[daip] RE: FRPLT and POSSM with SHIFT

[Vycheslav Slysh]

Leonia,
I know about FRMAP and use it frequently. As for FRPLT I dicovered that now
it has 'search shift' and tryed to test it but without success.
I use FRPLT as a check of the absolute position and some times do the search
for the shift manually. I thought that the new version can do it with a
special subroutine, and it seems to do a grid of shift positions, but as I
said I could not produce the result of the search.
Regards,
 Slava

> ----------
> From: 	[Leonia Kogan][SMTP:lkogan at aoc.nrao.edu]
> Sent: 	29 декабря 2000 г. 18:28
> To: 	vslysh at asc.rssi.ru
> Cc: 	daip at cv3.cv.nrao.edu
> Subject: 	Re: [daip] RE: FRPLT and POSSM with SHIFT
> 
> Slava,
> 
> You wrote:
> 
> >The new FRPLT provides an
> >option of the search for position shift. This is a very useful option
> which
> >can be used for determination of absolute coordinates as an alternative
> to
> >SAD. 
> 
> FRPLT does not provide a 'search shift'. It recalculates the UV data 
> to the new position of the tangent point. 
> 
> As I understand, you use FRPLT 
> to determine the position of the source component looking at the change of
> 
> the fringe rate.
> 
> AIPS has a special task for this purpose: FRMAP.
> This task create the map of the source based on the fringe rate change.
> The task works especially for spectral line sources where it create the
> image 
> relatively the selected  frequency channel. It can be used to make more 
> exact the absolute coordinate also. The last option is used for continum 
> source when its position has not known apriori with enough accuracy.
> 
> >However my first attempt with the 'search shift' option
> >was not successfull: it did not produce any output.
> 
> What does it mean? It does not produce any plot with the non zero shift 
> and make the plot with shift=0?
> Does FRPLT succesfully finish with nonzero shift or not?
> 
> I am not sure that you have the corrected version at your computer.
> I put it in both 'tst'=31DEC01 and 'new'=31DEC00, but I do not know 
> if MNJ serves your machine to make the changes. WE'll investigate it here.
> Or the changes has not come to you yet. Try it again later.
> 
> You can check the fortran codes:
> The corrected version has:
> 
>                   FRSCL = 1.0D0 + (FOFF(LOOPIF) + FINC(LOOPIF) *
>      *               (LOOPF + 1 - PBCHAN - CATR(KRCRP+JLOCF))) / UVFREQ
> The old version had:
> 
>                   FRSCL = 1.0D0 + (FOFF(LOOPIF) + FINC(LOOPIF) *
>      *               *(LOOPF - CATR(KRCRP+JLOCF))) / UVFREQ
> 
> The corrected version of FRPLT works at my machine here.
> 
> Leonia
> 
>