2013/11/15
A postscript version of this document is available.
TCS is the online Telescope Control System developed by the Australia Telescope National Facility (ATNF). The system consists of
The TCS UI was written by Mark Calabretta, 1997-2012. It began life as tkmulti which was written by David Barnes, 1996-97. It is now maintained by John Reynolds and Mike Kesteven.
The controller was written by Michael Kesteven and more recently, John Reynolds.
One of these clients, referred to as ``ctrl'', handles normal
communications and the other, ``intr'', handles out-of-band
messages such as [STOP ...] (p![[*]](crossref.png)
) requests.
The rest of this manual is primarily concerned with the TCS GUI, the graphical aspect of the TCS UI.
TCS is capable of running on Sun workstations under Solaris, or on Debian Linux (32 or 64 bit architecture). At Parkes it is now run mostly on the virtual Linux hosts 'joffrey' and 'myrcella', under the user account 'pksobs'.
At Mopra TCS runs on the Linux host 'bigrock' under the user account 'atcaobs'
Ensure that the DISPLAY environment variable is correctly set before starting, e.g. with setenv DISPLAY :0.0 (this is not normally required). Then type tcs to start the TCS GUI.
The startup menu also offers the following options:
This option enables all configurations, so, for example, someone at Parkes could do remote observing at Mopra. The name of the remote host that will run the controller needs to be specified. The version of TCS to be used can also be specified but should normally be left at the ddefault value.
The user account needs to have remote Glish client invokation enabled to use this facility.
Note that remote observing at Parkes does not use this feature but instead uses VNC, with TCS runing inside a VNC session on the observing server (joffrey).
This mode is useful for preparing observations ahead of time or while another instance of TCS is running the telescope.
Lastexit file names are composed of a project identifier and name. The
button with a ``right-arrow'' is connected to a filebrowser (p) which
allows a particular lastexit file to be selected.
Un-selecting this option will instruct TCS to start with 'vanilla' default values.
The main TCS GUI starts when the [OK] button is pressed in the startup menu and it should greet you with the sound of a Laughing Kookaburra. Its initial actions can be monitored as output in the terminal window in which it was started and also in the TCS GUI's log window. These actions are to load the last exit state (if required), then load the parameters for the configuration selected, and then start the controller and communications clients.
The controller will check to see that there aren't any other instances of TCS running and then initialize itself. You should check that it and the communication agents have successfully established themselves.
If another instance of TCS is found the controller will issue an appropriate warning and instruct the user to type "control-C" in the start window to kill the TCS GUI .
This section describes general features of the TCS GUI.
To copy and paste text, first position the i-bar at the start point of the text to be copied; press the left mouse button and then drag the i-bar to the end point. The selected text will be highlighted. It may then be pasted elsewhere by positioning the i-bar at the required insertion point and pressing the middle mouse button.
Note, however, that some widgets may not be write-enabled for text insertion (e.g. the logger window).
The middle mouse buttons is used to paste text.
The right mouse button is not used.
Do not confuse this with copying and pasting text - it is the listbox entries which are selected rather than the text they are composed of.
Note, however, that multiple entry selection is only enabled for listboxes
where this makes sense (e.g. the catalogue browser within the
skyviewer (p)).
Keyboard focus is retained when the cursor is moved away provided that another widget does not gain the focus in the process.
Characters can be typed into an entry box when it has keyboard focus.
When a button has keyboard focus pressing the SPACEBAR or RETURN key effects a button press.
A scrollbar or slider can be manipulated via the arrow keys when it has keyboard focus.
When an entry box obtains focus via this method its contents will appear highlighted and will be replaced by the next keystrokes.
The TCS GUI uses stylistic features consistently:
This manual can be accessed within Netscape by clicking the
[HELP] (p) button in the top right-hand corner of the TCS GUI. It can
also be displayed by clicking on any of the seven blue labels in the TCS GUI
in which case the browser will scroll to the relevant section of the manual.
Strings typed into entry boxes are converted internally to their proper type.
For example, a frequency in MHz entered as ``1720.5300'' (OH radical) would be
stored internally as a double precision value,
. For
display purposes this would be reformatted as ``1720.5300''; note that the
number of significant decimal digits is preserved.
As an example of parameter validation, a zero or negative frequency would not be accepted. The following error message would appear on the terminal where TCS was invoked in response to an attempt to set the frequency to zero
Invalid parameter assignment (<= 0):
ignored [freq1 = 0] (double type)
remains [freq1 = 1720.53] (double type)
23h57m17.330s +359d19'19".95
23h 57m 17.330s +359d 19' 19".95
23h57 17.330 +359d 19 19.95
23h57:17.330 +359d 19:19.95
23h.954814 359d.32221
23.954814h 359.32221d
-00h02m42.670s -0d40'40".05
-2m42s.670 -40'40".05
-2m42.670s -40'40.05"
-2m42.670 -40'40.05
-0h.045186 -0d.67779
-0.045186h -0.67779d
Moreover, in a context where a time value is expected, e.g. right ascension, the following generic sexagesimals would be equivalent to the above:
23:57:17.330
23: 57: 17.330
23 57 17.330
23.954814
-00:02:42.670
-00 02 42.670
-0.045186
On the other hand, in a context where an angle in degrees is expected, these generic sexagesimals would be interpreted as an angular quantity in degrees, minutes and seconds.
