Re: ATM Colimnating a Newtonian with a perforated mirror?

[deepsky <deepsky@usmo.com>]

If you want to be able to collimate the secondary and the primary easily and quickly get 
one of the
new holographic laser collimators.  We use one on our clubs perforated 30" f/4 dob and it 
works
great.
Mark

Nick Martin wrote:
> 
> Dear list,
> The astronomical society to which I belong has been given access to a very
> nice 12" Newtonian. The only problem is that the mirror is perforated,
> presumably for use as a Cassegrain or similar. It is optically good but the
> problem is how to colimnate it, other than doing a star test. A centre spot
> is clearly impossible.
> Nick
> Nick Martin, Bonnyton House, By Ayr, Ayrshire KA6 7EW ,Scotland, UK.
>  Latitude 55 24'56" Longtitude 4 26' 00".
> "Eppur si muove" Galileo Galilei

-- 
˙WPC