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NGC 6992 "bone hand"

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Posts Made By: John Neufeld

November 5, 2011 10:34 AM Forum: TeleVue

Televue MPT

Posted By John Neufeld

was anyone watching at the end of the auction?

February 19, 2016 02:22 PM Forum: Telescope Making

41.75" (1060.45mm) reflector

Posted By John Neufeld

If you are curious still about this material, there is a way to gauge its refractive index.

Get some liquids that are close to you suspected materials list, and make some pools of them on the surface.

If the reflection from the liquid/glass interface is very dim or non-existant, you can reasonably infer its index to be close to that liquid.

Zerodur and quartz can be almost clear or in the case of Zerodur, nearly white. I own the old 24" primary from the Innisfil Observatory. Its primary, a 24" Zerodur from a f/11 DK is almost clear.

April 25, 2018 03:27 AM Forum: Maksutovs

February 17, 2019 09:13 AM Forum: Antique/Classic/Vintage Optical Instruments

45 deg. Erecting Image Diagonal Prism for Quantum 4

Posted By John Neufeld

If I'm not mistaken if you thread off the erecting prism off the back of the cell the threaded attachment it goes onto is an m42 threaded attachment like old camera lenses. You could also go on cloudy nights as there is currently in the classics section a thread pertaining to the quantum for and there's a number of owners who have chimed in

November 25, 2019 05:20 AM Forum: N.A.S.A.

Oreo to celebrate moon landing 50th with limited edition cookies

Posted By John Neufeld

Maybe they could celebrate by making the Oreo cookies with the same amount of filling that they used to do 10 years ago before it started shipping out on the whole thing?