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Old 06-06-2019, 04:31 PM
Stefan Buda
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OOUK 3" Wynne corrector autopsy

A couple of days ago I received Paul's troublesome corrector and we agreed to make public the findings of the autopsy, here on IIS.

The very first thing I wanted to do was to turn up a fixture on the lathe so that I could screw on the corrector and measure the external runout of the housing relative to the tread that is supposed to be concentric with the internals.

In order to measure the internal thread properly, I had to unscrew the retaining ring that keeps the internals from falling out.
Well, I had low expectations for the workmanship and I was not surprised to find that the retaining ring was so poorly made that it would be considered bad even on agricultural equipment. Someone just turned up a threaded pipe and then parted off 4mm wide rings without any attempt of chamfering the thread or further finishing cuts. The internal edges are manually and unevenly chamfered. The sides of the ring have the rough finish characteristic of parting off operations. Frankly this is butchery not even general engineering practice, not to mention optical equipment standards.
Anyway, I measured the thread to be M71.7 x 0.75 If you ask what the heck is that, I can't answer because I've never seen such a thread.
I did turn up a matching fixture and proceeded to measure the runout of the external cylindrical part. The end furthest from the jig had a runout of 0.12mm which is not good but not a disaster. However near the jig it exceeded the range of my dial indicator and had to use a coarser one which measured it to be 0.44mm That is very bad and I completely fail to understand how someone can produce something that bad. You don't need a dial indicator to see how bad it is spinning. So what was the culprit thinking?
Next I looked through the spinning corrector to find that everything - all the lens surfaces - were wobbling madly.

On the next episode we'll take a closer look at the internals.
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Old 06-06-2019, 05:04 PM
Wavytone
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Stefan I am not surprised... OOUK have prior form regarding appalling quality when it comes to exotic optics, starting with their maksutovs some years ago. Wouldn't touch anything from them with a bargepole.
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Old 06-06-2019, 05:28 PM
Ukastronomer (Jeremy)
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Stefan I am not surprised... OOUK have prior form regarding appalling quality when it comes to exotic optics, starting with their maksutovs some years ago. Wouldn't touch anything from them with a bargepole.
I bought a scope from Orion Optics years ago, an 8" "observatory class ???" reflector on Vixen mount. As a NEWBY then, I had problems with the focusser NOT reaching focus, the help I received was non existent, I was left feeling as if I were an inconvenience to them.

When I was looking to get back into astronomy 18 months ago the one place I refused to go to was Orion Optics

Their after sales service was terrible.

I would never ever use them again, the sale is only the first step, AFTER sales is also just as important and they were bordering on RUDE.

Eighteen months ago I decided to get back into Astronomy, I never even contacted them, They ended up losing £12,000 in sales and this year alone I have spent another £1200 they have not had, purchasing is on going, they will lose out on many more thousands and not just from me no business can afford that loss and I can not be the only one, perhaps just the only one they will KNOW about if they read this
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Last edited by Ukastronomer; 06-06-2019 at 05:44 PM.
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Old 07-06-2019, 06:32 PM
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Quote:
Originally Posted by Stefan Buda View Post
A couple of days ago I received Paul's troublesome corrector and we agreed to make public the findings of the autopsy, here on IIS.

The very first thing I wanted to do was to turn up a fixture on the lathe so that I could screw on the corrector and measure the external runout of the housing relative to the tread that is supposed to be concentric with the internals.

In order to measure the internal thread properly, I had to unscrew the retaining ring that keeps the internals from falling out.
Well, I had low expectations for the workmanship and I was not surprised to find that the retaining ring was so poorly made that it would be considered bad even on agricultural equipment. Someone just turned up a threaded pipe and then parted off 4mm wide rings without any attempt of chamfering the thread or further finishing cuts. The internal edges are manually and unevenly chamfered. The sides of the ring have the rough finish characteristic of parting off operations. Frankly this is butchery not even general engineering practice, not to mention optical equipment standards.
Anyway, I measured the thread to be M71.7 x 0.75 If you ask what the heck is that, I can't answer because I've never seen such a thread.
I did turn up a matching fixture and proceeded to measure the runout of the external cylindrical part. The end furthest from the jig had a runout of 0.12mm which is not good but not a disaster. However near the jig it exceeded the range of my dial indicator and had to use a coarser one which measured it to be 0.44mm That is very bad and I completely fail to understand how someone can produce something that bad. You don't need a dial indicator to see how bad it is spinning. So what was the culprit thinking?
Next I looked through the spinning corrector to find that everything - all the lens surfaces - were wobbling madly.

