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Oil spaced APO's can leak if improperly stored or maintained

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#1 dr.who

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Posted 14 November 2018 - 11:48 PM

I do not want to point fingers. I do not want this to turn into a flame war. So if you feel strongly enough on the subject to react in anger please step back from the keyboard and take a moment. I am not naming the vendor that made this scope. I am not naming the vendor who made the other scopes I have seen this problem with. It doesn't matter who made it. What matters is this can happen with oil spaced triplets. Once is a fluke, twice is a coincidence, three or more times and something is going on...

 

... This will be the third one of these I have personally seen develop this problem. So far it has been due to storage for long periods (1+ year) in a horizontal position. I am guessing the two ways to prevent this are:

 

1. To use the scope regularly and often

2. rotate the position that it is stored or perhaps store it vertically(?)

 

In each case the vendor has made things right for the owner. Unfortunately there was still a cost involved. And for larger apertures the shipping price can become prohibitive by itself regardless of the cost for the vendor to perform the repairs. And in all three cases these were not 20+ year old scopes.  

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  • oil leak in an APO.jpg

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#2 TG

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Posted 15 November 2018 - 01:03 AM

I've had an AP triplet leak when sent by air. Never had any problems in storage on the ground.

#3 agmoonsolns

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Posted 15 November 2018 - 02:54 AM

I had an AP triplet leak on me too, but all I had to do was send it back and Roland made everything right. I think he upgraded the cell for free too so it wouldn't happen again. Seemed like it performed even better once returned too. I don't think this is a problem with the newer AP lenses, but I have been hearing about it happening with the older lenses with increasing frequency. If you have any worries, just call AP. They can tell you about your lens and will upgrade your cell/oil if needed. The the thing is, if you upgrade your cell, they might change out the oil too and I think they use a better oil now. Don't quote me on that though as it has been a very long time. I just know they totally stand behind their products.

 

Fun fact, the very first AP used vegetable oil. Now, it's super expensive stuff with specialized indexes of refraction. The oil is actually part of the lens design. In the old days, the oil was held in place with special tape. The reason they leak with age is the oil starts to dissolve the adhesive in the tape. It takes many years, but it happens eventually. 


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#4 junomike

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Posted 15 November 2018 - 04:04 AM

That's too bad, however I prevent leaks by using a 3rd method.......Air Spaced Objectives.

Hopefully the repair will only cost you shipping.


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#5 Erik Bakker

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Posted 15 November 2018 - 05:23 AM

My personal experience: Oil spaced APO's can leak.


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#6 bobhen

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Posted 15 November 2018 - 08:16 AM

I owned 2, AP, 6-inch oil-spaced triplets for 22-years. The scopes were used in temperatures ranging from below freezing to above 80-degrees with no leaks. 

 

Oil can leak. Air-spaced triples need complicated cells, lens elements can become decentered and dirt or fungus can develop between the elements.

 

Nothing is perfect. But problems are rare. 

 

Bob


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#7 Fomalhaut

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Posted 15 November 2018 - 08:36 AM

My personal experience: Oil spaced APO's can leak.


I confirm having seen this with my own eyes. (The scope was an AP 6-incher.)

Edited by Fomalhaut, 15 November 2018 - 08:37 AM.


#8 crixt

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Posted 15 November 2018 - 08:42 AM

This is why I would not buy an oiled scope as my “forever” scope. Who is going to fix it many, many years later when the maker might not be ariund?  Hopefully I’ll get a second run of the AP Stowaway. I like that it is air spaced. Would be nice to have a good place to get any brand of used scopes serviced locally. 


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#9 elwaine

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Posted 15 November 2018 - 01:10 PM

This is why I would not buy an oiled scope as my “forever” scope. 

You youngsters are funny... worrying about your "forever" scopes leaking oil. First off, Nothing lasts forever. Second, at my age I'm much more concerned about me leaking oil than any of my scopes!

 

 

By the way, and just out of curiosity, how many of you have sold or traded your "forever" scopes long before forever came?


Edited by elwaine, 15 November 2018 - 01:12 PM.

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#10 dscarpa

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Posted 15 November 2018 - 01:42 PM

 I suspect OPT could do the repair if the manufacturer were to close. When my WO ZS110 took a tumble after the EZTouch came apart they cleaned it up and checked  collimation. They also put a new dovetail on my IM715D mak and made the focuser work a lot better.  David


Edited by dscarpa, 15 November 2018 - 01:51 PM.


