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progress on my first mirror

Started by BABOafrica, 08/07/2013 11:06PM
Posted 08/07/2013 11:06PM Opening Post
It's been a while since I reported on my first attempt at mirror making.

I started a year ago, working on and off, with a 12.5" pyrex blank.

It took me 20 hours to polish out using CeO on a slightly-less-than-full-sized pitch lap.

I've been doing some figuring since then.

I include some images that I took with a camera in the workshop -- they give an idea of where I stand after my latest figuring session.

The mirror has a few minor scratches -- nothing that makes me want to go back to fine grinding and 20 more hours of polishing.

Here's the Ronchigram (outside RoC). (It's a f/6.3 mirror: D=318mm / FL=2002mm)

Clears,
Joe

Attached Image:

BABOafrica's attachment for post 57684

In lumine tuo videbimus lumen.

8O Home-made 10” Dob / Home-made 4” refractor

EPs: Konig 32mm (1.25") / Zhumell WF 30mm (2") / Nagler 13mm T1 / Orion Sirius Plossls 25 & 10mm / Zhumell Plossl 9 mm / Meade MA 9mm
Posted 08/07/2013 11:07PM #1
Here's a picture taken during the Foucault testing.

Attached Image:

BABOafrica's attachment for post 147430

In lumine tuo videbimus lumen.

8O Home-made 10” Dob / Home-made 4” refractor

EPs: Konig 32mm (1.25") / Zhumell WF 30mm (2") / Nagler 13mm T1 / Orion Sirius Plossls 25 & 10mm / Zhumell Plossl 9 mm / Meade MA 9mm
Posted 08/31/2013 12:46PM #2
Joe,
Could I ask how many hours of actual grinding you've done. I just got my hands on a 12.5" pyrex blank and am starting to wonder how many hours of pushing glass I've got in front of me. This'll actually be my second mirror. I did a 6" f/8 last year, and it took - from grinding to figuring - 45 hours or so.
David

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ATM 6" f/7.7 Newt on Dob Mt

Celestron OMNI 102mm ED Refr.