Australia Telescope National Facility

Writing Schedules

A schedule is the text document that describes the observing parameters for an observation (e.g. position, frequency, bandwidths, time on source etc.)

A schedule will contain the information for a number of scans. Each scan is the information for an individual pointing.

Currently (August, 2006) this is generally done on the VMS computer, leon.

Simple Schedules

For a simple, cm observing program, with one source and a matching calibrator scans: two schedules need to be created,

1. a calibration schedule with the primary calibrator (pks1934-638) scan and a set up scan (e.g. pks0823-500 or pks0407-658) if pks1934-638 is not up at the start of your observations.
2. the observation schedule needs to contain information on your source and a calibrator that you choose to match your source. For information on calibrators see ATCA Calibrator Manual

To create a schedule:

1. telnet into leon as sched (no password needed)
2. fill in schedule fields by using the first few letters (min-match applies) as the prompt for the field you wish to change e.g.
   > con full_128_2
   would set the 'config file' field to full_128_2
3. when a 'scan' is defined, the add command adds this scan to the schedule
4. the list command gives summary information about the contents of the schedule
5. when the schedule is completed, the write command actually writes the schedule to the file that caobs has accesses.

Most fields need to be filled in: Including project_id, observer, source, RA, Dec, epoch, scan length, 1frequency, 2frequency, config file. The config file needs to be one known to the correlator: When the config file is set, 1bandwidth and 2bandwidth will be modified to match.

If choosing a source from a catalog, you can use the command
> cat source_name catalog_name
(e.g. >cat 1934-638 calibrators)
and the schedule software will look up name, RA, dec, epoch.

12mm Schedules

For most 12mm observing, the antenna pointing needs to be checked and corrected around once an hour. To do this, a reasonably strong (> ~1Jy), reasonably close (<~15° away) source needs to be choosen as pointing calibrator. (The secondary calibrator is usually appropriate for this.)
For the pointing scan:
set pointing to 'update' and
scty to 'point'.
For all other scans:
set pointing to 'offset' and
leave scty as for normal observing (e.g. 'dwell' etc.)

If the scan times are short several calibrator/source scan pairs need to be loaded into the schedule, so that time isn't wasted with more than one pointing scan an hour.

3mm Schedules

Even the simplest 3mm schedules are more complicated as you need to include paddle and pointing scans, and the scan length on source needs to be shorter. As a guide, most 3mm observations would have a schedule something like:

• pointing scan (~4 mins)
• paddle scan (~1 min)
• calibrator scan (~2 mins)
• source scan (~10 mins)
• calibrator scan (~2 mins)
• source scan (~10 mins)
• calibrator scan (~2 mins)
• source scan (~10 mins)
• paddle scan (~1 min)
• calibrator scan (~2 mins)
• source scan (~10 mins)
• calibrator scan (~2 mins)
• source scan (~10 mins)
• calibrator scan (~2 mins)
• source scan (~10 mins)

For more information, see the ATUC User's Guide

<< Introduction

Starting Observations >>