Setting up reference pointing in ATCASCHED

The pointing calibrator may be a continuum source or a strong maser. Continuum sources stronger than 2 Jy (average flux density over the bandpass) are preferred. See www.narrabri.atnf.csiro.au/calibrators to help select a continuum source. For SiO masers, see the SEST `List of Pointing Sources' at www.atnf.csiro.au/observers/docs/3mm/obs/sio-sources.html

At higher frequencies, calibrators are quite variable, so it can be useful to have several backup sources to try if the chosen calibrator is not as strong as advertised.

Creating the schedule file for calibrator and target source:

	Use ATCASCHED to set:
	$>$ sctype point

To instruct CATAG to determine the pointing offsets, and load a new pointing solution into the ACCs:

	$>$ pointing update		Start with the current offsets.
	This is generally best at 3mm
	$>$ pointing refpnt		Start with the global solution.
	This is often a good idea at lower frequencies
	Set the scan length to 5 minutes.
	$>$ scan 5m		ATCASCHED will probably warn about scans not being long enough; ignore it (unless you expect a particularly long drive time). CAOBS will move to the next source in the ATCASCHED file as soon as the pointing is complete.
	For all pointing calibration scans:
	$>$ averaging 1		Ie. No averaging. Do not average data over the variety of offset pointing positions in a point pattern.

Use wide bandpass modes only, eg. 128 MHz. Set the correlator configuration accordingly.

To apply the new pointing solution to a target source:

	Schedule the target source scan with:
	$>$ sctype dwell		Or SCTYPE unset.
	$>$ pointing offset

If required, please see the additional information.