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OBSTYPE tells SCHED what type of observation this project is. There are really only four options, although there are several ways to specify most of them. They are:

Mark II.
Specifying either OBSTYPE = MKII or MARKII causes SCHED to assume that the Mark II recording system will be used. This system is now obsolete, although maybe not totally gone, so this should not be common. It causes tape change requests to occur at time intervals specified by AUTOTAPE and assumes the Mark II tape is to be left running.

Wide band recordings.
Specifying VLBI, VLBA, MKIII or MKIV causes SCHED to assume that the wide band recorders (tape or disk) are in use. For the wide band recording modes, the necessary information on tape speed, passes per index position, etc., is taken from the setup file and the TAPEFILE and the type of recorder to use is based on the station catalog and the TAPEFILE parameter MEDIA. If there is a gap between the stop time of one scan and the start time of tape motion in the next (after taking into account START, DWELL, GAP, and PRESCAN), then SCHED will insert a dummy scan with no tape motion (or possibly a rewind or fast-forward) during this gap. Note that there is no requirement that the FORMAT in the setup file match which OBSTYP is specified. In fact, it is allowed to mix types at different stations. For historical reasons, VLBA, MKIII, MKIV, MARKIII and MARKIV are allowed alternatives with the same effect as VLBI and some of these appear in the examples.

SCHED does not support Mark III recordings on other than VLBA systems -- the snap output contains no tape commands. In any case, Mark III is obsolete and no longer in use.

Pure VLA observations.
If OBSTYPE = VLA, SCHED will assume that only the VLA is being scheduled and that VLBI recorder setup or commands are required. This is the mode in which SCHED can be used for many types of VLA scheduling. With the advent of the EVLA project, SCHED should no longer be used for scheduling pure VLA projects so this option is basically obsolete.

Single dish observing.
OBSTYPE = NONE or PTVLBA (the default) causes recorder handling to be ignored. This is mainly for VLBA single dish pointing observations. This does set up the channels in the Data Aquisition System (BBCs, IF distributers etc), but does not record VLBI data.

Configuration studies.
OBSTYPE = CONFIG causes a map of station locations to be plotted when plotting uv coverage for multiple sources. This is mainly for array design configuration studies. The axis limits are set with parameter MAPLIM and default to values appropriate for NMA configuration studies. Continental, national, US state, and New Mexico roads will also be plotted if the vector files are available in $PLANET_DATA as they are in Socorro. If you want to use this capability, you might wish to contact Craig Walker about details and help -- it is not really meant for general use.

next up previous contents
Next: OPDUR Up: Details of SCHED Parameters Previous: OBSPHONE   Contents
Craig Walker 2014-06-17