Re: [ATM] ATM edge support

[jjdubois <jjdubois@insightbb.com>]

There was even one of the segments with actuators attached on display as 
you walk into the building housing the Hobby-Eberlle when I was there 
last year.  How can segmented spherical mirrors on actuators ever come 
to a good focus.  The MMT on mount Hopkins has had the segmented mirrors 
replaced with solid mirror.

 Isn't it the 107 that has the bullet holes in it? 

Jule J. DuBois

Jarvis Krumbein wrote:

>Sorry, but the Hobby-Eberle is not an 11 meter f1.5 sphere.  It is a
>collection of 1 meter spherical hex shaped (approximately 16.5 meter
>focal length) mirrors which share a common focus to increase the light
>collection.  When I visited the site six or seven years ago, I was
>surprised at the lack of knowlege of the guides who didn't seem to know
>anything about the instruments they were showing.  We weren't allowed to
>see the 82" at all and were kept at arms length from the 105"?.
>
>Jarvis Krumbein  < jkoptic@juno.com>
>
>On Mon, 9 May 2005 20:35:33 -0500 "The Alarm Co." <tac@i1.net> writes:
>  
>
>>I just toured the McDonald Observatory (part of the Texas Star Party
>>festivities) and got a good look at the back end of the 107" scope.  
>>It has
>>an astatic cell with about 30 points (the guide wasn't sure of the 
>>exact
>>number) that looked pretty ordinary.  Here's the interesting thing:  
>>the
>>edge supports are also astatic.  It looked like there were about 10 
>>points.
>>Since it's on a equatorial mount,  the astatic design should 
>>automatically
>>compensate for the variable orientation of "down".  Sounds like a 
>>viable
>>alternative for those who don't want to glue their mirrors in or 
>>resort to
>>multiple slings.
>>I also toured the Hobby-Eberle.  Here's a puzzle (one the guide 
>>couldn't
>>answer).  Its primary is an 11 meter f/1.5 sphere.  How much 
>>difference in
>>sagitta would there be if it were a paraboloid? (answer withheld as 
>>an
>>exercise for the reader, and also because I haven't figured it out 
>>yet)
>>
>> *  Best regards, Bob
>>*
>>         *           *   *
>>
>>            *         *
>>
>>
>>_______________________________________________
>>ATM mailing list http://www.atmlist.net/
>>
>>    
>>
>
>_______________________________________________
>ATM mailing list http://www.atmlist.net/
>
>  
>
_______________________________________________
ATM mailing list http://www.atmlist.net/