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Oil Spaced Triplet Refractor Oil Lifespan.

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#1 Plane_Guru

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Posted 12 July 2013 - 08:25 AM

Hello everyone,

I have another question for all you kind people regarding
Oil Spaced Triplet Refractors,specifically TEC Oil Spaced Triplet Refractors.

I would be very happy to hear your opinions on the subject of the lifespan of the "Oil"supposedly used in Oil Spaced Triplet Refractors..


I was informed that the "Oil" used in TEC Oil spaced Triplet Refractors has a lifespan longer than the Human Life....The "Oil"was referred to as a "Immersion Liquid".

I used to be of the belief that a Sillicon Oil was most likely utilised in Oil spaced Triplet Refractors because Sillicon Oil has has a very low vapour pressure.


I not long after reading about Sillicone Oil having a very low Vapour pressure then heard that Sillicone Oil Vapour Pressure (despite being very low), is not nearly low enough to be suitable for use in Oil Spaced Triplet Refractors,and that silicon Oil creeps and eventually attacks Coated front and back Glass outside surfaces in a Oil Spaced Triplet ...


Many Thanks.

#2 Eddgie

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Posted 12 July 2013 - 09:13 AM

This question comes up repeatedly.

While not a TEC, my oil spaced AP triplet is a few years away from its 30th birthday and seems to be perfectly fine.

It uses tape to hold the lenses in place.

#3 Scott99

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Posted 12 July 2013 - 10:42 AM

I think the oil will last virtually forever - but also consider that replacing the oil is not difficult - much easier than re-assembling an air-spaced lens, especially a triplet.

From what I've read, there are already a couple shops in Europe that can re-oil these lenses, and that's with TEC and AP still in business.

#4 Starhawk

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Posted 12 July 2013 - 10:59 AM

I've asked Roland about this directly- namely since I have been wondering about making a little future-life instruction card to put in with my AP130EDFGT when I am forced by circumstances I would put off indefinitely if it were up to me ultimately result in it being passed on.

The application in all of these is a very thin layer of fluid between lenses with a capillary sized air gap between them. The idea here is to have a material with an index of refraction closer to the glass so large reflections don't appear, even with bold use of high end optical coatings. In a way, this is similar to a cemented lens, but unlike with a cemented lens, if something goes wrong with the intermediate layer, it can be fixed. In practice, these lens sets are difficult to see when mounted as the only reflections are from the very first and very last surface, and those are with ultra-high transmission coatings.

The "Oil" is, in fact, oil. It is a vacuum compatible ultra-low vapor pressure oil chosen for its chemical stability and resistance to evaporation. The oil's primary use is in hard disk drive bearings, which should be the datum to allow someone to find equivalents in the distant future. Failing that, he suggested olive oil, or any clear oil with a similar index of refraction and a general resistance to going rancid.

The oiled lenses are designed to last indefinitely, and my understanding is either AP or TEC fix lens cells showing a bubble at no charge.

So, if you are nervous about getting a scope with oil spaced lenses, I suggest you shouldn't be- the image contrast is simply amazing.

-Rich

#5 Plane_Guru

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Posted 12 July 2013 - 02:38 PM

Hi,

Thank you for this info...knowing that "Oiled lenses" are designed to last indefinitely is reassuring.I ponder what Oil formulation TEC use..i ponder if TEC also use Oil's primarily used in Hard Disk Drive Bearings, like AP?

I would assume TEC's Oil Formulation is also Vacuum compatible ultra-low Vapour Pressure Oil.



I've asked Roland about this directly- namely since I have been wondering about making a little future-life instruction card to put in with my AP130EDFGT when I am forced by circumstances I would put off indefinitely if it were up to me ultimately result in it being passed on.

The application in all of these is a very thin layer of fluid between lenses with a capillary sized air gap between them. The idea here is to have a material with an index of refraction closer to the glass so large reflections don't appear, even with bold use of high end optical coatings. In a way, this is similar to a cemented lens, but unlike with a cemented lens, if something goes wrong with the intermediate layer, it can be fixed. In practice, these lens sets are difficult to see when mounted as the only reflections are from the very first and very last surface, and those are with ultra-high transmission coatings.

The "Oil" is, in fact, oil. It is a vacuum compatible ultra-low vapor pressure oil chosen for its chemical stability and resistance to evaporation. The oil's primary use is in hard disk drive bearings, which should be the datum to allow someone to find equivalents in the distant future. Failing that, he suggested olive oil, or any clear oil with a similar index of refraction and a general resistance to going rancid.

The oiled lenses are designed to last indefinitely, and my understanding is either AP or TEC fix lens cells showing a bubble at no charge.

So, if you are nervous about getting a scope with oil spaced lenses, I suggest you shouldn't be- the image contrast is simply amazing.

-Rich



#6 M13 Observer

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Posted 12 July 2013 - 07:17 PM

Hello everyone,

I was informed that the "Oil" used in TEC Oil spaced Triplet Refractors has a lifespan longer than the Human Life....The "Oil"was referred to as a "Immersion Liquid".

Many Thanks.


Telephone Yuri and ask him directly what kind of oil is used in your TEC telescope. You will then have the information from the only person you can actually speak with who can tell you.

#7 jrbarnett

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Posted 12 July 2013 - 10:54 PM

He says Mobil 1 with a coating-eating acidic additive. Good thing the oiled surfaces aren't coated, huh?

:grin:

- Jim

#8 Calypte

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Posted 13 July 2013 - 01:00 AM

and my understanding is either AP or TEC fix lens cells showing a bubble at no charge.

