[ATM] Star test with pin hole

["Ray@J-Engineering.com" <Ray@J-Engineering.com>]

Hi All,

I’m trying to star test an uncoated 8” f/6.3 mirror with a combination 
of a bright (amber-yellow, 7800 mcd) LED, around a 0.007” pinhole in 
aluminum foil, and about 180 feet between the pinhole and the mirror. 
I’m using Suiter’s book as a reference. I am finding steady air hard to 
come by and the air along the ground much steadier than overhead, thus, 
an artificial star makes sense. All I can get right now is 260 power. I 
believe I’ll need a brighter source since it is hard to expand the image 
to about ten waves. Five waves are OK.

Some observations are:
The real stars above are much brighter than my source.
In the focused image I can see the first diffraction ring and 
occasionally parts of a second.
The focused pinhole looks like a small disk, it is not stellar.

Are these observations normal?

Ray J


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