Welcome to East Midlands Stargazers

Register now to gain access to all of our features. Once registered and logged in, you'll be able to contribute to this site by submitting your own content or replying to existing content. You'll be able to customise your profile, receive reputation points as a reward for submitting content, communicate with other members via your own private inbox, plus much more! This message will be removed once you've signed in.

Graham

Secondary Mirror holder.

23 posts in this topic

 

Knocked this up at work today whilst I was waiting for the water jet to do its thing.

 

This is the test rig secondary mirror holder.

Decided to make what I hope is an improvement on the standard design with a little idea of my own.

 

The workings.

 

Secondary mirror holder 1.jpg

 

Another View.

 

Secondary mirror holder 2.jpg

 

The complete thing.

 

Secondary mirror holder 3.jpg

 

How it works.

 

 

Edited by Graham
Brantuk, Bottletopburly, Ibbo and 1 other like this

Share this post


Link to post
Share on other sites

Ingenious Graham 👍

Nicely demonstrated too!

 

Dumb questions...

Have you tried it with the screw tensioners in place?

There are no tension springs, so is it easy to alter the tilt, loosening one screw, tightening another etc, without loosening the ball bearing too much? 

Graham likes this

Share this post


Link to post
Share on other sites
1 minute ago, Smithysteve said:

Ingenious Graham 👍

Nicely demonstrated too!

 

Dumb questions...

Have you tried it with the screw tensioners in place?

There are no tension springs, so is it easy to alter the tilt, loosening one screw, tightening another etc, without loosening the ball bearing too much? 

 

Hi Steve

Yes it is all tried and tested.

I am using M6 bolts which will be replaced by Allen bolts.

By drilling the holes in the base section at 8mm it allows for full movement of the holder around the ball bearing.

Since posting I have now sprayed it up Black and will shortly be attaching the mirror.

Share this post


Link to post
Share on other sites

Fabulous idea Graham - why has no one thought of that before?

Nice one! :)

Graham likes this

Share this post


Link to post
Share on other sites

That's how I have designed my primary mirror cell with one large ball bearing as a pivot.

 

Your idea should work well.

Graham likes this

Share this post


Link to post
Share on other sites

Thanks Kim.

I have no idea it just seemed the perfectly logical way to do it.

Normally there is a central bolt but as I don't have that issue.  :)

I will do it the same way when I build the scope.

Brantuk likes this

Share this post


Link to post
Share on other sites
10 minutes ago, Doc said:

That's how I have designed my primary mirror cell with one large ball bearing as a pivot.

 

Your idea should work well.

 

Sounds interesting Mick.

I would like to see a photo of that. :thumbsup:

Share this post


Link to post
Share on other sites

 

The finished article.

 

Secondary mirror finished.jpg

Smithysteve and Brantuk like this

Share this post


Link to post
Share on other sites

Graham you are bloody genius. I can't believe the pace you are going at,  have you sorted out how the main mirror will attach to the truss and how the main mirror collimation will be achieved? I only ask because the main mirror connection and adjustment strategy on my monster binos appears pretty ingenius and is light years ahead of the  push/pull locking nuts I have had to play with on various scopes. I'm sure your come up with something as or more ingenius but I think the mechanism is worth a butchers....

 

 http://www.deep-sky.co.uk/telescopemaking/tm13.htm

 

John

Graham likes this

Share this post


Link to post
Share on other sites

Hi John. 

If you take a look at the test rig build the cell and it's collimation attachments are on there. 

Share this post


Link to post
Share on other sites

Hi Graham

 

Wicked - so I am I right in thinking that collimation is adjustable via the two spring loaded bolts that hold the mirror cell to the truss, the third point being a sort of hinge around which the adjustment can rotate?

Graham likes this

Share this post


Link to post
Share on other sites

Has anyone stepped forward to help you with advice on the figuring of your primary mirror Graham? (I think I have seen your thread in Astrobuysell).

The Bolton group, makers of Johns big bins, in his thread, have been down that road and may be more than likely to help you.

cheers!

Graham likes this

Share this post


Link to post
Share on other sites
3 hours ago, Bottletopburly said:

Was the chap i mentioned to you graham of any help?

 

Certainly was David thank you.

He gave me ES Reid's contact details.

 

Bottletopburly likes this

Share this post


Link to post
Share on other sites

It most certainly was, I had tried and tried to find his contact details. 

Bottletopburly likes this

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now