#11 BillP

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Posted 15 November 2018 - 01:53 PM

Oil leaking over time is always an additional risk.  There certainly are enough examples of posts here and elsewhere of leaks developing in the various oiled Apos.  What is interesting here is that it seems that storing the scope in a fixed horizontal position for multiple years might increase the risk of a leak developing at the lower end of the objective.  I know of more than one case of this happening so not a one-off issue.  As long as the scope is actively used this would of course not be an issue.  Long term storage though seems advisable to store vertically.  No reason IMO for anyone to get defensive relative to oiled optics...actually good info to know for lower risk storage of oiled designs.

 

Thanks for the post waytogo.gif


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#12 Paul G

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Posted 15 November 2018 - 02:20 PM

Hmm... I have a half dozen oiled objective scopes, store them horizontally, most for over twenty years, no leakage.


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#13 Heywood

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Posted 15 November 2018 - 02:33 PM

I had an AP 130GT circa 2011 that, upon arrival, had an oil "problem," but I don't know that one would call it a "leak."  During shipment to me from AP, the 130's oil-spaced lenses came apart ever so slightly, resulting in a visible problem with the triplet lens.  I don't know how to describe it.  Anyway, AP instructed me to return the lens to them, which I did, and Roland C. repaired the lens and promptly returned it to me.  The experience did not turn me off oil-spaced lenses.

 

Heywood


Edited by Heywood, 15 November 2018 - 02:36 PM.

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#14 BillP

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Posted 15 November 2018 - 03:06 PM

Hmm... I have a half dozen oiled objective scopes, store them horizontally, most for over twenty years, no leakage.

 

Really!  You have 6 Apos you've not used for 20 years!!!!  OMG why?????????????  foreheadslap.gif  What are the storage environment conditions???? hmm.gif


Edited by BillP, 15 November 2018 - 03:18 PM.

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#15 agmoonsolns

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Posted 15 November 2018 - 03:19 PM

There are a HUGE number of AP scopes out there and it's a well-loved company. I am pretty sure when Roland goes to grinding lenses in the sky, they will have sold the business (designs, patents, recipe for the secret sauce, etc.) to an individual or company that is every bit as passionate about perfect optics and amazing customer support as he has been. 

 

Kind of like Questar continuing on after Braymer passed away, AP will continue on too for a very long time. There are some companies that achieve a very special kind of immortality and status as legend and AP is one of them. I am pretty sure there will be a company and people around to service AP scopes far beyond your own lifetime. 


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#16 R_Huntzberry

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Posted 15 November 2018 - 05:05 PM

Hi All,

 

This seems like a relevant thread to post this comment/question.

 

I've owned four oil spaced triplets over the years, a TEC 140ED, TEC 160ED, AP 155EDF and a CFF185. None of which developed any oil leakage while they were in my possession.

My question is this, has lens cell design for oil spaced triplets evolved over time or is it a relatively standardized cell configuration? Does everyone use Kapton tape? Do larger oil spaced lenses require a different cell arrangement than small lenses?

 

My reason for asking is I recently cleaned my CFF185 lens and I noticed something I don't recall ever seeing on any of my other oil spaced lens cells. I know it wasn't on my TECs and I'm fairly certain it wasn't on my AP 155 either.

There are 6 sets of 3 screws equally spaced around the perimeter of the cell, just as you would see in a air spaced objective for lens centering adjustments.

Wouldn't these screws pierce the Kapton tape (or whatever is used to seal the edge of the lens)? Maybe it has to do with the size & weight of a large oil spaced lens?

I've been mulling this over in the back of my mind for the past several days when up popped a thread on leaking oil spaced triplets.

 

Best regards,

 

Richard

 

 

Here's a few pictures of the setscrews:

 

CFF 185 Lens Cell_01.JPG

 

 

 

 

 

 

 



#17 R_Huntzberry

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Posted 15 November 2018 - 05:06 PM

CFF 185 Lens Cell_02.JPG



#18 Alan French

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Posted 15 November 2018 - 05:09 PM

It is hard to imagine, if the surfaces match and the oil layer is a few microns thick, there could be an actual leak. The capillary action holding the oil in place is far stronger than gravity trying to pull it down. (No real need to rotate the tube occasionally.) 

 

There have clearly been some problems with a few oiled lenses, but, if the curves match properly and the oil layer is a few microns thick, I doubt they are from actual leakage.

 

Evaporation would be a concern, but I understand special oil developed for spacecraft with a very low vapor pressure is the usual choice.

 

I have no direct experience with any problem oiled lenses, so I will not give the various possible causes I've heard over the years additional exposure. 

 

The only lens I have seen with a problem was a 5-inch, and it was essentially at the dawn of the modern apochromatic age. 

 

Clear skies, Alan


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#19 gnowellsct

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Posted 15 November 2018 - 05:41 PM

There are a large number of TEC 140 out there...oil leaks don't seem to be an issue.

Not sure it's a problem that would apply to all makes and models.

