Re: [ATM] Hello & Mak Newt specs

[Dale Eason <atmpob@yahoo.com>]

Yesterday I tested the spherical mirror of a similar
scope.  This one was a 6.25 inch diameter.  It too had
the same cell.  I tested it in the cell using a home
made interferometer.  The mirror was excelent but had
a little astig aligned with one of the screws that
hold that front ring on.  Under that screw are little
pads that press down on the mirror and keep it in
place.  Those screws were sealed at the factory.  The
astig in this case was only 1/20 wave PV on the
surface so I told him to leave it alone.

The strehl came out to be near .96.   Without the
astig the strehl would be near .98.

My robo Foucault and Sixtests measured a strehl of
.993.


Dale Eason

--- maxmirot@charter.net wrote:

> Sure ... will do shortly. 
>  
> It is interesting  just how this OTA was put
> together. I think it was a terrible 
> just job for 10K+ scope. One if the bolts holding
> the cell was mis-drilled. 
>  
> I bought it used so I am force to take on the
> modifications myself. If bought it 
> new , it would have been returned. 
>  
> The mirror cell is a bit odd. It has no flotation.
> Just a ring 3/8" thick by 3/4 
> " wide supporting the outer mirror at the bottom. 
>  
> The mirror cell has a thin front aluminum retaining
> ring about 3/8 wide over 
> which cover 2mm beyond the bevel.  
>  
> There are 3 nylon points are holding edge at the
> center of the mirror. I noticed 
> some pinching at the edge when I star testing. I am
> thinking of loosening them 
> and putting rtv around the edge of the mirror to
> keep from bashing into the 
> front retaining ring. 
>  
>  Any better ideas besides making a new cell? 
>  
>  The mirror is 35mm thick made of quartz. The
> corrector is also quartz 25mm 
> thick. 
>  
> The back plate had no fan but was cut and drilled to
> fit a 100mm fan. 
>  
> The dealer who put these optics in the CF tube
> claims it should not have a fan. 
>  
> Though he left the hole open in the back. He thinks
> the thermal effect from 
> cooling are bull. I disagree. 
>  
> I added the rear fan plus two smaller  fans with
> vents in . 
> front of the primary. 
>  
> Unfortunately, The corrector cell does not have the
> standard ring of holes seen 
> in the front on other Intes scopes. I am not sure if
> I  want or need to vent the 
> top of the air at the top of tube. Comments? 
> 
> 
> Max
> 
> ---- Dominic-Luc Webb <dlwebb@canit.se> wrote: 
> > I certainly look forward to watching your projects
> as they
> > advance... here is my website....
> > 
> > http://www.canit.se/~dlwebb/
> > 
> > Dominic
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 


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