[daip] SETJY

[Eric Greisen]

Andreas Brunthaler wrote:
> Dear Eric,
> 
> I hope you are all back at work now in Socorro. I'm having some problems 
> with the velocity calculation in SETJY. I compared the results I get 
> when using the 31DEC2011 and the 31DEC2013 versions and get different 
> results for the same input parameters.
> 
> I'm using OPTYPE '' and the following information:
> 
> SYSVEL       18
> RESTFREQ   6.668E+09   519200
> VELTYP     'LSR'
> VELDEF     'RADIO'
> APARM       501,0
> 
> Now, If I use the 31DEC2011 version, I get in the SU table:
> 
> 
> COL. NO.            2                18                19
>       ROW      SOURCE            LSRVEL            RESTFREQ
>    NUMBER                        M/SEC             HZ
>         2      G000.31-0.20      1.978371D+05      6.668519D+09
> 
> 
> In the 31DEC2013 version, I get:
> 
> 
> COL. NO.            2                18                19
>       ROW      SOURCE            LSRVEL            RESTFREQ
>    NUMBER                        M/SEC             HZ
>         2      G000.31-0.20      179825.49691      6668519456.0
> 
> 
> If I use OPTYPE = 'VCAL' in the 31DEC2013 version, I get yet another value:
> 
> 
> COL. NO.            2                18                19
>       ROW      SOURCE            LSRVEL            RESTFREQ
>    NUMBER                        M/SEC             HZ
>         2      G000.31-0.20      233796.30089      6668519456.0
> 
> Apart from the different values I also get a different format. Now, if I 
> run CVEL on this, I get shifts of < 1 channel for the 31DEC2011 version 
> (as expected). However, for the 31DEC2013 version, I get shifts of 50 
> channels (using OPTYPE='') and 100 channels (using OPTYPE='VCAL'), which 
> corresponds to the velocity offsets above.
> 
> Any idea where this difference comes from?
> 
> Andreas
> 

I see some of what the issue is - the TST version does not include your 
18 km/s offset at the specified channel with opcode ' ' and there seems 
to be 2 * 18 km/sec offset with VCAL although I have yet to try to find 
where that comes from.

The OLD version did not do OPTICAL correctly with OPCODE ' ' but did do 
RADIO okay.  And, of course, VCAL is new and may know nothing about 
offsets in velocity and reference pixel.  I will look.

Eric