Date: Wed, 3 Oct 2012 06:28:49 -0400 (EDT)
From: Jun-Hui Zhao 
To: Alice Argon 
Cc: thunter@nrao.edu
Subject: Re: SMA frequency scale as interpreted by CASA

Hi Alice,
     I forgot to mention that the IDL-Miriad path has been
problems. We had two meetings in past month for sorting out
the well-known mess in the IDL output,
http://www.cfa.harvard.edu/sma/miriad/download/userMtg/IDL/
     Charlie Qi agrees to work on it after his a week leave.
     Jun-Hui

On Tue, 2 Oct 2012, Jun-Hui Zhao wrote:

> Hi Alice,
>     The SMA frequency-velocity system was a bit confusing.
>     Quite a few problems were reported in the past (in SMA log and
> email communications); some of them were listed in Todd Hunter (ALMA)'s
> wiki page.
>     Miriad-path made special routines of correcting those errors.
> Todd Hunter was involved in the early development of SMA Miriad.
> Unlike NRAO dopset and fixed sky-frequency at transit, Miriad uses
> the true sky frequency and doppler-velocity in handling
> velocity-frequency conversion. We have correctly converted
> SMA online frequency-velocity to Miriad-system.
>     Jun-Hui
>
> On Tue, 2 Oct 2012, Alice Argon wrote:
>
> > Hi Jun-Hui,
> >
> > There appears to be a problem with the frequency scale when reading
> > calibrated SMA data into CASA.  See NRAO public wiki:
> >  https://safe.nrao.edu/wiki/bin/view/Main/SMAVelocityScale
> >
> > The wiki then talks about "query[ing] the SMA database for the velocity
> > being tracked at source transit" and correcting using NRAO's dopset.
> > Is there a MIRIAD fix that would accomplish the same thing?
> >
> > Thanks,
> >  Alice
> >