Opened 14 years ago
Last modified 12 years ago
#200 new task
Routine for processing cross-scan data
| Reported by: | Owned by: | Malte Marquarding | |
|---|---|---|---|
| Priority: | normal | Milestone: | Unified development |
| Component: | General | Version: | 2.0 |
| Severity: | normal | Keywords: | |
| Cc: |
Description
As the DFBs at Parkes do not have a total-power mode, one cannot use 'SPOT' scans (as done with the Multibeam correlator) to obtain flux calibration factors. However we can do 'spider-scans' (see below) and it would be nice to have a function in ASAP which could process a series of 'spider-scans' to extract flux calibration factors and other information. For the Multibeam correlator, total-power SPOT observations produce the following for each polarization:
Beam FWHM
ampR (amplitude of RA scans)
ampD (amplitude of DEC scans)
ON-OFF (baseline)
The calibration factors for each pol are then obtained using the following formula:
N x ((ON-OFF x 2) / (ampR + ampD))
N is the flux of the source in Jy (i.e., obtained from MIRIAD's calplot utility).
AZ-EL "spider" scans (..., -90, -45, 0, 45, 90, ...) are referenced to an RA/DEC position. The scans are conducted along the Great Circle passing through the source.
There is now a utility called pyspot which addresses the above and is built on ASAP:
http://www.parkes.atnf.csiro.au/cgi-bin/public_wiki/wiki.pl?PySPOT
It also requires numpy and scipy.