1 AUTO OBS\AUTO Time TWEAK|NOTWEAK Starts a simple auto-correlation measurement, optionally preceded by a tweak (sampling level adjustment) of the spectral correlator. Time defines the integration time in seconds. The continuum correlator output is used to derive further Van Vleck corrections. 1 BANDPASS OBS\BANDPASS [Time] Start a specific procedure to calibrate instrumental phases of the spectral correlator. Default integration time is 5 seconds. The spectral correlator is automatically connected to a noise source for this purpose. Delay and phase tracking are cancelled during the measurement. 1 CALIBRATE OBS\CALIBRATE [COLD] Starts an atmospheric amplitude calibration. The calibration is done by measurements on the absorber, on the sky, and optionally on the internal cold load when argument COLD is given, by moving the receiver tables and mirrors. An extra attenuation can be inserted in the receiver 1 when measuring the power on the absorber; this attenuation is specified by command OBS\SET ATTENUATION. The calibration mode can be specified by the OBS\SET CALIBRATION command. In INTERferometric mode, the Correlators and the total power Detectors are used. The spectral correlator is always tweaked in this procedure. This command is not available in OPTICAL or TEST modes. 1 CANCEL OBS\CANCEL [CANCEL|KILL|STOP] The command CANCEL interrupts the data acquisition process. OBS\CANCEL Cancels current scan loop. Data acquisition is stopped at end of the next subscan. A CANCEL is implicitely done by C in multi subscans procedures, such as FOCUS, POINTING and SKYDIP. OBS\CANCEL KILL Aborts current scan. Data acquisition is stopped as soon as possible (depending on observing procedure) and the data are flagged "Deleted" in the output file. CANCEL KILL may be used after C has been pressed during a multi subscans command (FOCUS, POINTING, or SKYDIP). A CANCEL KILL is implicitely done by a command MICRO. OBS\CANCEL STOP Requests reduction programs (RDI and AFF) to stop. OBS\CANCEL WAIT Allows OBS to proceed when it would normally say ``Waiting for ...'' This command has to be used only when something abnormal happened in the acquisition (e.g. RDI crash). 1 CATALOG OBS\CATALOG [SOURCE|LINE|PHASE] Name Select a new catalog for sources, line frequencies, or phase calibrators. Default catalogs are Sources INTER_BASE:IRAM.SOU Line INTER_BASE:IRAM.LIN Phase INTER_BASE:PHASE.SOU 1 CORRECTIONS OBS\CORRECTIONS Caz Cel [Focus] [/ANTENNA Iant] Enters pointing corrections and the focus zero for antenna Iant. Caz and Cel are offsets from respectively -COH and -COV, the radio collimations, while Focus is an offset from HFO0 the nomi focus. Using * instead of a numerical value means do not change this parameter. Caz and Cel are in arcseconds, while Focus is in millimeters. In single-dish mode, Iant defaults to the single-dish antenna Command CORRECTIONS is intended to be used for temporary changes only, for example to help in a pointing session, or to refine the current pointing on a particular source. Corrections are remembered by OBS using the MEMORY.OBS procedure, and NOT reset to 0 by a SET\OBSERVE or SET\POINTING command. To change permanent pointing parameters, the SET\POINTING command is recommended, and corrections should normally be set to zero. 1 DELAY OBS\DELAY Dmin Dmax Dstep/ANTENNA Iant Starts a delay-scanning measurement on antenna Iant. Dmin and Dmax are the minimum and maximum delays in nanosec. Dstep is the scan rate in nanosec/sec. The scanning is centered around the current delay offset. 1 DRIFT OBS\DRIFT [Length Speed Angle [Integration]] [/HORIZON] [/BASIS] Define a continuum drift single-dish procedure. - Length is the length of the drift in current angle units. - Speed is the drift speed ins arcseconds per second of time. - Angle is the orientation angle of the drift in degrees, and the option /HORIZON or /BASIS indicates whether this angle is in the Horizontal coordinate system or in the current Basis coordinate system. Standard orientation angles are +AZ -90 degrees -AZ +90 degrees +EL 0 degrees -EL 180 degrees - Integration is the integration time for each dump of the continuum detectors in seconds. 