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Field flattener, Williams old one.

Posted: Wed Nov 24, 2021 5:29 pm
by Altocumulus
Does anyone have a William Optics 102GT with an old style flattener/reducer, and can post an image or two showing their setup so I can see how it all fits together.
This is the first time of trying to use the flattener, not needing it on solar stuff...

Back focus diagrams are all well and good, but often don't include the telescope and where the focus tube is....

Geoff

Re: Field flattener, Williams old one.

Posted: Thu Nov 25, 2021 11:12 am
by Altocumulus
If the 'normal' focus distance is 277.44 mm without the FF, and the
back focus for the FF is 69.9mm.

In normal solar work the distance is assisted by use of a solar wedge or CaK module - so I can only roughly guess I'm achieving the correct distance.

How much does the focus tube have to be 'out' from its housing, when the FF is included - would a diagonal make it any easier?

Geoff