[evlatests] Fwd: missing panel pics

[George Moellenbrock]

Oops, Vivek points out to me that it was actually *ea20*.  ea21 was on 
*N01*, which is inline with the W arm and so not visible from the 
webcam, and I mis-labeled my initial email to ops/wye about the missing 
panel, assuming the first visible pad on the north arm was N01 (ea20).  
(I was looking at the webcam photos that morning for a timelapse of the 
move.)

The antenna which lost the panel was on the first visible (i.e., 
unobscured by antennas on the west arm) pad on the north arm, which I 
believe to be N02, and this was, indeed, ea20, *not* ea21.

Sorry for the confusion.  (Alas.  That would have been too neat an 
explanation!)

Curiously, however, although ea20/N02 was one of the first to move in to 
D-config (on Oct 24, apparently), it apparently doesn't get a position 
update until Nov 17/18, more than 3 weeks after it moved.  It was stowed 
for a ~day (until the panel was retrieved), but it did observe the next 
day (see photo in previous note), and presumably through early 
November.  The total position error on Nov 17 was 2.2cm....

(I wonder what the ea20's holography looks like?  Was the panel 
re-mounted to better than a few mm??)

-George


On 7/9/20 12:21 PM, George Moellenbrock wrote:
> Here's some pics I sent to Bryan documenting the missing panel, and 
> the weather that caused it.
>
> Not quite clear it is at one of the 'cardinal' points on the edge.
>
> And it can't explain both of your bad edge panels in the holography, 
> of course!
>
> -George
>
>
>
> -------- Forwarded Message --------
> Subject: 	missing panel pics
> Date: 	Thu, 31 Oct 2019 09:24:42 -0600
> From: 	George Moellenbrock <gmoellen at nrao.edu>
> To: 	Bryan Butler <bbutler at nrao.edu>
>
>
>
> Hi Bryan-
>
> I attach some pics of the missing panel.
>
> missing_panel2.jpg is an early close-up (when I noticed the missing 
> panel; someone else had zoomed the camera)
> missing_panel3.jpg shows the panel lying near the center of the dish 
> to the left of the feed housing.
> missing_panel5.jpg shows the panel has slid to the edge of the dish; 
> at this point, Vivek and I called the operator to have the antenna 
> stowed and the panel retrieved
>
> BeforeAfter.gif toggles between UTC=150859 and 150910, which shows 
> when it actually happened: ~9:09am MDT. (Enlarged from web cam photos 
> I was capturing at a wide angle to observe the move into D-array--alas 
> frustrated by the wind.)
>
> WindPlot.png is the weather station wind plot which shows that the 
> wind reached it peak sustained level (~40mph, gusts to 50mph) at the 
> same time.  Apparently, the whole array got a panel mount integrity 
> test for ~2 hours, at least for the WSW facing edges.....
>
> NextDay.jpg shows the antenna observing with the absent panel.
>
> Chris and Ephraim have photos from the site guys from inside the dish, 
> showing some impact damage to another panel, and a view out through 
> the gap.
>
> -George
>
>
>
>
>
>

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