Whether the TCS UI accepts a sexagesimal angle or time or both depends on the particular parameter. For example, while it is permissive in accepting longitudes (right ascension, hour angle, azimuth and galactic longitude) as either a time or an angle, it rejects latitudes specified as a time as being non-sensical.
Angles and times specified in sexagesimal notation are all converted
internally to degrees as a double precision value. For some parameters the
value may be normalized in an appropriate range, e.g. ![$[0,360^\circ]$](tcs_img2.svg)
for
right ascension or
![$[-180^\circ,180^\circ]$](tcs_img3.svg)
for hour angle. For others the
value is validated against an allowed range, e.g.
![$[-90^\circ,90^\circ]$](tcs_img4.svg)
for a
latitude. For display purposes these values are formatted as sexagesimal
strings of the appropriate type with the requisite decimal precision. For
example, the generic sexagesimal, 23:57:17.330, when entered for a
right ascension would be stored internally as 359
.32221 and displayed
as 23h57m17.330s. When entered for a declination it would be stored as
23.954814 and displayed as 2357'17".330 (n.b. with a
proper degree symbol). This should make it clear how the TCS GUI has
interpreted the sexagesimal value.
The TCS GUI has a number of auxiliary browsers, viewers, and miscellaneous graphical utilities. Usage of most of these is self-evident but a few have features which require further explanation.
File selection, whether of existing files or files which are to be created, is
accomplished by means of the filebrowser utility. It appears from
within the schedule file editor, scheditor (p), skyviewer (p), and
startup menu (p) as well as from various places within the main TCS GUI.
The filebrowser displays the contents of the directory whose name is displayed in the entry box at the top of the browser. Clicking on the [Dir] button causes the list to be updated.
Directory listing options are provided by the [Options] menu button in the bottom left corner. This provides for a long directory listing, full directory listing (i.e. of dot-files), and forward or reverse sort on a choice of sort keys including the file name and last modification time.
A file may be selected by a single, left-button mouse click followed by clicking on the [Okay] button, or simply by a double mouse-click on the file name.
Once a file is selected the browser normally disappears but this can be circumvented by checking the [Stay up] button. The browser may be dismissed at any time without making a selection via the [Dismiss] button.
The filebrowser usually allows directory navigation but may sometimes appear with this disabled. If navigation is enabled the entry box at the top of the browser will be enabled for input and it may be used to enter a directory pathname. This may be either absolute or relative to the current directory, if relative it will be replaced with the corresponding absolute pathname.
If directory navigation is enabled the parent directory and all subdirectories will appear with a trailing slash within the directory list. Single-, or double-clicking on one of these entries effects the change of directory.
In file-creation mode the filebrowser contains a [File] entry box for keyboard entry of a new file name. A file name selected by single-clicking on the directory listing will be copied to this entry box and may be modified if desired.
The infoviewer logs time-stamped values. A value is either a simple message string or a keyword/value pair, the value of which may be updated at a later time. Each of the five telescope subsystems, antenna, focus, local oscillator, attenuator and correlator has a pair of infoviewers, one for diagnostics and the other for informational purposes.
The recordbrowser displays the contents of files which contain information in tabular format and allows an entry or range of entries to be selected. It is used, for example, to view and select entries from source and frequency catalogues.
The recordbrowser displays the contents of the file whose name is given in the entry box at the top of the browser. Clicking on the [File] button causes the list to be updated.
A record may be selected by a single, left-button mouse click followed by clicking on the [Okay] button, or simply by a double mouse-click on the file name. Normally only one entry may be selected but in some cases the browser may be enabled for multiple input. A range is selected via left mouse-button click-and-drag, or click-SHIFT-click. The [Okay] button must be used to accept the selection in this case.
If the [Info] button is enabled it provides access via a
textviewer (p) to explanatory material in the header of the file.
Once an entry is selected the browser normally disappears but this can be circumvented by checking the [Stay up] button. The browser may be dismissed at any time without making a selection via the [Dismiss] button.
Very large files are displayed in multiple ``chunks'' of about 3000 entries each. If a file has been dissected in this way a slider will be provided to move between chunks.
The recordbrowser may appear with [Next] and [Prev] buttons if it was invoked on multiple input files. This may happen to display the result of a catalogue search if a source is found in more than one catalogue.
The remhost window only appears when the TCS GUI starts up for remote observing. It allows the observer to specify the name of the remote host on which to activate the controller.
The schedule file editor, scheditor (p), is a special purpose
graphics-based editor designed explicitly for creating and modifying schedule
files. It is described in detail in §12.
The skyviewer (p) window provides an interactive, graphical
representation of the sky providing point-and-click control of the telescope.
It is described in detail in §11.
The startup menu (p) has already been described.
The textviewer is a simple, resizable, utility for displaying text. It
is used by the TCS GUI for such things as displaying the latest news and (via
the recordbrowser (p)) the explanatory prologue to the source and
frequency catalogues.