On the next episode we'll take a closer look at the internals.
Glad to see I was not totally losing my mind. I knew this piece of expensive crap was a wobbletronic device. I wonder what other interesting tit bits you will have for us Stefan. I hope OOUK take a look at this thread. I am sure someone will alert them to the thread being here.
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Old 07-06-2019, 07:41 PM
Ukastronomer (Jeremy)
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Yes

If they are any good they will respond professionally..................... ................ I bet not
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Old 07-06-2019, 07:49 PM
Stefan Buda
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Today I unscrewed the two retaining rings and all the internals came out as one stack, comprising of three lens groups and two cylindrical spacers. The lens in the middle is much smaller than the other two, so it has a ring around it to bring it up to the same diameter as all the other internals.
Interestingly, they used three pieces of sticky tape to hold the small lens in place, on the concave side, and the spacer on that side has a chamfer that contacts the edge of the lens - or more exactly the pieces of sticky tape. Maybe the sticky tape is meant to act like a cushion to protect the lens. In any case the edges of the lenses seem to be hand chamfered and not very even. The internals are a rather loose fit into the bore of the housing. I measured the parallelism of the two spacers and found the long one to be out by 0.2mm and the short one by 0.4mm - no comment. Also the ends of both spacers, where they make contact with the large lenses, are very rough, almost as if they were cut with a hacksaw. Is it a cushioning layer that has been painted on?
I'm reluctant to measure the wedge error of the lenses as there is a dander of scratching them. It may be possible to re-mount them in a self centring manner if the wedge errors are not too bad.
Next I turned another fixture so that I can hold the housing from the other end and see if the outside features were turned in one setup. Unfortunately I could not get it to run true. Probably the end is out of square and makes everything wobble when screwed into the fixture.
That was the autopsy. Any suggestions for the resurrection?
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Old 07-06-2019, 07:49 PM
croweater (Richard)
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Quote:
Originally Posted by Paul Haese View Post
Glad to see I was not totally losing my mind. I knew this piece of expensive crap was a wobbletronic device. I wonder what other interesting tit bits you will have for us Stefan. I hope OOUK take a look at this thread. I am sure someone will alert them to the thread being here.
I sincerely hope anyone contemplating buying OOUK also see this thread Paul so they don't have to go through what you have. Watching Stefans' work with interest as I'm sure many are. Thanks for bringing this to everyone's attention. Cheers, Richard
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Old 07-06-2019, 07:52 PM
Ukastronomer (Jeremy)
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but what was the actual scope ?
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Old 07-06-2019, 08:58 PM
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but what was the actual scope ?
ag12
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Old 07-06-2019, 10:13 PM
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Originally Posted by Stefan Buda View Post
Today I unscrewed the two retaining rings and all the internals came out as one stack, comprising of three lens groups and two cylindrical spacers. The lens in the middle is much smaller than the other two, so it has a ring around it to bring it up to the same diameter as all the other internals.
Interestingly, they used three pieces of sticky tape to hold the small lens in place, on the concave side, and the spacer on that side has a chamfer that contacts the edge of the lens - or more exactly the pieces of sticky tape. Maybe the sticky tape is meant to act like a cushion to protect the lens. In any case the edges of the lenses seem to be hand chamfered and not very even. The internals are a rather loose fit into the bore of the housing. I measured the parallelism of the two spacers and found the long one to be out by 0.2mm and the short one by 0.4mm - no comment. Also the ends of both spacers, where they make contact with the large lenses, are very rough, almost as if they were cut with a hacksaw. Is it a cushioning layer that has been painted on?
I'm reluctant to measure the wedge error of the lenses as there is a dander of scratching them. It may be possible to re-mount them in a self centring manner if the wedge errors are not too bad.
Next I turned another fixture so that I can hold the housing from the other end and see if the outside features were turned in one setup. Unfortunately I could not get it to run true. Probably the end is out of square and makes everything wobble when screwed into the fixture.
That was the autopsy. Any suggestions for the resurrection?
This is what I suspected all along and I wished it was not true. I suspected early on that the threads were not square due to the changing shapes of stars when the adapter was rotated to another position. With any luck you can find a solution to the problem.
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Old 07-06-2019, 10:35 PM
Ukastronomer (Jeremy)
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ag12
???? what's an ag12
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Old 07-06-2019, 11:05 PM
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???? what's an ag12
It's made by OOUK; the model is an AG12.
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Old 08-06-2019, 01:38 AM
Ukastronomer (Jeremy)
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It's made by OOUK; the model is an AG12.
So it is a Newtonian Astrographs
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Old 08-06-2019, 08:00 AM
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So it is a Newtonian Astrographs
Yes it is a Newtonian Astrograph.
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Old 09-06-2019, 08:59 PM
Stefan Buda
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Made some progress with the resurrection today.

