Re: ATM 8" Achromat

["David Simons" <hmsimons@hotmail.com>]

I finally received my R. E. Brandt 8" f? achromat objective lens. It has 
come in a very strange long cell that I can't tell which end is the front!!

There is one side that appears to have push-pull alignment screws. I am 
guessing that is the front of the lens. This side appears to be convex while 
the back side seems to be concave. Does this sound right?
The spacing between the lenses is the thickness of a folded stamp.

Also I need a way to verify the focal length of the lens, I have a ~1/2 wave 
mirror I was thinking of reflecting the light of the sun or moon using this 
mirror through the lens and then using a tape measure to verify the focal 
length. Does this sound reasonable? Or is there a simpler way to do this?

My plan is to fold this design into something transportable. I haven't 
decided which optical path to use yet. I'm favoring a single mirror at the 
bottom to fold the FL in half.

Dave Simons
San Jose, CA


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