Date: August 10, 2012 (Friday) Time: 15:00 to 16:00 EDT Location: Concord ave 160, 2nd Floor (M-240)
1) Questions and Answers on SMA data reduction in Miriad
Since April 25, 2012, the flagging status for iPointing data in the MIR format has been
changed (item 1 below):
http://www.cfa.harvard.edu/sma/miriad/download/OnLineIssues/kYoung25apr2012SMAdformat.html
In SMA beta 1.4.5, the default in SMALOD has been changed to excluding the non-zero position
offset iPointing data. To retain all the iPointing data, please use 'options=ipoint':
Task: smalod
Responsible: Jun-Hui Zhao
SMALOD is a MIRIAD task, which converts the standard SMA data
format to Miriad format. It also automatically selects SMA
doubleband patch for handling 4GHz data.
...
Keyword: options
...
'ipoint' An option to keep the ipointing data. The default is
to flag iPointing data with non-zero offset from source.
This option only applys to the data after 2012apr25.
...
2) Changes of SMA online/archive data format
Many interesting suggestions and ideas have been discussed lately for coping with the new broadband correlator data, including use of the CASA (previous name: AIPS++)'s data format.
There were several meetings at CfA to discuss SMA and ALMA in the past week.
No final decision has been made yet whether directly, or via a translator
if we adopt the ALMA/CASA format while the detailed specifications for the new MIR
format data structures have been postered for the interim correlator:
The current beta version of SMA Miriad has been stablized for the tested regular modes (4GHz/2GHz) data. The updated SMA components in the current beta version (1.4.5) will be integrated back to Miriad-CVS while we are preparing to support offline data reduction for the new broadband SMA correlator data.
The purpose to integrate the SMA components back to Miriad is to support more OS platforms in general use of SMA software for SMA data reduction and to archive the updated software versions in coping with the online changes and users' requirements. For the OS platforms, currently Redhat, Fedora and Ubuntu have been supported by the SMA developer with the Autoconf tool/procedure developed by UC Berkeley and the "old-style" installation config/procedures supported by U. of Maryland. The "old-style" installation procecure is used in general distribution of SMA beta Miriad. For the archive concerns, the backups of the distributed versions are archived in the CF system.
4) Miriad developer meeting for SMA
Peter Teuben from U. of Maryland will be in town for an ALMA meeting at CfA. He will spend an extra day with us. We will have a Miriad developer meeting at 9-11 am on Friday (8/10) in the same room (M-240). Mel Wright will call in from Berkeley. Miriad users are welcome to attend or call in. We will discuss the SMA beta merging back and the future plan to support SMA data reduction along with other efforts taken place in Miriad. Coordination with the Miriad development at ATNF will be discussed.
Since the 2009 Miriad-CVS (4.1.3), the base version for the current SMA beta, Miriad has made a significant breakthrough in handling a VERY LARGE size of data file using the newly invented tool for dynamic memory allocation in Fortran (by Bob Sault). Also, many updating and changes have been made to the 'uvio' and other uv routines since 2009. Major changes in the SMA Beta Miriad are the conversion software (SMALOD) for patching the software in handling the new observing modes for the doubleband (4GHz) correlator upgrade and coping with the internal data structure changes in the MIR data format. The changes in the SMA conversion routines are standalone (involving only the SMA specific routines) and will not require changes in the uv routines in the current Miriad-CVS. However, to support SMA engineer and users in debugging the hardware/online software and robustic use of Miriad in the reduction of SMA data, we were asked to add the super continuum (Ch0) data in the spectral window data identical to the way in MIR/IDL data handling and procedures to handle the IF/LO based data separately by stripping the specific IF windows using a simple paremeter in options instead of typing a long list of the window numbers in the SELECT function. For doing so, in the Miriad routines, we have added new uvflag parameters: c flags This is a character string determining the processing steps c that need to be performed. It consists of: c 'r' Get reference linetype specification (keyword 'ref'). c 's' Get Stokes/polarisations (keyword 'stokes'). c 'd' Perform input selection (keyword 'select'). c 'l' Get data linetype specification (keyword 'line'). c 'p' Apply planet rotation and scaling. c 'w' Return u and v in wavelengths. c '1' Default number of channels is 1. c 'x' Data must be cross-correlation data. c 'a' Data must be auto-correlation data. c 'b' Input must be a single file. c 'c' Apply gain/phase and delay corrections. c 'e' Apply polarisation leakage corrections. c 'f' Apply bandpass corrections. c '3' Return w in the preamble (as preamble(3)). c parameters below for SMA data handling c 'z' Handling all SMA spectral data. c '0' Handling Ch0, the super-continuum data, alone. c 'y' Handling If1 for the 1st IF (first 24 chunks from the DB correlaror). c '2' handling If2 for the 2nd IF (2nd 24 chunks from the DB correlaror). c parameters below reserved for the upcoming SMA wideband correlator data w1 and w2. c '4' handling w1 for the first wideband window (the 49th chunks from the wideband correlaror). c '5' handling w2 for the first wideband window (the 50th chunks from the wideband correlaror). Peter Teuben has agreed the above changes to be adopted in Miriad uv data handling routines. SMA will use the latest Miriad CVS (4.3.4 starting 2012-8-13) as the base to integrate the SMA changes and new tasks back to Miriad-CVS. SMA is required to test the merging codes before CVS submitting them to Miriad-CVS system managed by U. of Maryland. Peter T. will open a new branch in the Miriad-CVS tree to accept SMA's updated codes in the way as we had earlier for the 2GHz SMA data software (Miriad-cvs 4.0.5, 2008).
Jun-Hui Zhao Astrophysicist at SAO 60 Garden St., MS 78 Cambridge, MA 02138 Tel: 617 496 7895 Email: jzhao@cfa.harvard.edu