Re: [ATM] Double dob-newtonian diagonal?

[Charles Broward <cbroward@ufl.edu>]

Hugues,

How about trying this....

Take a electronic eyepiece and a small lcd monitor/television set.  
Total cost about $100 new.  Then a small crowd can watch.
This is what we (Alachua Astronomy Club) has done for transits, lunar 
observing,etc. 

And, use your idea of second diagonal, but for the TV image, and you 
keep the eyepiece image for yourself...

Where are you planning to go?

Clear Sky

Chuck in N. Florida

Hugues.Laroche@ses-astra.com wrote:
> Hello List,
>
> I am coinsidering to attend a total solar eclipse next year, and for this
> and the nights before/after I would like mount the optics I have into
> a travel dob... nothing new. But, at the crucial moment of totality,
> experience tells me there is a rush to fill people's eyes
> and also if possible take pictures through the telescope....
> I do not see this can be done in 2 minutes
> with a single focus telescope.
>
> So, what do you think of using TWO diagonal mirrors and have
> two parts of the focal planes reflected at distinct locations, so one
> could have an eyepiece and the other a photo device? 
>
> My idea to realise this is to use an undersized (40 mm minor axis) 
> diagonal
> in front of the normal (58 mm) diagonal, the primary being a
> 254x1200 mm paraboloid?
> Pro: the diagonals can be used as-is.
> Con: the spider suport of the first diagonal needs to be extremely thin
>
> An alternative is to have a cored flat diagonal and a normal flat behind.
> Pro: no spider vane problem
> Con: Cored diagonal is not off-the-shelf
>
> All this needs to be as lightweight as possible, of course!
>
> Thanks for any thought/criticism!
>
> In particular, it might still be better to have a small instrument
> piggy-backed on the dob with a camera...
>
> Hugues
>
>
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-- 
--------------------
Chuck  Broward

"If you think you are too small to make a difference,
try sleeping in a closed room with a mosquito."



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