That's nice. What about after Roland and Yuri have retired? If you're interested, I can share a photo of a brand-new A-P 130GT with a discontinuity in the oil. Not sure I'd call it a "bubble." Roland repaired it, of course, but the risk of something like this happening to a scope several years from now would make me nervous. There's no chance I'll ever get an A-P (I'll be dead before my name bubbles to the top of the list), but I've looked fondly at the TEC 140.

#9 SteveC

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Posted 13 July 2013 - 11:23 PM

What's up with your preoccupation with TEC building materials?
Planning on going into the scope making biz?

#10 blueman

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Posted 14 July 2013 - 12:17 AM

and my understanding is either AP or TEC fix lens cells showing a bubble at no charge.

That's nice. What about after Roland and Yuri have retired? If you're interested, I can share a photo of a brand-new A-P 130GT with a discontinuity in the oil. Not sure I'd call it a "bubble." Roland repaired it, of course, but the risk of something like this happening to a scope several years from now would make me nervous. There's no chance I'll ever get an A-P (I'll be dead before my name bubbles to the top of the list), but I've looked fondly at the TEC 140.


Well, what if you buy an air spaced that no one will work on? Same kind of problem and you COULD be out of luck. However, it is easier to clean and re-oil a lens than to take many air spaced lenses apart and clear them.

If you don't like oil, then don't buy it!
Blueman

#11 gfeulner

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Posted 14 July 2013 - 01:29 PM

My 1986 AP oil spaced lens is as good today as the day I bought it. Gerry

#12 Rusty

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Posted 14 July 2013 - 06:04 PM

(as many of you know, I'm a recovering lube engineer. Oils can be refined or synthesized to have a VERY long life. The electric company's pole transformers have a specialty product, one not extremely processed, with an operating life in excess of 50 years.

The oil in objectives probably has a life in the 200-year plus range - processed or synthesized to be extraordinarily pure and homogeneous. Add to those characteristics the fact it is sealed from air, a very long service life is probable.

#13 Starhawk

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Posted 14 July 2013 - 07:18 PM

I expect you will find these either get a bubble early, like the AP 130 GT you're talking about, or take decades. And with something on the order of at least 1000 of his type of scope around, if there is any failure rate, there will be competent folks to work on them.

-Rich

#14 Plane_Guru

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Posted 15 July 2013 - 06:13 AM

What's up with your preoccupation with TEC building materials?
Planning on going into the scope making biz?



Hi SteveC,

Lol,no..I always ask in Depth Technical questions.I still have my name on the TEC list...I just NEED to be sure.I now know-about Oil Spaced Refractor "Oils".

I have recently purchased two great Officina Stellare " Falco 80" Guidescopes/Finderscopes for myself:

http://www.officinas....php?idProd2=45

I also currently own two Televue Starbeam Red Dot Finders.
I now own some nice accessories for Astronomy.


I am of the belief that AP's(Rolands) honesty when asked about the type of "Oil" (and the
"Oil" lifespan) in his Oil Spaced Refractors for Potential Customers is a virtue.
I am not going to worry about the Lifespan of "Oil" in Oil Spaced Refractors,anymore.





#15 JJK

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Posted 15 July 2013 - 10:26 AM

My 1986 AP oil spaced lens is as good today as the day I bought it. Gerry


Did it look good the first day? :grin:

#16 gfeulner

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Posted 15 July 2013 - 10:37 AM

Actually it was real purdy! What I meant is that the glass may not be as pristine today as back then but there are no bubbles or any indication of any oil problems. Gerry

#17 BillP

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Posted 15 July 2013 - 03:20 PM

I can share a photo of a brand-new A-P 130GT with a discontinuity in the oil. Not sure I'd call it a "bubble." Roland repaired it, of course, but the risk of something like this happening to a scope several years from now would make me nervous.


Longevity issues aside, while one does on occassion hear of an air bubble or similar in an oiled objective, one thing that can be said for certain that it is very much rarer to ever hear of an oil droplet between an air-spaced objective! Food for thought. :lol:

#18 Calypte

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Posted 15 July 2013 - 05:49 PM

I also currently own two Televue Starbeam Red Dot Finders.

Are these oil-spaced?

#19 PeterR280

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Posted 15 July 2013 - 07:05 PM

What happens if the seal between lenses leaks and you get condensation between air-spaced lenses?


Longevity issues aside, while one does on occassion hear of an air bubble or similar in an oiled objective, one thing that can be said for certain that it is very much rarer to ever hear of an oil droplet between an air-spaced objective! Food for thought. :lol: [/quote]

#20 Jeff B

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Posted 15 July 2013 - 10:27 PM

What happens if the seal between lenses leaks and you get condensation between air-spaced lenses?



They explode. :dabomb: :dabomb: :dabomb:

#21 jrbarnett

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Posted 15 July 2013 - 10:38 PM

True, but decentered and miscollimated air spaced systems are a fairly common topic in forums. :shrug: That's not really a problem with oiled objectives.

Regards,

Jim

#22 PeterR280

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Posted 15 July 2013 - 10:54 PM

Would you ever tell a girl you were trying to date that you were participating in a debate on the merits of oil-spaced and air-spaced refractors?

#23 jrbarnett

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Posted 16 July 2013 - 12:50 PM

Personally, I wouldn't date a girl that wouldn't wade right into the fray and state and defend her position eloquently and compellingly. Breeders are a dime a dozen. Equals, rare as hen's teeth. I prefer the latter. :winky:

- Jim






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