An orange-coloured warning popup appears if any of the telescope subsystems is disabled. These serve only to reinforce the orange warning status indicated for the subsystem on the TCS GUI.
When the [Exit] button is pressed on the TCS GUI a small confirmation
window appears. This also contains a checkbox which indicates the name of the
lastexit file and provides the opportunity to exit without saving state.
)
configurations.
). There are two basic observation modes:
tracking, in which the telescope follows a fixed coordinate, or
scanning, in which it moves uniformly from one coordinate to another.
At the most basic level the [Source name] menu button and entry box simply provides a means of setting the name of the source to be recorded in the OBJECT card in the output RPFITS file.
However, the menu button also provides access to source catalogue lookup and search facilities.
~/tcs/catalogues).
Selecting either of these options will invoke a filebrowser (p) on the
selected directory. If a catalogue is selected it's explanatory prologue will
appear within a textviewer (p) and the catalogue contents made available
for perusal within a recordbrowser (p). If a selection is made the
relevant information is extracted and the TCS GUI widgets updated:
Note that this facility provides a convenient means of using source lists prepared in advance. Such lists (catalogues) may be stored in either of two ways:
record-format: 58 75 1:8 11:20 28:36 B1950 0
The fields are interpreted as follows:
) menu button)
There follows a nest of radio buttons which specify which source catalogues are to be used for the lookup:
~/tcs/catalogues).
Typically a source will be found in several catalogues, a message will appear
in the log window indicating the number of matches found. Each entry will be
displayed in turn in a recordbrowser (p) which in this instance will be
equipped with [Prev] and [Next] buttons to allow navigation between
catalogues.
Note that grep-type regular expressions may be specified for the source name in auto-lookup mode. The expression in the entry box will be replaced by the name of the source selected. This provides a very powerful source selection capability.
Note that changing the coordinate system does not cause the coordinates to be
transformed but may affect normalization and formatting (see §1.2.5). For example, an angle displayed as 18h02m42.669s for a
right ascension will be displayed as -05h57m17.331s for an hour angle,
or 27040'40".04 for a galactic longitude.
The [Observation type] menu selects from two basic classes of observation, tracking and scanning. Tracking-type observations, with parameters described in §3.4, are:
Only one scanning-type observing mode is currently defined; its parameters are described in §3.5:
The scan end-points may be defined directly, or indirectly by specifying the start point and scan length, or the scan centre and scan length.
Other observing modes which may be added in future are:
As a reminder, the type of observation selected is reflected in the label of
the [Start] (p) button, for example, [Start TRACK].
) menu button. Optional position offsets
(§3.4.2) may be applied to this fiducial position.
The [Catalogue position] menu button reveals a [Lookup from source
name] button which is the one-shot version of [Automatic source
lookup] (p).
Two separate offset types are provided, [SIGNAL] and [REFERENCE]; ``S'' is appended to the field name for signal offsets and ``R'' for reference offsets.
When a [SIGNAL] or [REFERENCE] offset is selected the relevant widgets will be colour-coded as a warning that a position offset is being applied.
before being
added to the longitude of the fiducial point.
) button in tracking modes.
) button in
tracking modes.
before being
added to the longitude of the start or centre point.
The Parkes telescope, with its prime focus translator system, usually has several available, but at Mopra and elsewhere only one may be installed at a time.
In some startup (p) configurations this item may allow input for
focussing control. In others it may serve only to display the value reported
by the controller. The type of entry box border will indicate which.
)
configurations. It specifies the beam to use as the pointing reference in
multibeam observations, i.e. the beam which points to the source.
If set to anything other than 1 a warning will be issued and the background of the entry box will turn orange as a reminder.
) configurations.
In some startup (p) configurations this item may allow input to control
the beam orientation. In others it may serve only to display the value
reported by the controller. The type of entry box border will indicate which.
Total power mode is set automatically for some settings of
[Observation type] (p) such as [MXCAL]. Otherwise, setting total
power mode will change the label on the [Start] (p) button from, for
example, [Start TRACK] to [Start calTRACK] as a reminder that the
correlator is not in its normal setting.
The [Generate filename] and [Decode filename] menu items provide one-shot options to generate or decode the configuration file name if [Auto-generate] or [Auto-decode] are not enabled.
) and number of
[Channels] (p) as set in the [LOCAL OSCILLATOR] (p) panel whenever
they change.
If no configuration file matches the selected parameters then a warning will be issued and (unavailable) will appear in red in the [Configuration file] entry box.
) and number of [Channels] (p) in the
[LOCAL OSCILLATOR] (p) panel.
The [LOCAL OSCILLATOR] panel contains two separate sub-panels, one for each of two LO systems, at least one of which must be enabled at any time. If only one LO is enabled and it is disabled via the check button at the top of the sub-panel then the other will be enabled automatically.
If [Auto-generate] (p) is enabled in the [CORRELATOR] (p) panel then
the correlator configuration file will be updated as LOs are enabled or
disabled.
Alternatively, if [Auto-decode] (p) is enabled in the [CORRELATOR]
panel then LOs will be enabled or disabled appropriately whenever the
correlator configuration file is changed.