1 FLUX OBS\FLUX Start a cross-correlation (with default integration time) and use default antenna efficiencies to determine the source flux density. Subsequent correlations on the same source will compare the measure flux density with this value, and issue a warning in case of excessive losses. This command should be used once on each phase calibrator at start of a given project for proper monitoring. 1 FOCUS OBS\FOCUS [Length [Npos]] [/ANTENNA A1 ... An] In INTERferometric mode, starts an interferometric focus measurement. A1 ... An is the list of antennas to focus (default: all antennas). Three or more antennas must be connected, or one must be fixed. Npos is the number of focus position to check (3 or 5, default 3). Length is the focus displacement in millimeter (default 2.0 at 86 GHz). The command is forbidden in OPTICAL or TEST modes. 1 GAIN OBS\GAIN Starts a receiver gain-ratio measurement. At least three antennas are required for this procedure. This procedure is available only in INTERferometric mode. This is just a standard correlation, but identified specially to help data reduction. The current number of subscans is used. 1 HOLOGRAPHY OBS\HOLOGRAPHY dAz dEl Length Speed Direction /ANTENNA [A1 ... An] Start an holography measurement for antennas A1 .. An. Normally, only one antenna should be specified, but the command can also be used to initiate a drift to measure e.g. an azimut encoder. This command makes a drift in interferometric mode, centered around the specified dAz and dEl horizontal offsets. Direction can be +AZ, -AZ, +EL or -EL. Length and Speed are in " and "/sec respectively. For example the following procedure could be used to make a complete 32x32 beam map : DEFINE INTEGER BEAM LET BEAM 56 SET ANGLE SEC SET SUB 4 OFFSET 0 0/HORIZON CALIBRATE START FOR I -16 TO 15 BY 1 IF (MOD(I,2).EQ.0) THEN HOLOGRAPHY BEAM|2 I*BEAM|2 16*BEAM BEAM|8 +AZ/AN 1 ELSE HOLOGRAPHY BEAM|2 (I+1)*BEAM|2 16*BEAM BEAM|8 -AZ/AN 1 ENDIF OFFSET 0 0/HORIZON CALIBRATE START NEXT 1 LEVELS LEVELS [Goal] [/READ] Adjust the receiver attenuators to optimize the total power and correlator levels. Goal is the desired total power level, and should be between 100 and 200 (default 170, giving best efficiency). The adjustment should be made around the lowest elevation used for the observation. If option /READ is present, do not adjust the attenuator, but read their values from the microprocessors. 1 LINE LINE Name [Frequency Band [Lock [Center [Harm]]]] [/RECEIVER Irec] Specifies the observing frequency in MHz for all antennas. If no Frequency is given, the line is selected from the line catalog. The catalog format is the same as the LINE command format. Frequency is the observing rest frequency in GHz. Band is USB or LSB Lock is HIGH or LOW. Center is the IF frequency (in MHz) corresponding to the specified rest frequency. Default is 350 MHz. Harm is the harmonic number used to generate the LO1 from the LO2. By default, Harm is computed in order to give LO2 as close as possible to 1.875 GHz. The command is accepted in all modes, but sent (by command LOAD) only if the observing mode is INTERferometric. The relationship between the various frequencies is defined in the ``Frequency Setup'' document, and summarized below. (the signs defined according to the Band and Lock) 3mm receiver FLO2 = (FSKY +|- CENTER +|- EPS) / (HARM +|- 1) USB|LSB HIGH|LOW USB|LSB 1.3mm receiver FLO2 = (FSKY +|- CENTER +|- 3*EPS) / (3*HARM +|- 1) USB|LSB HIGH|LOW USB|LSB where FSKY = FREST*(1-v/c) is the Doppler corrected frequency EPS = 100 + 50/512 1 LOAD OBS\LOAD [/AZIMUTH Dir] [/FREQUENCY] Loads observing parameters. This command sends source position, frequency information, and a number of other things to the telescope control program, but data acquisition is not started. A LOAD is implicitly done by all acquisition commands. The Option /AZIMUTH can be used to force antenna to chose a slew direction; Dir can be +AZ or -AZ. A LOAD command is necessary before receiver tuning. The Option /FREQUENCY will only send the frequency with Doppler corection for the new source, but without antenna movement. 