White Light Solar Dob?

[colinsk]

Dobson described a solar dob made from uncoated mirrors. As anyone used or built one?

[colinsk]

Thank you! I had not seen that.

It is nice that it eliminates the obstruction. I wonder if you AR coated the first mirror for H-alpha if you could make an obstruction free mirror based h-alpha scope? In LASERs we have mirrors HR and AR coated for different frequencies simultaneous often.

[Photonist]

Hi,

These uncoated mirror Newtonians are not actually on Dobsonian mounts, but interesting anyhow. Sorry, if I’m a bit out of topic.

I have been planning to build something in this Art Whipple truss rod style using a 200-250 mm mirror (only for imaging). Let’s see…

If I only could get it light enough for my mount. What do you think of the design? The field stop could be a good idea.

http://tinyurl.com/8863u3w
http://tinyurl.com/d52joxr

Best wishes,

Viljo

[colinsk]

If you enclose links with the url button above the editing box they will work with a tilda.

[colinsk]

Why not un-aluminize the secondary? Then we get 5% of 5%. That is .25%. Much better. Then we use a ND3 to 4 filter and we are visual. Hmmm....

[Photonist]

Hi,

Yes, I also wondered about his secondary as there is certainly enough light if using an unaluminized one. I haven’t even considered an aluminized secondary.

Interesting that he had no reflection problems due to the white mirror cell.

I wonder if a bit cheaper quality mirrors would do (Whipple used 1/20 λ)?

Viljo