[ASA] resumption of AAT observing

[Warrick Couch]

Dear colleagues:

On the 17 March, I sent out the message below informing you of the
suspension of observing on the 3.9m Anglo-Australian Telescope (AAT)
due to a major failure with its dome shutter.

I am pleased to advise that the dome shutter has now been repaired, and
normal observing resumed again last Friday night, 27 March. 

The only outstanding work remaining to be done on the dome shutter is to
replace its rollers, which are rather worn. This will be done sometime in
the next month by our AAO staff, and will not involve any disruption to
observing.

For those of you interested, pictures of the recent repair work done on the
AAT dome and its shutter can be seen at:

https://www.aao.gov.au/public/images/dome-shutter-repairs-photos

Warrick Couch
(AAO Director)



Begin forwarded message:

> From: Warrick Couch <Warrick.Couch at aao.gov.au>
> Subject: [ASA] temporary suspension of AAT observing
> Date: 17 March 2015 4:59:42 PM AEDT
> To: "asa at physics.usyd.edu.au" <asa at physics.usyd.edu.au>
> 
> Dear colleagues:
> 
> This is to inform you that observing on the 3.9m Anglo-Australian Telescope (AAT)
> has had to be suspended, due to a major failure with the AAT dome shutter. 
> 
> Towards the end of last year, it was discovered that a section of one of the
> arch girders that support the dome and which the shutter runs along, was
> damaged. The most conspicuous evidence of this was a delamination of
> the girder, causing metallic flakes (some quite large) to rain down on the
> telescope and dome floor beneath. It is almost certain that this can be
> attributed to the stiffness of the new dome shutter brake system installed
> in 2012, which has put additional stresses on the arch girder as the shutter
> moves over it, causing it to deform and the metal to fatigue. As such, an 
> engineering company had been contracted to rectify this problem and repair 
> the damaged section of the arch girder, with the work scheduled for late April, 
> during which observing on the AAT would be suspended for 7-10 days.
> 
> However, over this last weekend, the arch girder developed a major crack
> in the area where it is damaged, rendering the dome shutter inoperable. 
> We have therefore had to suspend observing immediately, and organise
> for the aforementioned engineering work to be done as a matter of urgency.
> Fortunately the company contracted to do the work can commence this
> Thursday (19 March), and are prepared to work extended hours and
> through the weekend in order to get the job done as soon as possible.
> It is hoped that the job will be completed by next Wednesday (25 March), 
> with the AAT operating again very soon thereafter. 
> 
> Unfortunately a minimum of 12 nights of observing time on the AAT will
> be lost. Steps will be taken to ensure that the scientific programs  
> affected will be appropriately compensated for this loss of time. 
> 
> I will follow this message up with a second announcement to notify
> the community when the problem has been fixed and normal AAT
> operations/observing have resumed.
> 
> Warrick Couch
> (AAO Director)
> 
> -------------------------------------------------------------------------------------------------
> Professor Warrick Couch FAA                                Phone: +61 2 9372 4811
> Director, Australian Astronomical Observatory   Fax: +61 2 9372 4880
> P.O. Box 915, North Ryde, NSW 1760  Email: warrick.couch at aao.gov.au
> -------------------------------------------------------------------------------------------------   
> 
> 
> 
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Professor Warrick Couch                                    Phone: +61 2 9372 4811
Director, Australian Astronomical Observatory   Fax: +61 2 9372 4880
P.O. Box 915, North Ryde, NSW 1760  Email: warrick.couch at aao.gov.au
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