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Equipment Discussions >> Eyepieces

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Darren Drake
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Reged: 10/09/02

Loc: Chicagoland
Comprehensive list of "Do Not Disassemble" eps
      #5705654 - 02/28/13 04:10 PM

After the most recent incident with the 24mm Status I would like to see someone put together a list of all the eyepieces that WILL fall totally apart if disassembled. That is they have no protective retaining rings at all to prevent certain disaster. I know I could have used this info when I once unscrewed a TV 55mm Plossl. Can anyone help on this??

Edited by Darren Drake (02/28/13 04:11 PM)


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Scott in NCModerator
Mad Hatter
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Reged: 03/05/05

Loc: NC
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: Darren Drake]
      #5705707 - 02/28/13 04:43 PM

I'm pretty sure that all of the Televue Wide Fields and Panoptics fall into this category, but don't know any others off the top of my head.

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hfjacinto
I think he's got it!
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Reged: 01/12/09

Loc: Land of clouds and LP
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: Scott in NC]
      #5705719 - 02/28/13 04:47 PM

I myself won't disassemble any EP. Well maybe a ball EP I will take apart.

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csrlice12
Postmaster
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Reged: 05/22/12

Loc: Denver, CO
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: hfjacinto]
      #5706097 - 02/28/13 07:56 PM

Yup, that's what they make factory reps and scope stores for.....

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NeilMac
Carpal Tunnel


Reged: 09/25/10

Loc: MedHat, AB, Canada
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: csrlice12]
      #5706363 - 02/28/13 10:54 PM

Why would you, are they loose enough for dust to go in?
I unscrew the silver base so I can get a brush to the under glass, thats it.


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Jaimo!
Pooh-Bah
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Reged: 10/11/07

Loc: Exit 135 / 40° North
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: NeilMac]
      #5706401 - 02/28/13 11:25 PM

Quote:

Why would you, are they loose enough for dust to go in?
I unscrew the silver base so I can get a brush to the under glass, thats it.




You have to see what's inside...?





Jaimo!

Ugh! I'm going to have to re-shoot the UO photo, it's terrible...


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Jon Isaacs
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: Scott in NC]
      #5706837 - 03/01/13 09:33 AM

Quote:

I'm pretty sure that all of the Televue Wide Fields and Panoptics fall into this category, but don't know any others off the top of my head.




The 24mm TV Widefield does not have a retaining ring, the 15mm does. My 32mm probably does not but it is too tight to get apart.

Given the history of their design, it should be no surprise that the 24mm Meade Series 5000 SWA does not have a retaining ring but the 16mm does.

Jon Isaacs


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csrlice12
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Reged: 05/22/12

Loc: Denver, CO
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: Jon Isaacs]
      #5706866 - 03/01/13 09:47 AM

Unscew the old T1s and it's glass puzzle time.....

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Traveler
Pooh-Bah


Reged: 08/19/07

Loc: The Netherlands
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: csrlice12]
      #5706904 - 03/01/13 10:04 AM

Don't disassemble a Baader Hyperion Clickstop Zoom Mark II or Mark III...

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csrlice12
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Reged: 05/22/12

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Re: Comprehensive list of "Do Not Disassemble" eps new [Re: Traveler]
      #5706937 - 03/01/13 10:22 AM

Easier Listing of eyepieces you shouldn't disassemble:

1. All


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Scott in NCModerator
Mad Hatter
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Reged: 03/05/05

Loc: NC
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: csrlice12]
      #5706945 - 03/01/13 10:27 AM

Quote:

Easier Listing of eyepieces you shouldn't disassemble:

1. All




I like that one!


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hfjacinto
I think he's got it!
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Reged: 01/12/09

Loc: Land of clouds and LP
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: Scott in NC]
      #5706952 - 03/01/13 10:29 AM

Quote:

Quote:

Easier Listing of eyepieces you shouldn't disassemble:

1. All




I like that one!




+1


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FirstSight
Duke of Deneb
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Reged: 12/26/05

Loc: Raleigh, NC
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: hfjacinto]
      #5707043 - 03/01/13 11:45 AM

The Nagler T5s and T6s CAN be safely unscrewed in half at their "waist" (both upper and lower lens assemblies are firmly held in place by retaining rings). Beyond that, you may be heading into dense briar-choked weeds trying to disassemble them further.

The ONLY reason to consider unscrewing a T5 or T6 Nagler at its waist is if condensation gets trapped and persists on either the lower lens surface of the top half or the upper lens surface of the bottom half. The main risk you take exposing these surfaces is inadvertent introduction of dust, in which case...um, you have to open it again to clean it out.