It is important to realize that Doppler tracking is not performed during the course of an observation; the LO system is configured for a particular frequency at the start of an integration and thereafter remains unchanged. The Doppler correction simply ensures that the frequency of interest falls near the middle of the bandpass being observed. Topocentric velocity effects are assumed to be negligible over the timespan of an integration.
If the frequency specified is the rest frequency of a radio line then one would normally select [REST] to have the Doppler correction applied so that the line falls near the centre of the band. On the other hand, surveys with fixed frequency limits such as HIPASS and ZOA would select [SKY] to disable it.
The standard catalogue was constructed from the NIST (Lovas, 1991) database of molecular line frequencies augmented with a small set of hyperfine transitions for hydrogen, helium and sodium, as well as the full set of hydrogen recombination lines for the alpha, beta, gamma, delta and epsilon transitions computed from the Rydberg formula in the range 0.3 - 120 GHz. Full details are provided via the [About spectral line catalogues...] menu item.
The standard catalogue is large so for practical reasons it has been dissected in three ways, [By frequency...], [By molecular formula...] and [By molecular name...]. Each of these sub-sub-menu items invokes a filebrowser and subsequently a recordbrowser to select an entry from the catalogue.
Users may maintain their own frequency catalogues in the
~/tcs/lines directory. The frequency is extracted from the
first field of the record, additional fields may be used as comments to
identify the line.
The line rest frequency is extracted from the catalogue into the [Frequency] entry box of whichever LO sub-panel(s) are enabled. To set the two LOs to different frequencies one must temporarily disable one and enable the other.
) configurations.
If [Auto-generate] (p) is enabled in the [CORRELATOR] (p) panel then
the correlator configuration file will be updated whenever this value is
changed.
Alternatively, if [Auto-decode] (p) is enabled in the [CORRELATOR]
panel then this value will be updated whenever the correlator configuration
file is changed.
, where the odd channel arises as the result of the
complex-to-real FFT performed by the AT correlator (i.e. not as a
``channel-0'' containing the integrated spectrum). Allowed values may be
restricted by particular startup (p) configurations.
If [Auto-generate] (p) is enabled in the [CORRELATOR] (p) panel then
the correlator configuration file will be updated whenever this value is
changed.
Alternatively, if [Auto-decode] (p) is enabled in the [CORRELATOR]
panel then this value will be updated whenever the correlator configuration
file is changed.
The [Channels recorded] menu contains check buttons [Always record all #1] and [Always record all #2] which, if enabled, ensure that all channels will be recorded. If disabled, a pair of entry boxes are provided in the relevant LO sub-panel to allow a channel range to be specified. A ``0'' specified for the end channel range means the last channel.
While observing the current frequency will be notified for each LO chain in
the [Freq 1] (p) and [Freq 2] (p) status values in the
[SYSTEM STATUS] (p) panel.
) value via the
[Frequency offset] entry box.
) is selected in the [REST/SKY] menu, the spectral range
will be centered on the Doppler-shifted value of the frequency specified in
the [Frequency] (p) entry box. Otherwise, for [SKY] (p), it will be
centered on the value as given.
The Doppler shift is computed for the source velocity specified in the [Velocity] entry box; the velocity is positive if the source is moving away from the observer. The reference frame for which this velocity was computed and the nature of the velocity convention may be specified via the [Frame] menu ([LSR-KINEMATIC], [LSR-DYNAMIC], [BARYCENTRIC], [GEOCENTRIC], [TOPOCENTRIC]) and the [Convention] menu ([RADIO], [OPTICAL], [RELATIVISTIC]). Typically this information comes from a source catalogue. Of the two Local Standards of Rest (LSR) the kinematic reference frame is the one more frequently used.
If an [LSR-KINEMATIC] source velocity is specified, the Doppler velocity
will consist of this minus the component of the observer's LSR-kinematic
velocity towards the source. The observer's LSR-kinematic velocity is the
vector sum of the 20 km/s velocity of the barycentre towards
(J2000), plus the
30 km/s orbital velocity of the earth around the barycentre, plus the 0.5 km/s
rotational velocity of the earth on its axis.
If an [LSR-DYNAMIC] source velocity is specified, the Doppler velocity
will consist of this minus the component of the observer's LSR-dynamic
velocity towards the source. The observer's LSR-dynamic velocity is the
vector sum of the 16.6 km/s velocity of the barycentre towards
(J2000), plus the
30 km/s orbital velocity of the earth around the barycentre, plus the 0.5 km/s
rotational velocity of the earth on its axis.
If a [BARYCENTRIC] source velocity is specified, the Doppler velocity will consist of this minus the component of the observer's barycentric velocity towards the source. The observer's barycentric velocity is the vector sum the 30 km/s orbital velocity of the earth around the barycentre, plus the 0.5 km/s rotational velocity of the earth on its axis.
If a [GEOCENTRIC] source velocity is specified, the Doppler velocity will consist of this minus the component of the observer's geocentric velocity towards the source. The observer's geocentric velocity consists only of the 0.5 km/s rotational velocity of the earth on its axis. This frame might be appropriate for observing an object in the solar system.
