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A stream of "something" inside the OTA

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23 replies to this topic

#1 Michael Nugent

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Posted 17 May 2009 - 08:01 PM

Hi All,

As I was setting my scope up for viewing tonight I noticed that I have a stream of "something" inside the bottom of the OTA. Not sure if it is grease or oil but it is just a tad disconcerting . It does not appear to be runny but there is a bit of a sheen to it - cannot determine where it is coming from. I have read previous posts of folks who have taken off the front corrector plate and as a person who has been a little to timid to even install the Bob's knobs that I purchased, that seems a little daunting. I have always kept my scope in th down position when storing (as when it is shipped), covered with the heavy-duty Tele-gizmo cover in the garage. Any ideas of remedies, causes and is this severe enough that I should do something (as in taking of the corrector plate to clean it up)? :confused:

Below is a picture of the inner OTA - hopefully you can see the little stream of wetness.

Thanks and clear skies,

Mike

Attached Thumbnails

  • 3111264-InnerOTA.jpg


#2 bill w

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Posted 17 May 2009 - 11:39 PM

water?
repeated condensation?
think i somehow got some in my ota once
took the diagonal and adapter off, pointed the thing up
and a little trickle ran out

might leave the scope in a dry place with the diagonal etc removed and the end opened to allow evaporation
but a covering to keep dust out

#3 mikiek

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Posted 18 May 2009 - 12:59 AM

Nope it's the lube inside the tube breaking down and that's the lighter part of it. It is not uncommon. I have a runny spot on a fork arm from the same type of deal. Wierd thing is it started happening in the middle of winter. Not like the summer heat caused the separation.

I would consider getting a closer look inside. My tube had a huge glob of lube on the side right behind the mirror. It was not running like yours but I suspect it could have. As it was serving no purpose I removed it.

Check this forum about 6-9 months back. There were several posts with a similar condition.

BTW - I store my scope pointing down with a Telegizmo in the garage as well. Unless your garage gets up in the 100s during the day you're fine.

#4 Midnight Dan

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Posted 18 May 2009 - 06:16 AM

This seems to be a problem with SCTs stored aiming down. The grease runs down the baffle tube and ends up on the inside of the corrector. While Celestron ships the units facing towards the base, it's not necessarily facing down. The whole unit is on its side inside the box.

Someone in a previous post said they talked to Celestron who recommended storing it horizontally.

-Dan

#5 dtsmith

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Posted 18 May 2009 - 10:54 AM

Check out the end of the baffle. Does it appear to have some sort of liquid on it? There is a known issue with some of these scopes having the lubrication on the baffle tube separate, with the oily portion running down the baffle and dripping on the corrector. I've had it happen twice now. The first time, I shipped it back to Celestron for cleaning (and a repair for a totally unrelated electronics issue). Within a month or six weeks of getting the scope back, the corrector was streaked again. I cleaned that one up myself. I haven't had an issue since, but now I store the scope at a 45 degree angle so if it happens again, it will hopefully drip on the side of the tube and not glass. Taking the corrector off for cleaning seems daunting at first, but it is really easy to do, even without being super cautious.

#6 Rusty

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Posted 18 May 2009 - 11:23 PM

Like prior poster have mentioned, it's likely base stock from the grease used on the baffle tube. Lithium soap-based greases have a tendency to separate - meaning the base stock separates from the thickener, and takes its own course. Best to remove the corrector and clean with mineral spirits, then leave the OTA open for couple of days (OK to point the tube down).

If you want to totally cure the problem, point the OTA slightly up, extend the mirror all the way (focuser knob CCW), remove the snap ring at the end of the baffle tube (Carefully!), and slide the mirror off the tube, rotate it sideways, and extract through the notches on the front cap.

Then clean the baffle tube and the mirror mount tube with mineral spirits, re-lube with Super Lube General Purpose grease, and reassemble.

#7 mikiek

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Posted 19 May 2009 - 02:29 AM

Just be carefull with mineral spirits around painted surfaces - like the inside of the tube ;)

#8 davidpitre

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Posted 19 May 2009 - 07:29 AM

Mike,
Welcome to the lube running club.
Clean it off, and don't store it corrector down.
Don't bother calling Celestron.

#9 mikiek

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Posted 19 May 2009 - 11:58 AM

David - I think your reply may have been for someone else. I don't have the problem and I have been storing the scope face down for almost 2 years.

Hard to figure why some folks do have the problem and others don't :question:

#10 dtsmith

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Posted 19 May 2009 - 02:33 PM

Original poster is named Mike also.

#11 edl

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Posted 19 May 2009 - 07:09 PM

I had the same issue with my CPC925 six weeks ago. It happened after storing the scope pointing down for only one day, but in the sun. It was, however, under a Telegizmos cover which is supposed to be protective of UV rays and heat build up. The streak had not, thankfully, reach the corrector.
Anyway, I did contact Celestron and they did send me an RMA. After reading some previous posts on cloudynights regarding this issue, I decided to clean the inside of the tube rather risk shipping it back (even though it was still under warranty).
Since then I haven't had the issue re-appear, but I have stored the tube horizontal only. I suppose one day soon I'll re-grease.

Best,
Ed L.