1 MICRO OBS\MICRO Aborts the current acquisition and put all antennas under Micro control. To be used in case of emergency such as antenna oscillations. 1 OFFSETS OBS\OFFSET Off\ Off\Beta [Off\Focus] [/HORIZON] [/BASIS] Defines source or focus offsets for ALL antennas. Position offsets are in the current angle units. In the BASIS coordinate system, they define the antenna and delay tracking center; in the HORIZONTAL coordinate system, only the antenna tracking center is modified. Focus offsets are in millimeters. OBS\OFFSET Off\ Off\Beta [/DELAY] Defines only the delay tracking offsets (a useful feature to avoid artificial sources at the source position caused by correlator errors). 1 ONOFF OBS\ONOFF Off1 Off2 [System] [/TIME Tsub] [/SUBSCANS Nsub] Start a on-off multi-dish procedure. Tsub is the integration time on each position (subscan duration). Off1 and Off2 are the angular offsets (in current angle units) for the reference position, and System is the coordinate system in which they are defined (Horizon or Basis, default as specified in SET OFFSET). Nsub is the number of subscans pair; default value is the number of subscans defined for single-dish measurements. Auto correlation are made without tweaking. Data is written in the the compressed file INTER\COMP:Date.IPB) using the following CLIC procedure : CLIC\SET X IF CLIC\SET ANTENNA 1 2 3 4 ! As available CLIC\SET Y AUTO CLIC\FIND/PROC ONOF CLIC\PLOT 1 POINTING OBS\POINTING [PSEUDO] [/ANTENNA A1 ... An] [/FAST] [/LENGTH Length] [/AZIMUT +-Az] [/ELEVATION +-El] In INTERferometric mode, starts an interferometric pointing measurement using the correlators in cross-correlation mode. Three or more antennas must be connected, or one must be fixed. A1 ... An is the list of antennas to move (default: all antennas moved). If argument PSEUDO is specified, the pointing is done in ``pseudo- continuum'' mode, i.e. in auto correlation. One subband of the correlator should have been selected to match a strong spectral line in this case. Four drifts are made (Az increment, Az decrement, El increment, El decrement). The command is forbidden in OPTICAL and TEST modes. Option /FAST can be used to scan twice faster than usual. Option /LENGTH can be given to modify the scanning length: the argument is actually half the scanning length in arcseconds. Options /AZIMUT and /ELEVATION can be used to select which drifts are actually performed among the 4 possible: +Az, -Az, +El, -El. 1 SAVE OBS\SAVE The SAVE command creates a new version of the INTER\BASE:MEMORY.OBS file, which contains current values for antenna variables parameters (efficiencies, calibration parameters, current source, etc...). This file is automatically executed each time OBS is activated, and updated each time OBS terminates. 1 SET OBS\SET Parameter Value [/ANTENNA Iant] Specifies some observing parameter. 2 ANGLE SET ANGLE Degree|Minute|Second|Radian Define the current angle unit 2 ARRAY SET ARRAY A1 A2 A3 Specifies the antennas currently available in the interferometer. SET ARRAY also indicates which antenna should be used for the MULTI-DISH mode. This command is intended for temporary unavailability of antennas still on station. The CONFIGURE mode command SET\ANTENNA should be used otherwise. 2 AMBIENT SET AMBIENT T_amb P_amb or SET AMBIENT Auto Defines the external temperature and pressure, or specifies use of the meteo station. 