If a [TOPOCENTRIC] source velocity is specified, the Doppler velocity will consist of this alone. This is effectively the same as switching Doppler tracking off (i.e. selecting [SKY]), except with a constant, velocity-based shift of the frequency range.
The velocity conventions are defined as follows:
where 
is the measured line frequency, 
is the line rest frequency
and 
is the velocity of light.
If the velocity was obtained from a radio catalogue then it will almost invariably have been computed via the radio convention. This convention is used in radio astronomy because the channels of a radio spectrum are usually spaced uniformly in frequency. Thus, the radio velocity, being proportional to the frequency shift, forms a linear scale on these spectra.
On the other hand, optical spectra are usually spaced uniformly in wavelength. For these the optical velocity, based as it is on the wavelength shift (redshift), forms a linear scale.
In general, the radio velocity is a much better approximation to the
relativistic velocity than is the optical velocity which diverges for
relativistic velocities approaching the speed of light. However, for
velocities below about 
there is not much difference between any of
them.
As explained previously, the Doppler correction simply ensures that the
frequency of interest falls near the middle of the bandpass being observed.
The spectra are always labelled with the actual observed (i.e. sky or
topocentric) frequency. Thus in most cases little harm would be done to
specify a slightly incorrect velocity or to use the wrong reference frame or
convention.
The [PULSAR BACKEND CONTROL] panel...
Generally the [ACTION PANEL] contains buttons for controlling an observation based on the parameters set elsewhere in the TCS GUI.
) to present news about the
latest developments to TCS.
A third menu item, [PostScript], invokes gv to display the POSTSCRIPT form of the manual which, while generally better formatted, lacks hypertext cross-references.
As a reminder, the [STOP ...] button is labelled with the action currently in progress, for example [STOP TRACK].
[STOP ...] is implemented as a check button which is active when a stop request is scheduled and deactivated once serviced.
As a reminder, the [Start ...] button is labelled with the value
currently selected in the [Observation type] (p) panel, for example
[Start TRACK].
The crack of an Eastern Whipbird signals the end of the observation.
[Start ...] is implemented as a check button which is active when a go request is scheduled and deactivated once serviced.
[Drive] is implemented as a check button which is active when a drive request is scheduled and deactivated once serviced.
)
configurations
[Tsys] is implemented as a check button which is active when a mm_tsys request is scheduled and deactivated once serviced.
[Stow] is implemented as a check button which is active when a stow request is scheduled and deactivated once serviced.
This is not usually required. The TCS GUI checks all parameter values on entry, and all widgets are read and their values passed to the controller before any action is performed.
The [Sched] entry box can only be changed via a filebrowser (p)
which can be activated directly via the [Sched] menu (or indirectly
via the scheditor (p)):
~/tcs/sched).
) to edit the sched file whose
name is currently displayed.
As in most invokations of the filebrowser (p) directory navigation is
allowed. However, unlike most, a changed sched directory will be remembered
the next time the browser is invoked.
[Start sched] is implemented as a check button which is active while the schedule file is running and deactivated once it has finished.
The carolling of Australian magpies signals that the controller has finished executing the schedule file.
A row of coloured status indicators shows at a glance the overall status of the various telescope subsystems:
) also appears as a
reminder. This serves only to reinforce the orange warning status and can
safely be dismissed.
A warning is also recorded in the log which is accompanied by the scream of a Rufous owl.
Timestamped diagnostic messages are accumulated for display in an
infoviewer (p) which will be invoked automatically when an error is
signalled.
The subsystem status indicators are actually menu buttons which provide the following options:
) to display timestamped
diagnostic messages.
) to display timestamped
informational messages received from the controller. These may consist of
startup (p) parameters and other general information about the
subsystem.
) status display
provides more information on what the antenna is currently doing.
).
).
) configuration
file. The observatory longitude for the LMST comes from the startup
configuration file, or if this was not specified, Greenwich mean sidereal time
is reported instead. The clock should be accurate to within a few seconds.
During slow frequency these will be seen to toggle between signal and reference. However, in fast switching this would become a blur so it is shown simply as FAST.
While the verbosity of the log window may be controlled to some extent via
options in the [Utilities] (p) menu, all messages are recorded in log
files with names of the form ~/tcs/logs/YYYY-MM-DD.tcs.log.
These serve as a detailed observing logs, but note that log files more
than five days old are deleted when the TCS UI starts up. Thus to preserve
the log file it must either be renamed or copied elsewhere.
The TCS controller maintains separate log files in /nfs/online/logs/ with names of the form YYYY-MM-DD.tcs_ctrl.log. These contain timstamped entries which include some of the lower-level commands sent to the various telescope subsystems.
The TCS UI and controller log files are occasionally required either separately or in combination for debugging purposes.
) (with directory navigation disabled) to specify
a file in which to save the current parameter settings.
) (with directory navigation disabled) to specify
a file from which to recover parameter settings.
) the name and value of all messages sent to
the controller (such messages are always recorded in the log file). Messages
sent via the normal communications channel are labelled ``ctrl''
while those sent via the out-of-band channel are labelled ``intr''
(interrupt).
) the name and value of all messages received
from the controller (such messages are always recorded in the log file).
