Folded refactor plan

[OzEclipse (Joe Cali)]

Hi Chris,

Sorry, I have not checked back into this thread for a while and didn't see the post to say I forgot the photos.

Here's a couple of photo's of Glenn and his folded Nikon 5" f12 ED folded reflector. The scope only contained one high precision D&G optical 4 inch flat and so the camera looked in the opposite direction to the objective. The box was a little less than half the 60 inch focal length thanks to the camera and the objective sitting outside the box. The objective was removed and secured in a padded holder inside the box for transport.

In the second photo, Michael Gill is helping Glenn align the 400mm telephoto lens & camera on top of the box, with the optics in the box. This served as a finder and a wide field camera.

We positioned ourselves 160km from the end of the eclipse path so the sun was only 2 degrees above the horizon and the box horizontal. Totality lasted 18s and so he didn't worry about tracking. For longer overhead eclipses, he had another 6" high precision flat built into a heliostat that would keep the image of the sun in field of the refractor for the entire duration of the eclipse. In those cases, he did not have the wide field camera & lens mounted on the box.

cheers

Joe

[chrisp9au (Chris)]

I'm thinking of having another go with this project.

Firstly I'm going to acquire some quality first surface mirrors.
I understand 1/20th wave is the best quality, least error, to aim for?

I need a couple, one 65mm diameter, one 35mm diameter.

Any suggestions on the best source for these would be appreciated.

Then, if they show that the objective is poor quality, I'll acquire a better one.

Thanks for looking...

[Leo.G (Leo)]

I thought this project was becoming a sun thingie?
Chris perhaps you could discuss mirrors with Stefan Buda, I very much get the impression he's an optical and engineering genius.

[chrisp9au (Chris)]

It was going to be a sun 'thingie' Leo, but I am so easily distracted!

I get into my box(s) of bits and pieces, find something I've forgotten about, and a new journey starts!
I found a 2" extension piece with a different thread, then found that it fits a helical focuser I also had in the box, so my brain takes off...

My sun 'thingie' seemed like a lot of effort to just look at the sun, why not set it up to do more?
Who knows what I'll finish up with!

In the meantime I found a piece of anodized aluminum that could make a decent handle for my refractor...

Happy days

[Leo.G (Leo)]

Sorry Chris with the "thingie", my memory isn't what it was.
Ah, Sun spotter, exactly one thread below this one (I need better glasses).

"the old grey mare just ain't what she used to be"
I think that's what that song was about.
Speaking about looking at the sun, I still have the original attachment which came with a new Tasco back in the late 80s, a 17TR, 80x900 refractor (now shorter with several mods) and it came with the white plate and rod to set up and reflect the sun off to view it, it was a great idea for enjoying the view without the risks and worked extremely well.


I'm easily distracted and have a lot of junk to play with. I'm going to buy some 60mm round stock (6061 likely) and make a few adapters up on the lathe. I have to check my thread cutting capabilities, the lathe will do it semi automatically but I have no idea how to use that, my son does, I bought the lathe for him and just do quick, manual rough stuff. I really need to start playing with aluminium anodising though, anodising would be good. I used to do it for a living a LOT of years ago (early 80s), that and zinc plating but I never had to mix the chemicals.
I NEVER play with mirrors for fear of seeing my own reflection, NASTY!