROM) source1 source2

will list from source1 to source2 on the screen.


will list the whole resident catalogue to the line printer.


has been removed. See EQUINOX.


N(EXT)/NA(ME) source-name

N(EXT)/SEQ(UENCE) sequence-number

defines the next source to be observed, selected by name or sequence number according to the qualifier used. .DEFAULT is number 1, .GUIDE is number 2 and so on through the catalogue.


O(FFSET)/B(OTH) RA-Offset Dec-Offset

O(FFSET)/R(A) RA-Offset (arcsecs)

O(FFSET)/D(EC) Dec-Offset (arcsec)

sets up the telescope offsets in arcsec in RA,Dec or both (according to the qualifier). These are defined in a tangent-plane projection centred on the current position of the telescope. They are actioned by the control panel OFFSET button. The OFFSET NOMINAL button will return the telescope to the original position. The offsets in use are displayed on the information display.



This command is not yet implemented.



P(ROPER_MOTION)/R(A) RA (secs/year)

P(ROPER_MOTION)/D(EC) Dec (arcsec/year)

sets the proper motion of the edit source in RA,Dec or both. The corresponding epoch is assumed to be the same as the equinox. NOTE THE DIFFERENCE IN UNITS


R(A) hh mm ss.s

sets up the Right Ascension for the edit source. This format is hours minutes seconds. As with D(EC) the last two are optional but the command must be terminated with a semi-colon if they are omitted. There are no qualifiers.



This command is not yet implemented.


has been removed


Cannot be used on the JKT as the Turntable Rotator is not under computer control. See 3.3 for method of operating the Rotator manually.


SA(VE) Filename

saves the catalogue in memory to a user-specified disk file, which must have a .CAT extension, whatever extension was entered. There are no qualifiers.


SC(AN)/ALL duration length angle separation number

SC(AN)/D(URATION) total scan time (secs)

SC(AN)/L(ENGTH) length of line (arcsec)

SC(AN)/A(NGLE) position angle of line (degrees)

SC(AN)/S(EPARATION) separation between lines (arcsec)

SC(AN)/N(UMBER) number of lines in scan


Sets up the parameters of a raster scan. It is actioned by the control panel SCAN/TRAIL buttons as follows:

to start a scan press SCAN/TRAIL - START & CONTINUE

to pause a scan press SCAN/TRAIL - HOLD

to reverse a scan direction press SCAN/TRAIL - BACK

to stop a scan or return to the start position press SCAN/TRAIL - ABORT

Note that to select between SCAN and TRAIL (q.v.) press the SCAN/TRAIL button so that it is lit for SCAN and unlit for TRAIL; TRAIL is the default mode.


sets up various UI parameters according to the qualifier

SET/LST hh mm ss

sets up the Local Sidereal Time for use by the ADVISE command.

SET/UT hh mm ss

sets up the UT for use by the ADVISE command


ADVISE will use the current time (this is the default on startup)


has been replaced by an amplified ADVISE


sets up the telescope index errors or the aperture offsets.


sets the collimation and index errors.

The sequence of events is as follows:

  1. slew the telescope to an accurately-known source position;
  2. Type SN(AFU) and follow the instructions on the terminal i.e. press RETURN and ....
  3. use the set/guide/increment functions to position the object on a reference mark (either the Grinnell cross-wires or the centre of a CCD chip) - see APERTURE
  4. press the ACKNOWLEDGE button on the control panel.


The qualifiers /A and /B enable the different aperture positions to be recorded by the system for use by the BEAMSWITCH button.

The procedure is:

  1. set an object on the reference mark (see above) using the guide buttons or the handset;
  2. type SNAFU/A on the user interface console;
  3. move the object to the desired aperture position, again using the handset or desk buttons;
  4. press the ACKNOWLEDGE button and then BEAMSWITCH NOMINAL to restore the object to the reference position.

/B sets the aperture offset for beamswitch B in the same way.



defines a new entry in the source catalogue. The first three entries cannot be erased: .DEFAULT, .GUIDE and .LINK. A newly defined entry automatically becomes the EDIT source, so its parameters (RA, DEC etc.) can be entered immediately.

SO(URCE)/I(INPUT) source-name

This command provides the source with default values for RA, DEC, EQUINOX, co-ordinate type (MEAN or APPARENT) and PROPER-MOTION in both co-ordinates. The default values for all these quantities are copied from the source which is called .DEFAULT . This is the first entry in the catalogue and has its parameters set on start up. Until a new SOURCE command is issued, any commands which set or alter any of the above mentioned quantities will update the values associated with the 'source-name'.

SO(URCE)/M(ARK) Source-Name

This command provides values for RA,DEC, EQUINOX and co-ordinate type from the current position of the telescope: proper motions are set to zero. This provides the means to log the positions of objects with poor or unknown co-ordinates measured at the telescope. Until a new SOURCE command is issued, any commands which set or alter any of the above-mentioned quantities will update the values associated with the 'Source-Name'.


Checks are made to see if the source-name is already in the catalogue; whether the maximum number of catalogue entries has been exceeded; whether the storage allocated to the dictionary of source-names has been filled; or whether the name of the source is too long. Appropriate messages are displayed in each case and no catalogue entry is made.