) (all messages are
logged to file). Mutually exclusive options are presented as a nest of radio
buttons:
) (not the file).
A Boobook owl obligingly calls as the slider is adjusted so as to indicate the volume.
The command travels via the normal communication channel and hence is queued behind any outstanding requests.
) to confirm or cancel exit from
the TCS GUI.
Beware that exiting the TCS UI also kills the controller and doing this while
an observation is underway may have undesirable consequences!
The skyviewer window provides an interactive, graphical representation
of the sky13 as
currently seen by the telescope. It employs a cylindrical equidistant (plate
carrée or ``Cartesian'') projection scaled so that equal distances in 
and 
correspond to equal drive times in azimuth and elevation. The azimuth
range extends beyond the conventional 
to cover the full azimuth
drive range of the telescope and azimuth wrap information is preserved.
The sky plot shows the current position of the telescope and of the sun and allows general sources to be plotted - either via manual entry of equatorial coordinates or by extraction from catalogues.
Aside from being a valuable display tool, the skyviewer can also be used to control the telescope directly, either by selecting the source of interest or by dragging the telescope marker. Source sequences may also be defined for semi-automatic operation.
have negative wrap with positive wrap in the range
.
Wrap ambiguity may arise when the current source is set by entering equatorial coordinates in the entry boxes or by selecting a single source from a catalogue. Should this source become visible on both wraps the rule to determine which wrap is chosen may be selected from the following nest of radio buttons in the [Wrap ambiguity] sub-menu:
When a source is chosen by selecting it with the mouse the wrap selection is honoured explicitly.
The [Zoom/pan] sub-menu provides control over zooming and panning:
The skyviewer maintains an internal source list whose positions are plotted on the sky map. In its initial state the menu button labelled [New source] solicits user input to define source parameters. Although manual parameter entry is possible the most convenient interface is via predefined source catalogues.
Clicking on one of the source markers with the left mouse button makes it the [Current source], a blue halo is drawn around the source marker and its parameters are copied into the entry boxes: name, right ascension, declination, equinox (J2000 or B1950), and radial velocity (km/s). These parameters are also downloaded into the main TCS GUI. The drive time to the source from the current telescope position is also displayed and a set of action buttons appears providing the option of driving to the source or observing it.
The telescope marker may also be dragged with the mouse and in this case the menu button is relabelled [Drive to] with the field coordinates and drive time shown in the entry boxes.
Source selections are plotted in the skyviewer window and added to the internal source list. If a single source was selected from the catalogue it automatically becomes the current source.
The sort order only makes a difference to the order of the sources shown in the source browser.
Once a sequence has been defined it can be run, i.e. each source in the sequence is observed in turn. Once a sequence is running it can be discontinued meaning that the sequence will stop after the current source has been observed. Once discontinued, a sequence may be resumed from the next source.
A light green line connects sources in the sequence which have yet to be observed. This portion of the sequence may be edited. The portion of the sequence which has already been observed is indicated with a dark green line. This part may not be modified.
The sequence list browser is indispensible when the sequence contains loops and/or repetitions.
) button in the [Options] (p) menu.
[Discontinue]: stop the sequence after the current source has been
observed. Use the [STOP ...] (p) button on the main TCS GUI to effect
an immediate halt.
[Resume]: resume a sequence which was discontinued, starting with the next source. Colour coding of the sequence path in the skyviewer window shows how much has been observed.
The schedule file editor is a special purpose graphics-based editor designed
explicitly for creating and modifying schedule files...
The schedule is intended to mimic the operations on the GUI - you enter some new fresh parameters (eg, a new source position), and launch operations (e.g., a scan). Any GUI command can be included in the schedule. Once a schedule has been invoked ("start") the schedule maintains control of TCS, shutting out most of the user-selectable functions of the GUI.
The essential point to grasp is that the schedule operates in an incremental fashion - it need only change a few operating parameters before launching a fresh scan. The down-side is that you need to be sure that unspecified parameters are indeed what you expect.
When a schedule is started, the current GUI's parameter set is sent to TCS. These provide the initial set; the schedule then replaces as much or as little as it wishes.
A schedule contains a loose mix of parameters and actions; these are grouped in UNITS. The recommended procedure is to make each unit self-sufficient; each unit may contain a number of actions, and each action will be governed by all the parameters between the start of the unit and the action.
TCS reports the number of actions and units in a schedule; the schedule pointer increments on data collecting actions, not units. It is therefore in practice simpler to write schedules containing precisely one action per unit (though unit-based incrementing may be introduced in the future).
When the user requests TCS to start an observation by clicking on the "start TRACK"/"start SCAN" button on the main action panel (without using a schedule), TCS reads all the parameters from the GUI and uses these to define the observation.
When a schedule is used, by clicking on the "Start sched" button, TCS first reads all the GUI parameters, then steps through the schedule from the nominated starting point. Any parameter defined in the schedule will therefore override the GUI value. Further, the value displayed on the GUI will be immediately reset to the value defined in the schedule, so the new value persists indefinitely (until explicitly changed). Thus the GUI should represent accurately the parameters of any observation currently in progress. (If this fails to occur it is a reportable bug!).
