1 Description
-------------------------------------------------------------------------------
Standard Calibration package                              R. Lucas 05-feb-1997 
-------------------------------------------------------------------------------
This is the X-window form of the standard calibration procedure
@pr:calib2, to calibrate Plateau de Bure data. It calibrates both
receivers in parallel. The phase curve from receiver 1 is used to help
calibrate receiver2. The procedure works also for 1 receiver only.
 

Active Buttons:
---------------
GO	Perform all calibration steps in sequence.

SELECT  Select observations; Must be done after FILE is changed.
	The RF bandpass calibration source is selected as the strongest
	source of type PHASE with correlation observations, inside
	the scan_range parameters. For each receiver, the useful band 
	(LSB, USB, or DSB) is selected according to the sideband gain 
	ratio. Note all scans with quality worse  than MIN_QUAL are
	ignored. Use STORE QUALITY to change the quality on scans.
	SELECT will recover the results from previous calibration sessions
	on the same file (possibly interrupted for any reason).

PHCOR   Calibrate Atmospheric Phase correction. This runs command MONITOR
	with no arguments, then STORE CORRECTION AUTO.

RF	RF Passband calibration on Rec. 1, then 2, with the USB and/or LSB.
	 
JUMPS   Select possible phase jumps due to FOCUS corrections. The 
	corresponding option (/BREAK 0 t1 0 t2 ...) is stored in symbol 
	'BREAKS'. This option may be  used for the phase calibration
	of receiver 1 (not necessary for data more recent that nov 96), 
	or for amplitude calibration.

PHASE   Phase calibration of receiver 1 is computed, then stored 
	applied in  data of both receivers. Then the phase calibration
	of receiver 2 is computed, on top the receiver 1 phases
	(SET PHASE EXTERNAL). 

EFF	Efficiency  measurement. The flux of the bandpass calibrator at each
	frequency is read from the file.
	It is used as a reference to compute the antenna efficiencies at
	each frequency, as well as the flux of the other calibrators. 
	The flux of the absolute
	calibrators (MWC349 and/or CRL618) is compared to the predicted values.
	No flux is stored in the data file. 
        The determination of the calibrators fluxes should be refined 
        by pressing FLUX for each receiver in turn.

AMPL	Amplitude calibration for receiver 1, then for receiver 2.

PRINT   Prepare report: file_name.sum (a summary ASCII file), file_name.tex
	and file_name.ps (Postscript file including plots). 
	The latter are only produced if parameter DO_TEX is true.

Inputs:
-------
2 DO_RECOVER
"Use previous settings ?"
	Use the settings of a previous calibration session on the same file,
	if any. If NO, the default settings will be restored; if YES, the 
	previous settings (including: scan range, minimum quality, ...) are
	restured when SELECT is pressed.

2 DO_EXTERNAL
"Use R1 phases for R2 ?"
	if YES: Phase calibration of receiver 1 is computed, then stored 
	applied in  data of both receivers. Then the phase calibration
	of receiver 2 is computed, on top the receiver 1 phases
	(SET PHASE EXTERNAL).
	if NO: Both receivers are processed independently.

2 DO_ATM
"Use Phase correction ?"   
	Use atmospheric phase correction. If YES PHCOR step must have 
	been done. SHould always be YES since PHCOR will determine if 
	phase correction is useful and turn it ON/OFF on a scan-based basis.

2 DO_SELF
"Self cal. phases R1->R2 ?"
	For calibrators, directly correct the 1mm phase by the 3mm phase,
	appropriately scaled by the ratio of frequencies.
  	Then the determination of the residual correction (e.g. the
	variation of the relative instrumental phase) is much easier since the
	atmospheric phases have been cancelled. The noise should be purely 
	statistical. This is the default.
	In that case the atmospheric quality (seeing) is determined 
 	from receiver 1 only.


2 IREC
"Receiver numbers ?" 
	e.g. "1 2" for both, "1 0" for 1 only, "2 0" for rec. 2 only; 
	if both, use rec. 1 phase for rec. 2

2 FILE_NAME
"File name ?"   
	Press FILE for browser.

2 SCAN_RANGE
"Scan range ?"
	First and Last scan to be used. Set FIRST = 0 and LAST = 10000 
	for all scans (the default).
	
2 MIN_QUAL
"Minimum quality ?"
	Minimum data quality required for data selection. 

1 END