[daip] Error running SDVEL

[Jeff Mangum]

Figured out the problem.  It was using the date in from the AN table you 
gave me.  Once I realized that the only place that it could get the 
absolute date information is from the AN table, which was "foreign" to 
these data, I simply used PUTTH to modify the date information.

I was sure that the aberrant frequency in the AN table was not a problem 
as SDVEL prints the frequency that it finds as part of its messages.  
You might consider added a print of the date (RDATE from the AN table) 
as part of the message output.

Anyway, I have a properly stitched data set now.  Thanks!

-- Jeff

On 5/9/08 10:33 AM, Eric Greisen wrote:
> Jeff Mangum wrote:
>> I have tried multiple combinations of DPARM all of which produce 
>> incorrectly-velocity-shifted maps.  At this point I suspect that this 
>> particular collection of data is the problem, not SDVEL.  I really do 
>> not want to fiddle with this any more.  How can I manually shift the 
>> velocity axes to make the image fields line-up?  Thanks.
>
> The short answer is that you can't.  The longer answer depends on what 
> the telescope did.  I am about to go off on a vacation and am working 
> on a pressing matter affecting a lot of VLA observing time.  I do not 
> have time to look at this now.
>
> The issue is - in one OTF field, the telescope may or may not have 
> changed frequency while observing.  But each position will have a 
> spectrum with a different velocity than its neighbor for a particular 
> channel all within the same field.  So it is wrong to label the cube 
> in velocity - but with many of the modes that the 12m used, it is also 
> wrong to label it with frequency since it did change frequency some at 
> points within the observation.  So I dod not know what to do with this.
>
> Note - in about 2 weeks I might have time to really look at this.  But 
> not until at least then.
>
> Eric