A further important consequence of this model is that parameters not specified by the schedule will default to the value displayed on the GUI. This is important to bear in mind, particularly at the start of an observing session. Unintended settings on the GUI inherited from a previous observing session can be disastrous if not detected by careful checking!
An observer can use TCS without ever using a schedule. For example, a series of repeated or similar simple observations of a list of sources might be accomplished more easily from the GUI alone, loading the source details from a user-prepared catalogue. This is the most interactive but also the most flexible style of observing.
The next level is to write a "minimalist" schedule containing only those commands which change from one observation to the next (e.g. source details) and use the GUI for fixed parameters or those which change only occasionally (e.g. correlator configuration etc).
Alternatively, an observer can "play it safe" and include every relevant setting in the schedule file. This gives protection against inheriting unwanted settings.
A hybrid scheme is to define all or most of the relevant parameters in the first "unit" (integration) of the schedule, and thereafter specify only changes to parameter settings (rather than repeating them for every integration). This can be a very convenient mode of observing, but beware of re-starting a schedule midway through after an interruption - any GUI parameters that have been changed in the meantime may not get reset if you skip the first integration of the schedule.
A schedule contains parameters (list A), immediate actions (list B) and OBS actions (= data collecting actions (list C).)
The parameters are keyword defined; for example:
The immediate actions are keywords - for example :
The OBS actions require two steps:
define the action:
obstype = action (eg, scan)
launch it :
go
Any schedule line beginning with the characters "#" and "!" is treated as a comment and ignored. Blank lines are also ignored. Comments can also be appended to a schedule line after a "#" or "!" character, eg;
doppler = T ! Turn Doppler tracking ON
The coordinate input machinery was designed for a more relaxed time, with command line entry. Many options are available, now probably irrelevant. The coordinate keyword contains implicitly the coordinate frame (j2000/b1950/galactic/hadec/azel), and also defines the way the input is to be interpreted -
raj=12.5 J2000 frame; value is in hours. az=180.5 AZEL frame; value in degrees.
Internally the values are all stored as degrees; defining explicitly the frame will override any previous implicit definitions - for example, az=180.75, el=21.5 and epoch=j2000 will define a source position as ra (j2000) = 12:03:00, dec(j2000) = 21:30:00. Common sense should prevail - keep it simple. The entries can be a decimals, formated angles (or hours), or with the units explicitly set. So the following are equivalent:
ra = 12:30:00.0 ra = 12.5 ra = 12h 30m ra = 187.5d
When mapping a region with long integrations at a number of different points it is convenient to define a central position (with ra/dec), and then use:
and remembering
,
and
on the celestial sphere, to move
the telescope 
in RA, the offset used is 00:00:01. TCS applies the
factor to the specified angle then adds it to the nominal
RA to get the target RA.
Scans can be defined in one of two ways:
Centre-Range; Use ra/dec/epoch for the centre and dra/ddec for the range (this is the full extent of the scan). Note that there is no 1/cos(dec) correction!
Start/End points: You add a suffix to the coordinate keywords - 1 for the start, 2 for the end. Use ra1/dec1 for the start, ra2/dec2 for the end.
In the STEPPED mode, the platform is rotated just before a scan starts, so it is exactly in the right orientation at mid-scan. BEAMTRK does a position tweak every 5 seconds during a scan, ensuring that the platform stays close to the scan axis all the time (good for scans near the south pole). BEAMTRK is essentially the same as CONTINUOUS, but with the addition that it does the hard work of determining the actual track on the sky during a scan, and positioning the platform relative to that axis (rather than the latitude lines, for example).
This item is important (and increasingly so) - it will cause the FCC to move a receiver on-axis; it defines the pointing parameters; it defines the focus platform tracking; it defines the conversion chain operation.
Launch a schedule file :
$ unit 1 !- define a new scan
freq = 1394.5 !- frequency in MHz
config = mb13 !- correlator mode (13 beams, 64MHz BW, 2048 ch)
bandwidth = 64 !- bandwidth in MHz (done above, but just to be safe)
fcc_p_trk = disabled !- no parallactification
source = 1934-638 !- source name
cycles = 5 !- number of 5 sec cycles
raj = 294.8543d !- RA(J2000) in degrees
decj = -63.71267d !- DEC(J2000) in degrees
fcc_rot = 0.0000 !- Receiver rotation angle
calibrate !- execute calibration
refbeam 1 !- returns reference beam to beam 1
! (done by calibrate, but repeated here to be sure)
disable refbeam !- disables reference beam mechanism (ditto).
