[daip] Re: One more CLCOR question

[Leonia Kogan]

>
>
>>>>Let me re-pharse my question.  If there is only one entry for
>>>>an antenna, will that result in a constant atmospheric (or clock)
>>>>correction, even if there input file has non-zero rate values?
>>>>        
>>>>
Mark,

When you asked about constant atmospheric (clock)  correction, I thought 
about correction
to the DEL column of the CL table! Yes, YES, YES this correction is 
constant if there is
only one entry for the given antenna. I'd say even more the correction 
of both column DEL and RATE of the CL table is constant  if there is 
only one entry for the given antenna.

But that does not mean of course that the phase correction provided by 
the corrected CL table
is not constant neither time axis (DRATE*DT) nor frequency axis (DDEL*DF).

I hope I say clear enough now.

Leonia


   Because you answered my question with a "YES":  (Note the
word "constant...correction" in the question.)

Reid's question:

>>>>Let me re-pharse my question.  If there is only one entry for
>>>>an antenna, will that result in a constant atmospheric (or clock)
>>>>correction, even if there input file has non-zero rate values?
>>>>        
>>>>




Mark Reid wrote:

>Leonia,
>
>On Thu, 17 Nov 2005, Leonia Kogan wrote:
>
>  
>
>>>That would seem to imply that the RATE column in the CL table
>>>does nothing.  So why is it there?
>>>      
>>>
>>Why do you think that the RATE column in the CL table does nothing?
>>    
>>
>
>   Because you answered my question with a "YES":  (Note the
>word "constant...correction" in the question.)
>
>Reid's question:
>  
>
>>>>>Let me re-pharse my question.  If there is only one entry for
>>>>>an antenna, will that result in a constant atmospheric (or clock)
>>>>>correction, even if there input file has non-zero rate values?
>>>>>
>>>>>          
>>>>>
>Kogan's reply:
>  
>
>>>>The answer is YES.
>>>>        
>>>>
>
>
>  
>
>>As I understand the column RATE of a CL table having been applied to the
>>data corrects
>>the phase of the data adding RATE*DT. It is sort of approximation of the
>>phase from time of CL table to the time of the data.
>>
>>Now about the input file for opcode 'ATMO'. I have always considered
>>that the column DELAY (infile) is to correct DELAY column at the CL
>>table  and the column DERIVATIVE (infile) is to correct RATE column at
>>the CL table. This concept is used at CLCOR 'ATMO'
>>    
>>
>
>   I did the following test that seems to support the idea that
>the rate values in the CLCOR ATMO infile have little, if any,
>effect:
>
>   I fitted for 2 parameters each for the atmospheres and clocks
>and produced an input file for CLCOR with one entry per antenna.
>If the rate parameters are used to extrapolate from the one time
>given, then after fixing the data and re-fitting, the re-fit
>results should be near zero.  This was true for the vertical
>delays and clocks, BUT not for the re-fit rates which were close to
>the original values.   It would be good if you try this test
>(using DELZN and CLCOR) and see if you get the same results.
>The data set on my anonymous FTP site (see earlier email)
>is an excellent one for such tests.
>
>Mark
>
>=======================================================================
>
>  
>
>>Leonia
>>
>>
>>Mark Reid wrote:
>>
>>    
>>
>>>On Thu, 17 Nov 2005, Leonia Kogan wrote:
>>>
>>>
>>>
>>>      
>>>
>>>>>Let me re-pharse my question.  If there is only one entry for
>>>>>an antenna, will that result in a constant atmospheric (or clock)
>>>>>correction, even if there input file has non-zero rate values?
>>>>>
>>>>>
>>>>>          
>>>>>
>>>>The answer is YES. Non-zero rate value is used to correct the RATE column at the
>>>>CL table.
>>>>
>>>>
>>>>
>>>>        
>>>>
>>>  That would seem to imply that the RATE column in the CL table
>>>does nothing.  So why is it there?
>>>
>>>mark
>>>
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>>>Daip mailing list
>>>Daip at listmgr.cv.nrao.edu
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>>>
>>>
>>>
>>>      
>>>
>
>  
>