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Explore Scientific AR152 152mm f/6.5 intrusive o-ring in objective

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#1 RichA

RichA

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Posted 22 February 2021 - 09:05 PM

I got a lens from one of these and noticed that the elements were reversed from what I thought

so I had to remove it from the cell and flip the elements.  Part of the reason I had to do this was

that there was only one, skewed air space tab.  The newton rings were off-centre by 1.75 inches.

Removing the tab and  replacing them with three equal-spaced ones reposition the newton rings

into the centre of the lens.  There was an o-ring (which I got rid of)

that was impinging on about 2mm of aperture.   It wasn't needed (since an objective isn't supposed to

be locked-in tight by a retaining ring anyway.  There was enough thread to screw it down properly.

The o-ring was interesting.   It smelled.  It was a dark-green plastic but it smelled strongly of (kind of like) vinyl. 

The ring was malleable, with little "memory."




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