$ unit 1 !- define a new scan config = mb7_8_2048 !- correlator mode (inner 7 beams, 8MHz BW, 2048 channels) fcc_p_trk = continuous !- parallactic tracking in continuous mode bandwidth = 8 !- bandwidth in MHz (done above, but just to be safe) freq = 1419.00 !- observing Frequency in MHz fcc_rot = 19.10 !- receiver rotation angle frsw = ON !- frequency swithching enabled dfrqsw = 3.125000 !- frequency swithing range obsval = 115 !- integration time... obsunit = seconds !- in seconds source = P355_G245a !- project ID _ source name fitsname = P355_G245a.mbf !- output \RPFITS\ file name raj1 = 121.50d !- RA(J2000) start in degrees decj1 = -29.50d !- DEC(J2000) start in degrees raj2 = 118.75d !- RA(J2000) end in degrees decj2 = -29.50d !- DEC(J2000) end in degrees scan !- start the scan from (raj1,decj1) to (raj2,decj2) closef !- close the correlator file
In this example, we want to map around a source with a spacing of 30" with a
reference position 30' to the east. Firstly, the telescope is driven to a
reference position relative to the source ($unit 1). Next, the telescope
goes back to the source position ($unit 2), and then offsets to the south
($unit 3), east ($unit 4), north ($unit 5) and west ($unit 6) before
returning to the reference position ($unit 7). Note that signal offsets
in RA are 00:00:02 (30"), and reference offsets in RA are 00:02:00 (30
)
(see §13).
$ unit 1 raj = 18:18:55.34 !- RA (J2000) of main source decj = -13:51:46.51 !- DEC (J2000) of main source source = M16 !- receiver = K-BAND !- freq = 22235.077 !- main frequency in MHz bandw = 32 !- bandwidth in MHz chans = 1024 !- 1024 channels vel = -200.0 !- velocity of source frame = LSR-dynamic !- velocity frame conv = Radio !- doppler convention average = 12 !- average 12 cycles before dumping to file source = Off !- label the position as reference srcoff = REFERENCE !- track reference position plus offset lngref = +00:02:00.0 !- reference position is 30 arcmin east of source latref = 00:00:00.0 !- obstype = TRACK !- observation type corrmode = NORMAL !- spectral mode obsval = 12 !- observe the reference position for... obsunit = cycles !- 12 cycles drive !- go to the reference position go !- $ unit 2 !- central position srcoff = NONE !- track source without any offset lngsig = 00:00:00.0 !- latsig = 00:00.00.0 !- go !- $ unit 3 !- SOUTH srcoff = SIGNAL !- track source position plus offset lngsig = 00:00:00.0 !- latsig = -00:00:30.0 !- position is 30 arcsec south of source go !- $ unit 4 !- EAST srcoff = SIGNAL !- track source position plus offset lngsig = +00:00:02.0 !- position is 30 arcsec east of source latsig = 00:00:00.0 !- go !- $ unit 5 !- NORTH srcoff = SIGNAL !- track source position plus offset lngsig = 00:00:00.0 !- latsig = +00:00:30.0 !- position is 30 arcsec north of source go !- $ unit 6 !- WEST srcoff = SIGNAL !- track source position plus offset lngsig = -00:00:02.0 !- position is 30 arcsec west of source latsig = 00:00:00.0 !- go !- $ unit 7 srcoff = REFERENCE !- track source position plus reference offset lngref = +00:02:00.0 !- reference is 30 arcmin east of source position latref = 00:00:00.0 !- go !-
In this example, we want to observe a galaxy (point source) with seven (7) beams of the Multibeam receiver. The source is observed within each beam in turn. For each of the 7 beams, the source is observed for 32 cycles (=32x5 seconds).
$ unit 1 !- Define new scan observer = Walt !- Identify observer(s) project = P999 !- Identify project ID doppl1 = T !- Doppler correction ON frame = topocentric !- Velocity frame conv1 = optical !- Velocity convention config = mb7_8_2048 !- Correlator config fcc_p_t = disable !- No parallactification source = NGC205 !- Source name fitsname = P999_NGC205 !- Output RPFITS name with project ID included vel1 = 3543 !- Velocity of source raj = 04 23 43 !- RA (J2000) of object decj = +02 23 23 !- DEC (J2000) of object fcc_rot = 0 !- Receiver rotation (deg) cycles = 32 !- Number of 5 sec cycles obstype = mx !- Observing mode go !- Start the observation closef !- Close RPFITS file after observation finishes
Bugs and anomalies:
TCS is inappropriately writing the coordinate mode into the 'EPOCH' header of the RPFITS file output. For example, a file written in AZEL mode will contain EPOCH = 'AZEL ...' in its header. This is not really consistent: the true epoch is always J2000. (Although the 'EPOCH' header card is obsolete, non-numeric values cause e.g. ATLOD to crash).
Status: Pending
Selecting correlator mode PSR (pulsar binning mode) erroneously forces fast-sampling mode for the Multibeam samplers, preventing any spectra from being formed and any RPFITS file from being opened.
Status: Fixed at 1.21.
The widgets "start" and "end" specifying the start and end scans for a schedule can "freeze" if they are accessed while a long schedule (e.g. a standard HIPASS schedule) is still loading. This is apparently a Glish "feature". The fix is to take the cursor outside the TCS GUI to any blank part of the screen and click the left mouse button. The widgets should then be OK. Avoid accessing these widgets until the log shows that the schedule has loaded.
Status: Glish "feature"
If the loboss server is not running, any attempt to start a scan/track etc. fails with errors;
07:21:38 configok received 07:21:38 (E) <ERR> send failed in lo_ctrl 07:21:40 Stop cmd
Status: Pending