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Re: ND1000 filter - a data point
From: Bill Ritchie
Date: 2022 Oct 30, 18:24 +0000
From: Bill Ritchie
Date: 2022 Oct 30, 18:24 +0000
Tony,
Does this article explain the image shift when using an optically flat polarised flter?
Bill Ritchie
On Sun, Oct 30, 2022 at 12:47 AM Tony Oz <NoReply_TonyOz@fer3.com> wrote:
Dear Noell,
My attempts involved a japanese-made filter, not a bit of arbitrary glass.
Instead of grinding the glass - I used a spare shade-frame of a broken shade. Its' internal diameter was slightly less than the filter's thread, so I milled the frame's metal instead. I sort of "threaded in" the filter into the frame - with some friction, secured it with a drop of glue.
Alas, despite the quality of the filter, there were several arc-minutes of image shift when I rotated the polariser to adjust it to the glare conditions.
So - beware!
Warm regards,
Tony
60°N 30°E