2 ATMOSPHERE SET ATMOSPHERE T_atm_s T_atm_i /ANTENNA Iant Defines the atmospheric temperatures in signal and image bands. This is required in the CAL MANUAL mode only. 2 BEAM_THROW SET BEAM_THROW Bs /ANTENNA Iant Indicate the beam separations Bs (in arcsecond) for beam-switch observations. This is a hardware value, not a software controlled parameter. 2 CALIBATION SET CALIBRATION AUTO|MANUAL|NONE|TREC /ANTENNA Iant Defines the calibration mode NONE: uncalibrated spectra & data MANUAL: Manual guess of atmospheric transmission AUTO: fix Water, compute Trec TREC: fix Trec, compute Water 2 CHOPPER SET CHOPPER T_warm /ANTENNA Iant Defines the absorber chopper temperature for antenna Iant 2 DEBUG SET DEBUG On|Off On|Off On|Off For authorized users only. 2 FORWARD SET FORWARD F_eff /ANTENNA Iant Specifies the forward efficiency of antenna Iant. Beam efficiency is assumed equal to forward efficiency in all cases (antenna temperature scale). 2 GAIN_IMAGE SET GAIN_IMAGE G /ANTENNA Iant Specifies the image to signal gain ratio for antenna Iant 2 HUMIDITY SET HUMIDITY Humidity Specifies the humidity (for refraction correction) if the meteo station is not used. 2 INTEGRATION SET INTEGRATION Time Specifies the integration times between dumps for the cross- correlation 2 LEVEL SET LEVEL terminal file Specifies the level of printout (0 many messages, 2 Normal, 4 extremely limited) for terminal and log file (INTER_LOG:Date.LOG-OBS). 2 MODE SET MODE Imode [/ANTENNA Iant] Specifies the observing mode Imode, which can take the values INTERferometer: Select interferometric observing mode, allowing AUTO, CALIBRATE, GAIN, FOCUS, POINTING, SKYDIP and Cross correlation observing procedures. The correlators are used for pointing and focusing in cross correlation mode. In addition an ONOFF procedure allows spectra to be taken with all antennas at the same time. OPTICAL: This mode is used for optical pointing. The only allowed commands are SOURCE and LOAD in this mode. The optical pointing constants and refraction model are used for tracking. CONFIGURE: This mode is used to specify a change of hardware configuration, such as new position of antennas, new IF connections, new pointing constants, etc... The OBS\ language becomes inactive, and the SET\ language is turned on. Observations can be resumed only using the SET\OBSERVE command. TEST: This mode is used for tests of the correlators. LO1 Walsh switching, phase and delay tracking are suppressed. The spectral correlator is automatically connected to the noise source. The continuum correlator must be manually connected to another noise source to be tested. Antennas are unused and several commands become unavailable in this mode. 2 OFFSETS SET OFFSETS Basis|Horizon Specifies the coordinate system to be used for offsets. 2 OPACITY SET OPACITY Tau_S Tau_I /ANTENNA Iant Specifies the atmospheric opacities in signal and image band for antenna Iant. Required only in CAL MANUAL mode. 2 SHOW SET SHOW ON|OFF Selects or disables the "full-display". 2 SCAN SET SCAN Ns Specifies the number of scans requested by each START command. 2 SUBSCAN SET SUBSCAN Ns Specifies the number of subscans for each scan. 2 TABLE SET TABLE Sky Specifies the table position for observation on Sky, as a percentage of total displacement (0 : sky only, 100 absorber only). This value is common for all antennas. 