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Springfield Mount

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Posted by Malcolm Bird on March 12, 2003 16:57:24 UTC


I have a old issue of an astronomy book (petersons fieldguide I think...) that shows a picture of the original Custer Springfield 12" Newtonian.

The secret is in the L shaped declination bearing - essentially a plate bearing with a central hole through which the secondary reflects the light rays to a star diagonal.

Because the dec shaft and polar shaft essentially intersect at the eyepiece, or close to it, the eyepiece stays in the same position regardless of telescope orientation. It would make a perfect sitting scope for people with back problems,etc..

Unfortunately, it is difficult to make very portable because of the counterweight issues. Also, it would not work well with short focus mirrors because the secondary needs to be positioned closer to the primary so you get more distance outside the tube to play with.... You could do it with a 6"F8 and a 1.5" sec - but any faster and you'll need bigger diagonals to field the light rays...

I plan on building one this summer. I'm tired of the bedn and squat routine...

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