Has been removed.



is the equivalent of the T/S Dome STOP button on the control panel. It stops both the telescope and the dome. There are no qualifiers.






is used to set the mode of telescope operation according to the qualifier; ie working either East or West of the pier. E(AST) is the default mode for the JKT. OVER and UNDER-POLE refer to the INT.



is only used for input from files. The text following the command is printed on the terminal. It is used for instance to output the initial messages for the user interface. There are no qualifiers.


TR(AIL)/ALL duration length angle

TR(AIL)/D(URATION) duration (secs)

TR(AIL)/L(ENGTH) length (arcsecs)

TR(AIL)/A(NGLE) position-angle (degrees)

sets up the parameters for a trail and is very similar to SCAN (q.v.). It is actioned by the associated SCAN/TRAIL control console buttons. For both SCAN and TRAIL, the starting position is where the telescope is set at the time the begins. There is no offset to a central position. The trail can be reversed, paused or aborted as with SCAN.


TU(RNTABLE) position angle (degrees)

Cannot be used on the JKT because there is no computer control over the turntable rotator.


has been removed.


is used to zeroset the incremental encoders.


sets the incremental encoder readings to zero when the telescope slews past a hardware marker. The sequence of operations is:

  1. Move telescope to within about a degree of the zero set position but not exactly on it;
  2. Press <cr> when ready to continue
  3. The green handset lamps on the control panel will light up
  4. Use the engineering-mode telescope control buttons to move the telescope through the zeroset position at the speed marked on the control potentiometers (about 1 deg/sec) in each of the coordinates successively. As each axis is zero-set the appropriate console light will go out indicating successful completion for that axis.
To get out of this procedure at any time, press the ACKNOWLEDGE button on the control desk. There are no qualifiers.


This replaces SET/ZERO but is not yet debugged. It is used when the hardware zeroset is broken. In this case, move the telescope to the zeroset position at the zenith (HA = 0; Dec = latitude) as indicated by the synchros (INT) or setting circles (JKT) and enterZ(EROSET)/M(ANUAL). This effectively does a SNAFU operation assuming that the telescope is at the zeroset position.


Character strings separated by spaces are entered at the User Console and sent to the programme USER by pressing RETURN. USER's command processor attempts to identify the first string as a command name by comparing it with its internal dictionary of such names. If it is successful in making a match, one of two things may happen: a command which does not take any arguments (e.g. GO) is executed immediately; however, if the command takes arguments (e.g. R(A)) the program will go on processing the input line until the requisite number of acceptable arguments have been analysed, when the command is executed. If the input line is not exhausted the next character string delimited by spaces is processed in the same manner. If the commandprocessor cannot match the character string with a command name, an error message is output and the rest of the line is ignored.

Many commands have qualifiers as well as parameters and some require the activation of a control panel button after the UI command has been entered. The full specification of a command could therefore be of the form:


followed by pressing a control panel button. Note that occasionally parameters are associated with only one qualifier.


This command displays the HELP information held in a set of modular hierarchical Help libraries in an interactive manner which allows a degree of browsing through the structure by the user. This facility is activated by entering the following command to the User Interface:-

HELP [/LIB(RARY)=libname] [item1 [item2 [... [item10] ... ]]

When the HELP command is active the user is prompted for further input to guide the search through the library structure:-

'prompt for input' item1 [item2 [... [item10] ... ]]

'prompt for input' command

Where the 'prompt for input' reflects the current position within the library structure.

HELP/LIBRARY = libname

The use of this parameter enables information held within libraries other than the default library to be enquired after. If this parameter is used it MUST be the first entry after the HELP command but it need not be separated from the HELP by a space. It will cause the Help Library with filename <libname> to be searched instead of yhe default library.

If this parameter is omitted, or <libname> is blank, then the default library TCS.HLB is assumed. If the "=" sign is also missing then the "/LIB.." which has been entered is assumed to be <item1>.


This is a standard Perkin Elmer file name of the form:-


vol a 1 to 4 character volume name

name a 1 to 8 character file name

ext a 0 to 3 character file extension

acct a 1 to 5 character numerical account

However the volume name and account number portions, if given, are ignored and the library is looked for in account 0 of the SYS volume. If the file extension is omitted then 'HLB' is assumed.


It is usually not necessary to use this parameter since the Help Library architecture supported by this software is modular and hierarchical and all the help libraries within the TCS and ICS can be reached via the default. Its only uses would be to refer to libraries not within the hierarchy (for example, private libraries or new versions of existing libraries) or to shorten the item search path, though this latter reason is not of particular importance.

item <n>

When entered as part of the HELP command this is the nth level enquired item relative to the initial HELP Library which is level 0. If no item is given then all topics at level 1 in the library are listed.

When entered in response to a prompt from HELP it is the nth level item below the current level. The maximum number of enquired items is ten.

Inputting a sequence of enquired items specifies a path down the HELP hierarchical structure from the current level. This path may fail at any point due to the non-existence of a particular <item> and in this case a warning message is produced together with a list of topics at the lowest valid level on the path. In addition, a separate log of such failures is maintained to give an indication of what HELP information , according to the user's perception may be lacking.


There are four single character commands which can be entered in response to a prompt from the HELP system:-

'?' list all topics below the current level

' ' move one level up the hierarchy - terminates HELP at level 0

'!' terminate the HELP command immediately

'-' move one level up the hierarchy (don't use)

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Tue Aug 5 05:37:08 MET DST 1997