Making and displaying beam maps

Beam maps being total power output maps, should be made with the a/d, independent of whether they are done with the bolometer or with a heterodyne receiver.

In case of the bolometer, start a new data file for each map, everything else is like for every other OTF map.

In case of a heterodyne receiver, tee-off the total power output at the chart recorder and plug it into the a/d's channel 1 (it is labelled). Make sure the OTF trigger signal (it originates from the antenna computer but is usually fed through from the sidecab) is connected to the external trigger input in the back of the a/d (NOT channel 2 of the bolometer - channel 2 of the bolometer is ONLY used for triggering for the FTS). In the UIP, switch to bolometer mode (BOLOMETER command), start a new data file after doing so (spectral line and continuum data don't mix well - nobody has succeeded in separating them back out yet for all that we know). Just like with the bolometer, start a new file for each map.

The map itself should be a simple OTF map.

To display these maps there is a version of the CONTOUR program that is able to take care of row spacing, independent of whether the rows are spaced in DEC or in ZA. It lives in USER:[MAREN.UTIL.CONTOUR] and is called CONT_ADDMAP (thanks to Thomas Buettgenbach). The input is a little bit cryptic in that the period that separates filename and filename-extension has to be input either with the filename or with the extension (but it has to be there!!), but other than that should be fairly self evident.


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Maren Purves,

July 2, 1996