Jump to content

SkySurveyBanner.jpg.21855908fce40597655603b6c9af720d.jpg

OMC140 in hospital....


Recommended Posts

.... under the care of Es Reid TD (Telescope Doctor ;))

I’ve been increasingly frustrated by the performance of this scope so decided to get it sorted properly. It has given me some very nice views of Jupiter on occasion but in general has been completely outclassed by the Tak for planetary observing. The only area it has been superior has been for lower power DSOs where the aperture has counted on OCs and GCs. It would not take very high power, and given that is supposed to be its strength it is frustrating.

The secondary is fixed on these scopes but I’ve tried collimating the primary and whilst I had managed to get it looking ok when adjusting, it was not stable and the star shapes were never that great. The clunking noise made when turning the scope over indicating a loose primary, possibly amongst other things.

I had tried to take the scope apart myself, but both primary cell and corrector plate were jammed on even after taking all the bolts out, hence the trip to the hospital.

Es had to take a mallet to it to remove the primary cell :eek:, something I would not have been brave enough to do, and has indeed found a loose primary. The locking ring was missing its M4 screw so had worked loose over time. In addition, the corrector plate is not square to the tube.

Hopefully all will be sorted and I will have a scope that performs to its full potential back in my hands when I’m back from my holiday. I do not have room to take it anyway so it may as well have some TLC whilst I’m gone.

I shall report back when I get a chance to test it out.

Link to comment
Share on other sites

17 minutes ago, Mark at Beaufort said:

Stu it will be interesting how things improve after being sorted by Es Reid. Its good that there are professional individuals that we can trust when our scopes need special attention.

Yes Mark, I’m intrigued to know how these scopes perform when at their best. I made a ‘cat cooler’ so am confident that I was getting rid of tube currents, but given how sensitive these things are to collimation errors, I’m hopeful that there should be a decent improvement. It would be fab to be able to take a 5.5” ‘apo’ overseas with me at some point!

Link to comment
Share on other sites

26 minutes ago, Knighty2112 said:

Mallets and telescopes are normally best kept well separate from each other

Not always. This Tele Vue 100/540 needs a hammer to be centered:

http://r2.astro-foren.com/index.php/de/10-beitraege/02-ed-optiken-halb-apos-und-frauenhofer-systeme/721-b041b-televue-100-540-petzval-system-fuer-die-astro-fotografie-holzhammer-technik

I assume the 100/540 is an older Tele Vue design, I hope newer ones need a less barbaric method! Optics tested excellent after the adjustment, by the way, 0.95 Strehl, and white diffraction patterns, a true apo.

Link to comment
Share on other sites

5 minutes ago, Ben the Ignorant said:

Not always. This Tele Vue 100/540 needs a hammer to be centered:

http://r2.astro-foren.com/index.php/de/10-beitraege/02-ed-optiken-halb-apos-und-frauenhofer-systeme/721-b041b-televue-100-540-petzval-system-fuer-die-astro-fotografie-holzhammer-technik

I assume the 100/540 is an older Tele Vue design, I hope newer ones need a less barbaric method! Optics tested excellent after the adjustment, by the way, 0.95 Strehl, and white diffraction patterns, a true apo.

Yikes! 

Link to comment
Share on other sites

6 minutes ago, Ben the Ignorant said:

Not always. This Tele Vue 100/540 needs a hammer to be centered:

http://r2.astro-foren.com/index.php/de/10-beitraege/02-ed-optiken-halb-apos-und-frauenhofer-systeme/721-b041b-televue-100-540-petzval-system-fuer-die-astro-fotografie-holzhammer-technik

I assume the 100/540 is an older Tele Vue design, I hope newer ones need a less barbaric method! Optics tested excellent after the adjustment, by the way, 0.95 Strehl, and white diffraction patterns, a true apo.

Nope, I think they still use the same basic design. Had to do this with my Genesis 

Link to comment
Share on other sites

Good to know there's a decent TD about - you never know when one may be needed. Hopefully Stu, when your scope is back in A1 condition it will enable you to finally split Zeta Herculis?! How bad were the out-of-focus interference patterns before the doctor's appointment?

Chris

 

Link to comment
Share on other sites

I used to have an OMC 140 with early 'souped up' optics. Optically it was great but the focusser was absolute rubbish. I had it to bits a number of times to try and fix it with no joy. Sent it back to OO and all they did was put thicker grease on it!

When it wasn't annoying me it did give the best views of Saturn and εLyr I've ever had.

Link to comment
Share on other sites

19 minutes ago, chiltonstar said:

Good to know there's a decent TD about - you never know when one may be needed. Hopefully Stu, when your scope is back in A1 condition it will enable you to finally split Zeta Herculis?! How bad were the out-of-focus interference patterns before the doctor's appointment?

Chris

 

I'm hoping it will be good Chris but time will tell. I guess at least I will have the comfort of it being as good as it can be.

The defocused image didn't look that bad but it had a tendency to be slightly oval. I'm hoping the optics are basically sound, it was supposedly the higher spec optics but we will see what Es thinks!

Link to comment
Share on other sites

25 minutes ago, Paz said:

It will be interesting to hear what the doctor says, hope the scope gets well soon.

