[daip] multi-channel continuum calibration

[Eric Greisen]

Farhad Zadeh wrote:
> Hi Eric,
> We recently observed Sgr A* using EVLA at 7mm in the A-array using
> 2x1Ghz band as the headers below show.
> We combined the data using avspc and then proceeded  calibrating  the 
> data following self-cal (P and A&P)
> Turned out the imaging quality is really bad and can't see any extended 
> emission except Sgr A*.
> 
> I am suspecting that because of the delay across the
> band and the consequent poor  deconvolution that we are getting
> terrible images. Any suggestions as to we should proceed properly
> (step-by-step including  self-cal on channel data above).
> 
> Many thanks,
> Farhad
> AIPS 1: Image=MULTI     (UV)         Filename=DAY1-COR    .TYAPL .   1
> AIPS 1: Telescope=EVLA               Receiver=EVLA
> AIPS 1: Observer=Dr. Farh            User #=  777
> AIPS 1: Observ. date=09-JUL-2011     Map date=05-AUG-2011
> AIPS 1: # visibilities   3474549     Sort order  TB
> AIPS 1: Rand axes: UU-L-SIN  VV-L-SIN  WW-L-SIN  BASELINE  TIME1
> AIPS 1:            SOURCE  INTTIM
> AIPS 1: ----------------------------------------------------------------
> AIPS 1: Type    Pixels   Coord value     at Pixel     Coord incr   Rotat
> AIPS 1: COMPLEX      3   1.0000000E+00       1.00  1.0000000E+00    0.00
> AIPS 1: STOKES       4  -1.0000000E+00       1.00 -1.0000000E+00    0.00
> AIPS 1: FREQ        64   4.1436000E+10       1.00  2.0000000E+06    0.00
> AIPS 1: IF           2   1.0000000E+00       1.00  1.0000000E+00    0.00
> AIPS 1: RA           1    00 00 00.000       1.00       3600.000    0.00
> AIPS 1: DEC          1    00 00 00.000       1.00       3600.000    0.00
> AIPS 1: ----------------------------------------------------------------
> AIPS 1: Coordinate equinox 2000.00
> 

Please see Appendix E of the CookBook - you cannot do what you did.

http://www.aips.nrao.edu/cook.html

will take you to it.

Eric Greisen