Observing with CABB at ATCA

1. setup the array
   • set the CABB attenuators
   • calibrate delays, phase and amplitude
2. do a bandpass and flux calibration
3. do your science

If you are doing mm observations, step (1) above also needs to include mm attenuaters. Here is a "recipe" for CABB observations.
(NOTE: these notes assume that the CABB correlator is already configured for your obs.)

-- 3mm -- 7mm --

3mm CABB cheatsheet

1. change over
   • set your file and track a strong source:

     CAOBS> stop
     CAOBS> corr closefile
     CAOBS> set file filename
     CAOBS> stow ca06
     CAOBS> detach ca06
     CAOBS> track #

   • 3mm setup:

     CAOBS> set point_a 12345
     CAOBS> set point_p 2
     CAOBS> set point_ifflag 1234
     CAOBS> focus ca01 14

2. set the attenuators:
   • check the CABB attens (in the CACOR "samplers" tab - levels should be 20+/-1). If the CABB attens are out of range you need to set them:

     CAOBS> corr atts on

     This might fix them, so wait a few cycles to check. If not, fiddle with the mm attens:

     CAOBS> set mm ca0# 0 0

     and repeat for all antennae as needed. 0 0 are the standard levels for 93GHz/95GHz. You may need to change these numbers to get the sampler levels ~20 in both polarisations and in both frequencies on all attennas. Once set,

     CAOBS> corr atts off

3. calibrate the array:
   • while still tracking the strong source, set the delays (i.e. bring all delays back to zero, and this will also flatten the phases in SDP):

     CAOBS> corr dcal a

   • then do a pointing:

     CAOBS> stop
     CAOBS> start # (where # is your pointing scan)

   • then set the amplitudes with a paddle:

     CAOBS> stop
     CAOBS> start # (where # is your paddle scan)

   • and finally set the phases (i.e. bring them back to zero also):

     CAOBS> corr pcal a
     CAOBS> stop
     CAOBS> corr closefile

4. bandpass calibrator, flux calibrator, and science!

7mm CABB cheatsheet

1. Do NOT detach ca06 !!! Antenna 6 has a 7mm receiver, so keep it in! (And check that it is already attached.)

2. set your file and track a strong source:

   CAOBS> stop
   CAOBS> corr closefile
   CAOBS> set file filename
   CAOBS> track #

3. 7mm setup:

   CAOBS> set point_a 123456
   CAOBS> set point_p 2
   CAOBS> set point_ifflag 1234
   CAOBS> focus ca01 17

4. set the attenuators:
   • check the CABB attens (in the CACOR "samplers" tab - levels should be 20+/-1). If the CABB attens are out of range you need to set them:

     CAOBS> corr atts on

     This might fix them, so wait a few cycles to check. If not, fiddle with the mm attens:

     CAOBS> set mm ca0# 0 0

     and repeat for all antennae as needed. If the numbers are low and the attenuation is also on 0, then there's nothin you can do... Once set,

     CAOBS> corr atts off

5. calibrate the array:
   • while still tracking the strong source, set the delays (i.e. bring all delays back to zero, and this will also flatten the phases in SDP):

     CAOBS> corr dcal a

   • then do a pointing:

     CAOBS> stop
     CAOBS> start # (where # is your pointing scan)

   • then set the amplitudes:

     CAOBS> stop
     CAOBS> track #
     CAOBS> corr acal #1 #2 a (where #1 and #2 are the amps of that calibrators at F1 and F2)

   • and finally set the phases (i.e. bring them back to zero also):

     CAOBS> corr pcal a
     CAOBS> stop
     CAOBS> corr closefile

6. bandpass calibrator, flux calibrator, and science!

Last updated: July 2012

smaddison_at_swin.edu.au
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