Latest comment is 'optics pretty good, round diffraction rings, no colour but just some coma caused by the tilted corrector'

Sounding promising :)

 

Link to comment
Share on other sites

5 hours ago, Mr Spock said:

I used to have an OMC 140 with early 'souped up' optics. Optically it was great but the focusser was absolute rubbish. I had it to bits a number of times to try and fix it with no joy. Sent it back to OO and all they did was put thicker grease on it!

When it wasn't annoying me it did give the best views of Saturn and εLyr I've ever had.

I bought said scope from Mr Spock, and had same joy/issues with it, when on form it was superb but when it did not want to play it was a cruel thing, and had my first big row with OOUK over this scope, hence why i will never have any dealings with them again

Link to comment
Share on other sites

I bought one of the purple tube versions shortly after they came out, and before the zygo testing was standard. I had very much the same issues and despite repeated returns to OO it never really performed. The diffraction patterns were indeed round and concentric but there was always a sharp spike on one side which I could never get rid of. It was easily beaten on planets by a Meade 127 Mak. I soldiered on for a couple of years with it but eventually gave it away  free on ABS to a school just out of sheer frustration. I'd be very interested to know if yours ever gets fixed properly.

RL

Link to comment
Share on other sites

Good luck with a fix there. I also had a purple tube OMC140. It was a love hate relationship too be fair. However I did have wonderful views of Saturn.

Rob

Link to comment
Share on other sites

17 minutes ago, Rob said:

Good luck with a fix there. I also had a purple tube OMC140. It was a love hate relationship too be fair. However I did have wonderful views of Saturn.

Rob

Thanks Rob. It’s funny how so many of us have had love hate relationships with these scopes. I had an OMC200 for a long time, and in hindsight it must have had a misaligned primary for much of that time, possibly even from new. I took it back to Orion Optics to be sorted but they fobbed me off with a tweak of the secondary. When I finally opened it up, it seems that a very similar thing had happened ie the locking ring was loose. I reseated the primary and all was well!

The positive is that even with the primary as it was, it could be collimated to an acceptable level and like you Rob, gave me some amazing views, probably my best ever of Saturn at x400 with a 13mm Ethos.

Link to comment
Share on other sites

I think the scope is ready to be discharged now ;)

Apparently the corrector plate was jammed in with some spacers and that was causing distortion, these have been removed and now it is just held correctly with the retaining ring.

Es says the optics are good quality and that it is performing well, so I'm looking forward to giving it a go! Mars here we come :)

Link to comment
Share on other sites

Great news that you’re scope is now sorted ??but reading between the lines here as a interested spectator, who has done a bit of searching etc .. on various forums it’s a bad show from Orion Optics UK surely?? 

We as amateur astronomers put all of our hard earned money into our hobby , so every penny counts, so when you pay a premium for a high end optical scope no matter what configuration, Mak , newt etc.. and you get a lemon! WHY? Obviously quality control is just not happening at this company, which i find quite sad , to hear people in the USA saying  how bad British scopes are ! And terrible customer service blaming the customer! again sad 

stuart 

Link to comment
Share on other sites

On 26/07/2018 at 21:35, stuy said:

Great news that you’re scope is now sorted ??but reading between the lines here as a interested spectator, who has done a bit of searching etc .. on various forums it’s a bad show from Orion Optics UK surely?? 

We as amateur astronomers put all of our hard earned money into our hobby , so every penny counts, so when you pay a premium for a high end optical scope no matter what configuration, Mak , newt etc.. and you get a lemon! WHY? Obviously quality control is just not happening at this company, which i find quite sad , to hear people in the USA saying  how bad British scopes are ! And terrible customer service blaming the customer! again sad 

stuart 

It is frustrating that the QC does not seem to be where it should be, this is the second OO Mak I’ve had where the primary came loose.

Anyway, on a more positive note, I received the scope back today. Fortunately I had packaged it well enough ‘to be dropped from the Tower’ as Es described it ;), and the same packaging brought it back safely to me after its discharge from hospital.

Amazingly the skies were mainly clear tonight, so I was able to pop it out for a quick session to try it out. The most obvious physical sign that things had changed was that the primary no longer clangs when handling the scope!

So, the million dollar question, was it worth it?.....

.....Absolutely yes :)

Defocused stars are now round, and the collimation looks pretty much bang on. I had some reasonable views of Jupiter although it was quite low, some nice festoons on show. The most noticeable thing though was the Galilean moons, round and lacking that fuzziness they used to show. Tiny disks, very nice.

Moving on to stars, the collimation improvement did really show when the seeing was good. The Double Double split at x83 and I also managed Pi Aquilae with a good clear split, at higher power obviously. When I tried Izar, the seeing in that area seemed worse and although it did split it was not a great image. Polaris on the other hand showed that lovely tiny secondary with a well controlled primary. That was at x83 again with the 24mm Panoptic.

Three more quick targets, M57, delightful view, clear little smoke ring even given the lack of full darkness. M13 was nice, showing good resolution and left me wondering just how good it would be under a dark sky. Finally NGC457 was fun as ever.

Overall I’m very pleased. It just feels like more light is being chucked into the airy disk so the stars are punchier, aswell as being nicer shapes. It will never be a frac, but I feel now that it is working to its full potential, and look forward to pointing it at Mars and Saturn very soon.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.