[daip] EVLA and CVEL

[Amy Mioduszewski]

Hi Alet,

Sorry it took me a couple days to get back to you.  Without your CVEL inputs I 
have to guess at several things.  My first question is why you are doing CVEL if 
your frequency, as I read it, is already correct at 1665.54278?  Is the problem 
with the Doppler change throughout the observation?

Anway, to answer your original question, given the information you have 
provided, I think the APARM should be set to -7.4e3, 64, 0, 1665e6,402e3.
Note that rest freq=aparm(5)+aparm(6).

Amy

Alet De Witt wrote:
> Good day!
> 
> I please need some help with old evla L band spectral line, maser data. I have created single source SPLIT files. Doppler tracking was not used at the time of observation in 2007.
> 
> I thus need to run CVEL, but I am not sure what the inputs should be. The original setup for the observations was restfrequency 1665.402 and LSR velocity of the source observed -7.4 km/s.
> 
> Looking at the data I have  channel 64 at 1665.54278.  If I check the online doppler tool with the coordinates of the source  and day of observations and velocity of source (-7.4km/s ),  I get the same frequency (1665.54278)  as output.
> 
> I know that I have to set aparm(1-6) to make the corrections, but I am not sure exactly which values should go where? I keep on getting warnings of large channel shifts.
> 
> Could you please assist me in this regard.
> 
> Thanks you!!
> 
> 
> Regards,
> Alet de Witt
> 
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