Hogging out the primary for a 12" Cassegrain

Hogging out the primary mirror of a 12" Cassegrain telescope.

Aushöhlen des Hauptspiegel-Rohlings für ein 12" Cassegrain Teleskop.

See http://www.hobby-werkstatt-blog.de/amateur-telescope-making/41-miranda-hoggin... for deails.

Category:

Howto & Style

Tags:

• telescope
• making
• atm
• diy
• cassegrain

[OghamTheBold]

Isn't ground glass poison? (Don't eat it in case). Talk to those CNC guys - they could automate that stuff - it'd take all the hours of fun out of it though

[otterstedt]

Yes, glass dust is a very dangerous stuff! That's why I grinded "under water". My additional breathing protection literally scared the cat away ;-) You'll find an image on my blog (see a link in the description of this video)

[otterstedt]

Hi qwerty9321, the tool I used is based on grit. I've got one of these diamond tools as well, but I was a bit afraid of going to deep ;-) So I used the "slow" tool.

[otterstedt]

Argh, my comments don't show up. Hope this one does ;-) I think the tool is called cap washer or cup washer in Englisch. In German it's called Topfscheibe.

[IcechickenSr]

@otterstedt I'll never forget this, my mom's friend when I was younger came over in agony and I guess she had done a little cocaine, her sinuis' were black and blue on the outside, she could hardly breath, and was in total complete agony. I remember my mother taking her to the hospital and she actuall had to have surgery to have it cleaned out. Turnes out she had got into somebad cocaine and the primary ingrediant was Glass! She had mercury poisining or something similar. Bad stuff glass LOL.

[foreilly1958]

Interesting. I notice that you are working on the ground. Might a table be useful? How is your project coming along now?

[musherX]

This is a beautiful project. I really want to know more. The story sort of stops at drilling the center hole of the primary. Have you done more since?

[joshig1983]

It must be incredibly difficult to make a short focal ratio primary mirror hyperbolic like that. Is your Ritchey Chretien going to have a longer tube than usual so your mirrors can be more flat and aberrations become less noticable?

[joshig1983]

otterstedt said: "What I'm working on, is a Ritchey Chrétien Cassegrain without a front corrector"

What do you mean by not having a front corrector? You mean you aren't having a corrector lens plate because Ritchey Chretien doesn't need one, right?

[myronww]

Do they make air powered grinders you could use to do this. Using an electric grinder while standing in a puddle of water increases your likelyhood of electrical shock.

[otterstedt]

Both have a front-corrector (Lens at the front end of the tube). Normally the corrector of the Schmidt Cassegrain is thinner.

BTW: What I'm working on, is a Ritchey Chrétien Cassegrain without a front corrector ;-)