#12 Michael Nugent

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Posted 19 May 2009 - 07:11 PM

Yep, that's me - Mike :grin:

Thanks for all the replies - I appreciate it. I guess I am going to first start parking my scope in a more horizontal (or 45ish degree) position. I imagine that sooner rather than later I will take the front corrector plate off, there are nice directions with pictures here. Is there any particular substance I should use to clean off the grease, and while I am at it, any particular product that I should use to wipe down the secondary mirror and front corrector glass plate?

Thanks and clear skies,

Mike

#13 davidpitre

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Posted 20 May 2009 - 05:44 PM

Is it indeed on your secondary as well?
That will be a bit more of a challenge to clean.

You can use windex on your corrector, but see the numerous threads on corrector cleaning before you begin. Seriously, you don't want to scratch it.

#14 Michael Nugent

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Posted 20 May 2009 - 09:02 PM

Hi,

No, it all appears to be on the inside bottom of the OTA. I also have taken the visual back off and looked inside and that area looks to be clean. The corrector plate has nothing on it but it just looks a tad dusty and I figured when I have it off, it probably is a good time to give it a bit of a cleaning. I will do a search on cleaning the corrector though, because as you said, I do NOT want to scratch it!

Clear skies,

Mike

#15 dtsmith

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Posted 20 May 2009 - 09:21 PM

Windex and Kleenex worked fine here.

#16 Midnight Dan

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Posted 21 May 2009 - 06:14 AM

While today's coatings are a lot tougher than those of yesteryear, I would still use a lot of care when cleaning your optics. Here's a link to Dr. Clay's cleaning system from the ArkSky observatory:

http://www.arksky.org/asoclean.htm

I use his technique and cleaning solutions and have had very good results. Many here on Cloudy Nights recommend it. Technique is as important as the solutions you use. I know some people, including Uncle Rod, say that using Windex directly will not cause a problem, but to err on the side of caution I'd use Dr. Clay's solutions. Just my opinion.

-Dan

#17 Michael Nugent

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Posted 21 May 2009 - 06:59 AM

Dan,

Thanks for the link. After reading Dr. Clay's discussion on cleaning I realize that, other than wiping the grease from the bottom of the OTA (anything special I need to use to do that?), I really only need to remove dust from the corrector as there are no streaks or caked on debris. So, I will follow his instructions on using a brush to lightly wipe away the dust (when I gather enough courage to take the front corrector off :p).

Thanks again and clear skies,

Mike

#18 brianb11213

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Posted 21 May 2009 - 07:06 AM

I will follow his instructions on using a brush to lightly wipe away the dust

A puff or two with a rocket (large capacity bulb) blower is probably all that's needed. A small amount of dust will have no effect on the optical performace.

#19 edl

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Posted 21 May 2009 - 06:14 PM

I use Dr. Clay's formula and it works great... the least amount of streaking of any cleaner I've encountered. When taking off the corrector I also wear surgical cotten gloves to minimize any accidental finger prints.
I cleaned up my tube oil streak with just a lightly damp paper towel, dabbed up the moisture with another dry one, and let air dry before putting the corrector back. There is still a faint mark where the streak used to be, but you need to look hard to find it.
Of course I was lucky as my optics were untouched by the grease.

Best,
Ed L.

#20 Doug Neal

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Posted 21 May 2009 - 07:28 PM

Well, thanks a lot guys....I had to go and look at mine...Now I'm a member of the streaked grease club (about 2" long). Seriously, I'm glad that I've read this post. I've kept my scope pointing down for about a year in my spare bedroom which stays at a comfortable temp, year round. So, it's not necessarily a hot weather "thing" as some of you mentioned.
The slide/pics were very informative for marking the spacers and removing the corrector. Someday soon I'll get the nerve to try this technique...
Best of luck to all the club members that do give it a go.......

Doug Neal

#21 Rusty

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Posted 21 May 2009 - 10:28 PM

Note that cautions on using mineral spirits are incorrect. Mineral spirits will not damage paint that's cured; it's one of the most benign yet effective products for the purpose. It does take many hours to completely evaporate, which is why I mentioned leaving the OTA open for a couple of days.

#22 hammerhead

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Posted 22 May 2009 - 07:31 AM

Just a thought... and I don't know if it matters any... but..

I have always stored my OTA horizontal. But even still, if the scope has been sitting unused for a month or so I will take a minute or two to run the focuser stop to stop several times. My thinking is that it helps to redistribute the grease and possibly mix it up a little to keep it from seperating and dripping. Now I don't even know if the focuser/baffle tube is where the offending grease is coming from, but so far I haven't had any dripping grease. Could also just be dumb luck though.

#23 Rusty

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Posted 23 May 2009 - 12:09 AM

I've had my mirror off the baffle tube twice; the first time (being a recovering lube engineer) I was appalled with what was there. The second time, after using Super Lube General Purpose Grease, I had none of those concerns (as expected). Now I don't worry about the orientation of my scope, in short- or long-term storage.

#24 rookie

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Posted 23 May 2009 - 10:09 AM

I also keep my telescope and my eyepieces in the house, in my dining room so it's not exposed to temperature extremes over long periods. We have so much humidity here, I think the a/c in the house helps reduce any growth of fungus on the coatings too.


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