Orion Optics UK

[ukskies]

Last year, as I was getting nearer to retirement age I decided that once I hit the 66 I would go down to part time working allowing some time to be spent on things I want to do. One of these things is making a telescope mirror, yes I'm a budding glass pusher.

I have managed in the last 6 months to purchase a couple of smaller mirror blanks from Terry at Vacuum Coatings, one Pyrex 8.75" and one Suprax near 200mm with a view to having a bash at it.

About 3 months ago I saw a project telescope for sale on UKABS, it was an old Orion Optics Europa 10" F4.8 1200mm FL from the 1990's with green trims on the (very) white tube, it also came with rolled tube rings and dovetail bar to match (green), the vendor wasn't too far from me but rather than put a price was asking for reasonable offers.

I left it for a few weeks undecided and finally decided to contact him. The mirrors were not in the best of condition as the scope had been standing unused in a shed and looked like they would need re-coating, I immediately thought if the price was low enough of these mirrors (prob Pyrex) were basically preformed  blanks for re-figuring. they are already ground and polished so it's going to be a lot easier than starting from scratch right? I went to view the scope as he was only asking £45 so I brought it home and put it in the garage. If you're reading this, Thanks again Lee.

I plan to build a Foucault tester and have all the materials to hand for this and most of the materials I need to build a powered turntable for the mirror.

There are some dents in the tube to address though it doesn't effect functionality and I have decided to stip, re-figure and re-coat the primary, either re-figure or replace the secondary and build my own Dob mount for this scope. I think it will make a very nice, lightweight 10" for a bit of general use and portable to some nearby dark sky locations.

I will probably do a thread on it just to amuse you all because, well I hate being the only one laughing at me!  🤣

Finally the reason for this thread.....  Well I've only gone and done it again!!! 🙈

Yes, another ad on UKABS that sat there for a couple of weeks, another OO reflector, this time a VX8L F6 and I've always fancied an 8" Dob. This one took a two hour drive but a quick look (well that's all you get isn't it?) showed it to be in almost unmarked condition. The focusser was a 2" single speed affair and felt horrible and a look down the tube showed a nice reflective primary., it also came with nice white rolled rings and a dovetail and  I paid the vendor 90 quid for this nicer , newer scope.

I decided on arrival home to inspect the glass and the mirrors were filthy and i stripped the focusser and adjusted the grub screws so that it runs smoothly.  The mirror is labelled march 2004 and I have today attempted to clean it but there are many stubborn particles that simply won't give up their grip and any further work is almost certainly going to damage the coatings. The mirror is also looking like another candidate for future re-coating and may also get re-figured too however I had kind of hoped to give this scope a bit of light first and star test it. I still think this is possible but for now the primary is sitting in a sealed container as I am planning to upgrade the mirror cell to a 9 pointer  and to relocate the poorly positioned collimation bolts and actually re-build the cell accurately as intended. This will centre the mirror in the tube too as it sits slightly off centre due to the cell halves not quite lining up.

Anyway as I'm prepared to tinker, desired to have a go at glass pushing and being quite handy and practical I believe that these used OO scopes are exceptional value as projects for re-building and I also think it's nice in this modern throw away world to rescue something and breathe new life into it.

[ukskies]

A few pics of the 8L.

[Craney]

Just looks at those secondary vanes !!!    

What type of diffraction pattern will those give ??

[ukskies]

8 minutes ago, Craney said:

Just looks at those secondary vanes !!!    

What type of diffraction pattern will those give ??

I have no idea but as they are curved they may not be too bad. One thing tho that secondary wont move a thou in any direction, it's very well located.

[StarryEyed]

1 hour ago, ukskies said:

...... I also think it's nice in this modern throw away world to rescue something and breathe new life into it.

With you all the way. 

[davidc135]

Looking forward to following progress.   David

[Robindonne]

2 hours ago, Craney said:

Just looks at those secondary vanes !!!    

What type of diffraction pattern will those give ??

The idea is that spikes are canceled out.  In reality they show weaker, more spread, but less visible spikes

[ukskies]

6 hours ago, Robindonne said:

The idea is that spikes are canceled out.  In reality they show weaker, more spread, but less visible spikes

Yes, that's how I understand it, the diffraction is spread (diffused?) over more of the image but much weaker and thus less noticeable than the more conventional 4 vane spiders produce, proof of the pudding is however yet to be sampled.

[ukskies]

8 hours ago, davidc135 said:

Looking forward to following progress.   David

Thanks David. I should probably start a new thread for the rebuild in the DIY Astronomer forum?

Edited June 3, 2022 by ukskies

[faulksy]

37 minutes ago, ukskies said:

Yes, that's how I understand it, the diffraction is spread (diffused?) over more of the image but much weaker and thus less noticeable than the more conventional 4 vane spiders produce, proof of the pudding is however yet to be sampled.

generally curved vanes show very little defraction spikes

some ace little gems you bought there

[ukskies]

13 minutes ago, faulksy said:

generally curved vanes show very little defraction spikes

some ace little gems you bought there

Thanks Mike, yes I'm very happy with both purchases, I'm out £135 for the two scopes atm tho more will have to be spent to get them up and running it's still a no brainer compared to the cost of blanks and starting from scratch.

