[ATM] 8" F/4.2 progress

[Jason Hissong <jhissong@gmail.com>]

Hi guys,

I just started figuring again..  I took a break from figuring to build 
the scope.  Here are some pictures of the scope close to being fully 
assembled:

http://www.undermidnight.com/images/atm/ball-scope-1.jpg
http://www.undermidnight.com/images/atm/ball-scope-2.jpg
http://www.undermidnight.com/images/atm/ball-scope-3.jpg
http://www.undermidnight.com/images/atm/ball-scope-4.jpg
http://www.undermidnight.com/images/atm/ball-scope-5.jpg

I took the plunge and finally purchased a nice Porter Cable router, 
circle cutting jig, and drill press.  It has made it so much nicer to 
build this thing.  I have never done any precision woodworking before so 
I made some mistakes, but things are finally fitting together nicely :)  
I wanted to get the scope together so that I can star test during the 
figuring.  I need to take a break from the building part because I am 
starting to get pretty fried.  There were a couple of nights where I did 
not get any sleep thinking of how to do various things with the design... 

Soooo... back to the mirror....

My mirror was slightly oblate (as you may recall) and the edge was a 
little turned down.  Well, I think I fixed the edge.. and after once 
around the turntable, my mirror is just about a perfect sphere...

http://www.undermidnight.com/images/atm/sphere_small.jpg

(The widening of the bands at the bottom are because of my camera lens.  
It looks like the bands at the top when I use my eye).

As you can see, I got the edge cleaned up.  It is amazing to see the 
difference in just one pass around the barrel.  I have read and re-read 
Mike Lockwood's material and it has really assisted in understanding 
this. (Thanks agian Mike).

So now I got this thing looking this good... I don't want to mess it up 
into a parabola... !!   But then I cannot use it as a scope!!  It's a 
catch 22...  :-)

I think I figured out why it is difficult for me to use the couder mask: 
the entire mirror nulls out at once!  It took me a little bit to realize 
that (I think I am right about this..)

Anyway, I am very excited on how this is turning out.  Mirror is just 
about pressed again.. back to another round of figuring...

Jason

-- 

"A long journey starts with the first step and an understanding spouse."
http://www.undermidnight.com - astronomy and astrophotography
http://www.n8xe.com - ham radio
http://www.jasonhissong.com - electronic music composition

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