2 TREC SET TREC Trec /ANTENNA Iant Specifies the receiver temperature for antenna Iant. Required only in CAL TREC mode. 2 WATER SET WATER wH2O Specifies the water vapor content of the atmosphere (in millimeter). Required only in CAL AUTO mode. 1 SHOW OBS\SHOW [* | Item] OBS\SHOW : Refreshes the "full-screen" display OBS\SHOW * : Lists all parameter values. OBS\SHOW item : List one parameter. The available parameters are ANGLE D|M|S : Angle unit type AMBIANT Tamb Pamb | AUTO : Meteo parameters and mode ARRAY List : Antennas in array ATMOSPHERE T_atm_s T_atm_i : Atmospheric temperature (*) ATTENUATION Att_1 Att_2 : Attenuation for calibration BEAM_THROW Value : Chopper throw (*) CALIBRATION AUTO|MANUAL|NONE|TREC : Calibration mode (*) CHOPPER T_warm T_cold : Chopper temperatures (*) CORRECTIONS -COH -COV HFO0 : Pointing and focus corrections (*) DEBUG On | Off : Debug flags (for test only) FORWARD F_eff : Forward (=Beam) efficiencies (*) FIT On | Off : Fit pointing scans ? GAIN_IMAGE G : Gain/Signal band ratio (*) LEVEL terminal file : message priority level MODE : OBS operating mode OFFSETS Basis | Horizon : Offsets type OPACITY Tau_S Tau_I : Atmospheric opacities (*) PHASE Atm | Noatm | Both : Atmospheric phase compensation SCAN Ns : Number of scans per START SUBSCAN Ns : Number of subscan per scan TABLE Sky : Table OFF position TREC Trec Tsys : Receiver and System temperature (*) WATER wH2O : Water vapor content (*) Parameters marked (*) may depend on antenna. All antennas are listed in this case. 1 SKYDIP OBS\SKYDIP Azi [/ANTENNA A1 ... An] Starts a skydip measurement with the specified or all connected antennas at azimuth Azi. The continuum detectors are used. A measurement on the tables is made first then the sky emission is measured at 6 different elevations equally spaced in air masses, starting from 45 degrees elevation. The data is written in the .IPB file, and no real time reduction is available. The command is forbidden in OPTICAL and TEST modes. 1 SOURCE OBS\SOURCE Name [Coordinates ...] /TYPE OBJECT|PHASE|BAND [/VELOCITY Vtype [Vvalue]] [/FLUX Fvalue] Selects a source of the specified type: OBJECT for sources to study, PHASE for Phase calibrator, BAND for Bandpass calibrator. The SOURCE catalog is searched for OBJECT type sources, while the PHASE catalog is searched for PHASE and BAND sources. Source coordinates may be in the command line, in the same format as the source catalog, i.e. NAME Syst [Epoch] Lambda Beta Vtype [Velo] [FLUX Value] W3OH EQ 1950.0 02:23:16.50 61:38:57.0 LSR -45.0 FLUX 3.73 Where Syst is the coordinate system (EQ, HO, GA) and Epoch its optional epoch. Lambda and Beta are the coordinates (in hours and degrees for EQ coordinates, in degrees only for HO and GA coordinates). Vtype is the reference frame (LSR, EARTH, HELIO, or NULL which means no Doppler tracking) and Velo the velocity in km/s. FLUX is a keyword indicating a value for the continuum flux (in Jy) at 3mm. The /TYPE option is compulsory, and indicates in wich catalog the source should be searched. PHASE and BAND sources have a velocity type NULL to avoid changing the observing frequency between the source and the calibrator. The /VELOCITY Vtype Vvalue and /FLUX Fvalue options can be used to override the velocity or flux specified in the catalog. 1 SPECTRAL OBS\SPECTRAL Unit Bandpass IF_2 [/CONTINUUM Band_C LO2_C] [/RECEIVER Irec] Configures the spectral correlator unit number Unit. Bandpass indicates the contiguous bandpass to be used (20, 40, 80 or 160 MHz). IF_2 is the second IF frequency of the bandpass center. It is rounded to the nearest multiple of 0.625 MHz (the LO3 frequency step). The /CONTINUUM option specified which bandpass should be analyzed to produce the temporal data. The default is 80 % of the original band. Option /RECEIVER is used to indicate to which receiver the unit should be connected. 1 STABILITY OBS\STABILITY Time [TWEAK|NOTWEAK] Perform an autocorrelation of specified integration time on the calibration table ("Hot" load), and analyse the result in terms of receiver stability. Time should be at least 60 sec. 1 START OBS\START In INTERferometric or TEST mode, starts a cross-correlation measurement, using the number of scans and subscans specified by the SET SCANS and SET SUBSCANS commands and integration time specified in SET INTEGRATION. 1 END