I see you are soon to be a close neighbour?

[faulksy]

4 minutes ago, ukskies said:

Thanks Mike, yes I'm very happy with both purchases, I'm out £135 for the two scopes atm tho more will have to be spent to get them up and running it's still a no brainer compared to the cost of blanks and starting from scratch.

I see you are soon to be a close neighbour?

yes you are correct garry (neighbour) cant wait mate. mag 21 59 from my garden 🤣

[Stu]

11 hours ago, Craney said:

Just looks at those secondary vanes !!!    

What type of diffraction pattern will those give ??

They are designed to cancel out the diffraction spikes; any curved vane that goes through multiples of 180 degrees will do this. It doesn’t get rid of diffraction, but smears it around through 360 degrees so it is less noticeable. I’ve always wanted to try one of these in my 8” f8.

[ukskies]

4 hours ago, Stu said:

They are designed to cancel out the diffraction spikes; any curved vane that goes through multiples of 180 degrees will do this. It doesn’t get rid of diffraction, but smears it around through 360 degrees so it is less noticeable. I’ve always wanted to try one of these in my 8” f8.

I've always wanted to try an 8"f8.😉

Great planetary newt with a small central obstruction. 

[ukskies]

I've just taken a few more pics. This is the very nice tube cradle for the 8L.

[ukskies]

Some pics of the 250. I don't think it's ever done much work, there's hardly any marks on the dovetail. Note the collimation knobs! 🤣

[Carbon Brush]

Thank you Gary for posting.
Along with others I look forward to hearing how the projects progress.
Wing nuts for collimation and rolled rings remind me of my new 2003 OO 8" newt.
Though by 2003 they had gone for the modern black look.
I also bought (long story) a used 10" F4.8.
Both had good mirrors.

I'm sure you know this already, but even awful looking mirrors can give good results.
What I'm getting at is don't rush out for recoat.

Enjoy the projects, David.
 

[faulksy]

5 hours ago, Stu said:

They are designed to cancel out the diffraction spikes; any curved vane that goes through multiples of 180 degrees will do this. It doesn’t get rid of diffraction, but smears it around through 360 degrees so it is less noticeable. I’ve always wanted to try one of these in my 8” f8.

im sure john had a dob with this type of spider stu.

he might mention it

[ukskies]

24 minutes ago, Carbon Brush said:

Thank you Gary for posting.
Along with others I look forward to hearing how the projects progress.
Wing nuts for collimation and rolled rings remind me of my new 2003 OO 8" newt.
Though by 2003 they had gone for the modern black look.
I also bought (long story) a used 10" F4.8.
Both had good mirrors.

I'm sure you know this already, but even awful looking mirrors can give good results.
What I'm getting at is don't rush out for recoat.

Enjoy the projects, David.
 

Hi David, thanks for that, there's no rush to re-coat, the 8" mirrors will see light before I do anything, The 10" will probably also see light as is but only to help assess the mirrors. this will be my first attempt at re-figuring and I can't wait. Due to current circumstances this is still a few months away tho so don't get too excited. 

My problems are mainly logistics in the garage/ workshop which has become a storeroom for a lot of stuff left over from when we downsized into this current home, it needs sorting and then I'll get my workshop back complete with my newly built bench for optics testing.

Other jobs will be done in the meantime during the clear out to upgrade the 8" a little.

[davidc135]

1 hour ago, ukskies said:

Some pics of the 250. I don't think it's ever done much work, there's hardly any marks on the dovetail. Note the collimation knobs! 🤣

 

 

 

But I wonder what the diffraction effects of this beam is?  David

[NGC 1502]

18 minutes ago, davidc135 said:

But I wonder what the diffraction effects of this beam is?  David

Not ideal, ok for the faint stuff, not good for bright planets.  But if you’re into DIY easy fix compared to mirror making😊

On the other hand, that thick bar tends to hold collimation well👍

Edited June 3, 2022 by NGC 1502
Extra info

[Stu]

37 minutes ago, davidc135 said:

But I wonder what the diffraction effects of this beam is?  David

That would just give two diffraction spikes, probably quite bright due to the thickness of the support.

[Stu]

1 hour ago, faulksy said:

im sure john had a dob with this type of spider stu.

he might mention it

Indeed, John has often posted about the curved vane slides on his 12”. I suspect it makes splitting doubles easier as you can’t lose the secondary star behind a diffraction spike.

In theory, a single 180 degree curved vane support would be shorter than the figure of 8 design and therefore have less overall diffraction but it may not be that noticeable a difference.

[Stu]

2 hours ago, ukskies said:

I've always wanted to try an 8"f8.😉

Great planetary newt with a small central obstruction. 

Yep, it’s a cracking scope. Amazing performance for not a lot of money compared with the alternatives.

[ukskies]

Hi guys, yes the thick spider vanes will almost certainly be an issue and they are on the hit list possibly on both scopes.

They are not near the top of the list tho as getting the scopes up and running is the first objective and unless things change the little 8" will be first up.