So here are the steps for a standard astrometry reduction.
- get_data,'2001-03-16.coh' (Read a CONSTRICTOR file with coherent integrations.)
- hds_close
- REDUCEBG DATADEFAULT BG
(To make sure every scan has a back ground rate
and set it to zero since we don't care about the
visibility calibration.)
- REDUCEPOINT DATAASTROMETRYPHASEEDIT
(Flag all channels higher than 20
as well as the laser channel 11. Data after about May 2002
only need channel 12 of spectrometer 1 flagged. This is done
automatically.)
- flagphase,2,1,chan=indgen(16)+1 Optional flagging of baseline
1 in beam 2, in this example. This is needed if the same baseline
occurs twice in the data. In the case of a reference baseline,
the one in the first beam would be overwritten by the one in
the second beam, and so on, in the dispersion correction procedure.
- REDUCEPOINT DATAASTROMETRYPHASEWRAP
(Unwrap the phases as a function
of channel.)
- REDUCEPOINT DATAASTROMETRYDISPCORR
(Compute dispersion correction.)
- REDUCEPOINT DATAASTROMETRYPLOT (Plot VACDELAY,
i.e. the dispersion corrected delay relative to the predicted
geometric delay and
flag. Use PLOTAUTO. The reference station values are zero
by definition.)
- hds_open,'2001-03-16.inch' (Open INCHWORM file.)
- get_metroconfig
- get_motiongroup,1
- hds_close
- pivotfit. An optional step which fits siderostat pivot
coordinates. RMS residuals should be on the order
of a couple of microns. After this step, plotting ParXYZ corr. will display the residuals (see next step).
- REDUCEINCH DATAPLOT. Plot azimuth versus elevation, connecting
data points with lines. Smooth curves should be the result. This is a
test whether proper siderostat models are loaded. Also plot ParX,Y,Z
to look for outliers.
- REDUCEINCH DATAINIT (For now, we plan on computing and
applying the metrology
correction after averaging, so we have to initialize the metrology
correction to zero for the calibrated delays not to be flagged during
averaging.)
- average
- inchav
- CALIBRATEASTROMETRYMETROCORR (Compute and apply constant term
and pivot corrections.)
- CALIBRATEASTROMETRYSOLVE (Compute astrometric solutions)