After failing to get the housing running true in the second fixture, I took off the three jaw chuck with the fixture attached and put on the four jaw one with the first fixture so I could manipulate the housing until the barrel's OD was running true. Once I achieved that it became apparent that the thin end is oval by about 0.04 - not a major problem I guess, but it shows that the person that made it, didn't not know about internal stress in stock aluminium or didn't give a damn. Then I re-machined the big end, removing the minimum amount material, paying special attention to the inside of the lip that one of the lenses sits against. That lip had a shocking runout - I had to remove about half a millimetre from the inside face to get a nice continuous surface.
After this I swapped the chucks again hoping that this time the damn thing will run true in the second fixture, because the end has been trued up and the thread seemed concentric with the barrel. It did not. And that meant one thing: The butcher that cut the big thread at the end, did clock up that end but id did not worry about the fact that the other end was running out. So the thread was cut on a slight angle. I had to swap the chucks again. Went back to the four jaw one with the first fixture and re-cut the big thread. It was already a bit undersize so now it is even more so but it is straight. A loose thread should not cause a problem in this case. While I had the thing set up in this manner, I used a boring bar to open up the inside diameter until the eccentricity was gone. My boring bar was only long enough to go in about half the length of the housing. Once I swapped the chucks again and found that the housing was finally running true in the second fixture, I was able to complete the boring of the ID from the thin end, and also recut the short M82x1 thread. At this stage I also had to cut a new internal thread, which had to be a non standard M72.5x1 because I did not want to make the barrel any thinner.
Absolutely amazing that there were no two features on this part that were consistent with each other.
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Old 09-06-2019, 09:05 PM
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Stefan are you confident the lenses are any better quality than the metalwork ?

Reminds me of scopes assembled by a certain company whose approach to bolt sizes was to pick up anything lying on the floor and use that. No two the same on an entire OTA and mount.
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Old 09-06-2019, 09:51 PM
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The lenses actually look well made apart from the hand chamfering. I don't think OOUK made them in house. They probably just added their signature with the chamfering because they wanted to reduce the chance of chipping them during assembly. But I will investigate further.
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Old 10-06-2019, 01:55 PM
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Originally Posted by Stefan Buda View Post
Made some progress with the resurrection today.

After failing to get the housing running true in the second fixture, I took off the three jaw chuck with the fixture attached and put on the four jaw one with the first fixture so I could manipulate the housing until the barrel's OD was running true. Once I achieved that it became apparent that the thin end is oval by about 0.04 - not a major problem I guess, but it shows that the person that made it, didn't not know about internal stress in stock aluminium or didn't give a damn. Then I re-machined the big end, removing the minimum amount material, paying special attention to the inside of the lip that one of the lenses sits against. That lip had a shocking runout - I had to remove about half a millimetre from the inside face to get a nice continuous surface.
After this I swapped the chucks again hoping that this time the damn thing will run true in the second fixture, because the end has been trued up and the thread seemed concentric with the barrel. It did not. And that meant one thing: The butcher that cut the big thread at the end, did clock up that end but id did not worry about the fact that the other end was running out. So the thread was cut on a slight angle. I had to swap the chucks again. Went back to the four jaw one with the first fixture and re-cut the big thread. It was already a bit undersize so now it is even more so but it is straight. A loose thread should not cause a problem in this case. While I had the thing set up in this manner, I used a boring bar to open up the inside diameter until the eccentricity was gone. My boring bar was only long enough to go in about half the length of the housing. Once I swapped the chucks again and found that the housing was finally running true in the second fixture, I was able to complete the boring of the ID from the thin end, and also recut the short M82x1 thread. At this stage I also had to cut a new internal thread, which had to be a non standard M72.5x1 because I did not want to make the barrel any thinner.
Absolutely amazing that there were no two features on this part that were consistent with each other.
This is pretty much a word for word description made by a machinist friend here that took a look at the OOUK camera adapter. He found the same issues that one end did not match the other and nothing was true. Incredible that their machining is not at your level. I cannot understand why they would produce equipment like this and then charge huge sums of money for it. Caveat emptor I believe is relevant here. Please learn from my mistake.
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Old 11-06-2019, 06:19 PM
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Sorry guys, you will have to wait a bit longer for the next instalment, as I wound up in the Alfred hospital, on Monday morning. The tests are ongoing and hopefully it is nothing serious.
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Old 11-06-2019, 06:25 PM
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Sorry guys, you will have to wait a bit longer for the next instalment, as I wound up in the Alfred hospital, on Monday morning. The tests are ongoing and hopefully it is nothing serious.
Sorry to hear this Stefan, hope all is well. It’s a very interesting read.
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