[evlatests] WIDAR Map rotation

[Barry Clark]

>     X-band is unique in that it is of opposite sideband from the other 
> bands -- so the frequency ordering coming out of the correlator are 
> reversed.  

Oh?  I thought the intent was to set the sideband flippers so that the
direction of the spectra would be the same at all bands.  Is this not
being done?  Should it not be?


Rick Perley wrote:
>     I reported some time ago that images made with WIDAR data showed the 
> sky rotated by 180 degrees from the correct orientation.   This means 
> the data being gridded are the complex conjugate of the correct values 
> (phases are negated), since the baselines are known to be correctly 
> described. 
> 
>     The above were determined from L and C band observations.  It turns 
> out that this map rotation characteristic is *not* true at X-band -- 
> data taken of 3C273 last night are correctly oriented. 
> 
>     X-band is unique in that it is of opposite sideband from the other 
> bands -- so the frequency ordering coming out of the correlator are 
> reversed.  
> 
> 
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