I definitely incurred costs getting the mold cleaned out of my air spaced doublet.

Time will tell I guess.

GN
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#20 Howard Gao

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Posted 15 November 2018 - 06:27 PM

Now I feel lucky for my AP 130GT...

What about APQ? I believe most owners are not using them and have been storing them horizontally for years.

#21 agmoonsolns

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Posted 15 November 2018 - 06:34 PM

The APQ is a totally different animal with a totally different system. The cell is built like the proverbial German tank. I haven't heard of a single APQ of any size have any problems (other than price).


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#22 Howard Gao

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Posted 15 November 2018 - 07:19 PM

I have seen the glass in the Nikon f/12 ED turning images increasingly yellow with time (can be seen when observing the moon, it takes on a slight, but observable yellowish tint). At first, I thought there was smoke or something in the air causing the color, but then I pulled out my Takahashi and it didn't have any yellow. Then I wondered about the coatings, but they looked fine. I went to great lengths researching this and eventually had Rodger of RVR Optical (imported and sold the Nikon telescopes and equipment back in the good old days). He spoke with Nikon and was told it was a characteristic of the glass. This is why Nikon no longer uses this glass and why you can't go out and buy a new Nikon f/12 ED refractor. The interesting part is, of the two I have seen, one demonstrated this effect (quite pronounced), but the other only had the slightest hint of yellow (might even have been my imagination). So, my guess is, it depends on the batch. If you have access to one of these, go out and observe the moon and compare it with a scope that shows the moon as a brilliant white (like a TSA or a good triplet). Let me know if you see any yellow in comparison. It will be like the Nikon has a very faint yellow filter that the triplet does not. You must compare side by side with a scope of the same aperture as I have seen owners think of this as an effect of the smaller aperture. When doing this, several owners have reported a very definite faint yellow tint absent in the 4" triplet.

I just got it this year so haven’t done many sessions yet. I did observe the moon and the color was quite neutral. I don’t think Nikon discontinued refractors because of glass problem. It was because their price was too high can can’t compete with other brands in the market. It was a well known fact.

Let’s not hijack this topic though. lol.gif


Edited by Howard Gao, 15 November 2018 - 07:22 PM.


#23 barbie

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Posted 15 November 2018 - 07:39 PM

I had an astro-physics 5" F12 oil spaced triplet that I bought from a friend who in turn had it for more than 20 years and neither he nor I had any problems with oil leakage. The person I sold it to 12 years ago hasn't had any problems either.



#24 crixt

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Posted 15 November 2018 - 07:42 PM

There are a large number of TEC 140 out there...oil leaks don't seem to be an issue.

Not sure it's a problem that would apply to all makes and models.

I definitely incurred costs getting the mold cleaned out of my air spaced doublet.

Time will tell I guess.

GN

This is a good point. Every system has issues.  I do get that.  It’s not that Roland, etc., won’t fix any problems that pop up.  They have excellent reputations.  Heck, I’m in line for a Stowaway.  I’d take an AP or TEC in a second.  And it’s not that the problems are widespread or even likely to happen. But, when it does happen, as it has for some folks who post here, what do you do?  Many years down the line, I feel that an air spaced lens would be easier to service. Maybe I am wrong. I don’t know of any third parties that service air spaced triplets properly right now. I see every now and then someone mention they can be serviced, but I never see a hard and fast, “contact this person or company and they can service your scope properly”. It’s usually the scope maker. So if I am gong to go premium, I kind of want that security, at least in my own mind, that I can get it fixed down the line if need be. By then, technology may have developed enough that my AP is basically nostalgia of some bygone era. But dang, I want it cleaned and looking up. Not leaked, or molded...but ready to go. If I were consolidated in my hobbies I guess it wouldn’t be a concern. But I’m spread thin. Married, 2 kids...I like scoping, fishing, shooting, boating, reef tanking, collecting vinyl and dj-ing, VR, brewing beer.  Lots of stuff besides this. In all of those hobbies, besides the brewing, I have zero chance of having the “best”. Astronomy is pretty unique in that I have a shot at actually having “the best”...or at least close. The rest of my hobbies?  Good luck. So air spaced for me. At least for now. If I had the cash, or the focus, then everything is on the table. 

 

My only edit:  I did not know that the underlined word was a bad word on this site. I edited this so folks didn’t think I said another prominent 4 letter word. LOL. 


Edited by crixt, 15 November 2018 - 07:46 PM.


#25 daquad

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Posted 15 November 2018 - 07:49 PM

Hmm... I have a half dozen oiled objective scopes, store them horizontally, most for over twenty years, no leakage.

I owned an AP Starfire 6" f/9 oiled triplet for more than 20 years.  Never had a leakage problem.

 

Dom Q.




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