It *might* be possible to similarly do this with the T4s, but I've never tried it, and I simply have no idea whether such is also possible with the Ethos. However, prudence wins out handily over curiosity in both cases, and I have no intention to consider any experiments to find out, absent some truly compelling reason (and in the case of Ethos, would probably bite the bullet to send it to Televue and pay the cleaning service fee).


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Darren Drake
Carpal Tunnel
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Reged: 10/09/02

Loc: Chicagoland
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: FirstSight]
      #5707056 - 03/01/13 12:03 PM

There is a simple way to know if you're about to get into trouble if you start unscrewing an eyepiece. If after a bit of initial unscrewing you shake the eyepiece and hear some internal rattleing going on that's your big clue to stop and retighten or continue at your own risk as there are almost certainly no retaining rings in place to avoid possible disaster.

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csrlice12
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Reged: 05/22/12

Loc: Denver, CO
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: Darren Drake]
      #5707151 - 03/01/13 01:08 PM

Having the lenses fall into you lap is a really good indication you unscrewed it too far........appears we can easily add the Orion Stratus to the list.....

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Starman81
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Reged: 03/06/08

Loc: Metro Detroit, MI, USA
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: csrlice12]
      #5707382 - 03/01/13 03:35 PM

TV Plossl 32mm as well. Lenses did fall out but no damage and it was easy to put back together and an educational experience. I do take it apart to clean it when internal dust accumulates though...

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FirstSight
Duke of Deneb
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Reged: 12/26/05

Loc: Raleigh, NC
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: Starman81]
      #5707754 - 03/01/13 08:29 PM

One problem with disassembling the internal lenses in an eyepiece is that in additon to the one correct order and orientation of lenses, there are often several other ways to assemble the lenses together which also produce a plausibly acceptable image on-axis, but only indicate the likely incorrectness of ordering by the inferior performance of the outer half of the radius. I once owned a Meade 5000 series-60 6.5mm eyepiece which, during attempted cleaning of the eyelens, I inadvertently got water underneath the eyelens and decided to disassemble it to clear out the moisture. Upon unscrewing the field stop, the lenses tumbled out into a random jumble upon a towel I had placed under it before I had any chance to remove them in a controlled, graceful in-order fashion; fortunately none of the lenses got scratched. However, it was like putting a Chinese puzzle back together; I spent hours trying different permutations and looking at diagrams of various lens designs related to the Plossl family until finally I hit upon the unquestionably right one. That once was enough adventure into eyepiece disassembly for me to last a lifetime, except for the fact that T5 and T6 Naglers can be unscrewed neatly into two parts without otherwise undoing any of the internal lens assemblies.

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George N
Carpal Tunnel
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Reged: 05/19/06

Loc: Binghamton & Indian Lake NY
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: csrlice12]
      #5711385 - 03/03/13 08:20 PM

Quote:

Easier Listing of eyepieces you shouldn't disassemble:

1. All




Last year (2012) at NEAF I had a discussion with Don Yeier of VERNONscope. He said that proper assembly is very important for the performance of an eyepiece. He assembles each Brandon himself for that very reason. He said that only his son can do it as well as he can.

I have an old 16mm Nagler T2 that sometimes has its internal field stop un-screw. The first time it happened David Nagler talked me thru taking the thing apart over the phone and screwing the little ring back in place. I had to do it myself in the field one additional time.


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astro_baby
scholastic sledgehammer


Reged: 06/17/08

Loc: United Kingdom
Re: Comprehensive list of "Do Not Disassemble" eps new [Re: George N]
      #5711890 - 03/04/13 02:43 AM

The biggest problem I found, and ai only did it once on the rear lens assembly of a TAL finder is keeping everything clean. When your messing with tiny bits of glass, spacers, and in this case a reticule, even working on a clean surface with cotton gloves on and so forth ai had to do it about a zillion times before I was happy as there always seemed to be one more speck of grot inside the assembly.

Theres no way I'd risk it with an EP anymore than I would take a camera lens to bits.


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smallscopefanLeo
sage
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Reged: 01/23/11

Re: Comprehensive list of "Do Not Disassemble" eps new [Re: astro_baby]
      #5711899 - 03/04/13 03:05 AM

The only one I inadvertently attempted was my Surplus Shed 28mm RKE (as it spilled its guts into my lap a mere moment after I unscrewed the nose piece!) and while that is supposedly one of the simplest of multi-element eyepieces to dissect based on opinions I read here, it still had me scratching my head for a bit, and visiting our forum for photos that would soon help me make sure that I got the orientation right while gingerly putting it back together (all two groups of it, AND the middle spacer ring )!

It being surplus and slightly rough/imperfect to begin with, and the elements tumbling mere inches into velvety pliant clothing and lap (seems to be a common disassembly method here ), the reassembled end result came out looking unchanged to my eye .. which I was relieved about!


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