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Equipment Discussions >> Eyepieces

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5u4
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Reged: 04/27/06

Loc: FL
Who invented the barrel safety undercut?
      #5526417 - 11/18/12 04:25 PM

Wondering if anyone knows the origin of this ignoramus feature & why the vast majority of eyepieces available today come with it.

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Astrojensen
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Reged: 10/05/08

Loc: Bornholm, Denmark
Re: Who invented the barrel safety undercut? new [Re: 5u4]
      #5526440 - 11/18/12 04:35 PM

I don't know, but...


Clear skies!
Thomas, Denmark


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Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: Who invented the barrel safety undercut? new [Re: 5u4]
      #5526561 - 11/18/12 06:26 PM

I'm guessing some time in the late '80s because my earlier eyepieces definitely didn't have the groove.
Many of my eyepieces from the '90s didn't either, so it's only become fairly universal since 2000.


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Loren Toole
sage
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Reged: 03/23/04

Loc: New Mexico USA
Re: Who invented the barrel safety undercut? new [Re: Astrojensen]
      #5526564 - 11/18/12 06:27 PM

I've been reluctantly participating in this sales gimmick since it first appeared in the late 90s.... to the best of my knowledge, Televue was the first. Obviously this was an "innovation" at the time, but poorly considered since it also appeared when setscrews were being replaced by compression rings.

I believe it was the heavy Panoptics and Naglers that justified this extra safety feature...

Edited by Loren Toole (11/19/12 07:21 AM)


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herrointment
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Reged: 03/12/11

Loc: North of Hwy. 64
Re: Who invented the barrel safety undercut? new [Re: Astrojensen]
      #5526572 - 11/18/12 06:31 PM

I can't think of one EP I own that is easily removed from the diagonal.

Is there not a fortune to be made in replacement barrels?

No there is not. I do wish someone would try just for the ____ of it.


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Pollux556
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Reged: 12/14/08

Re: Who invented the barrel safety undercut? new [Re: 5u4]
      #5526586 - 11/18/12 06:35 PM

Thanks to this invention ! May be my 20mm Nagler T2 would not have been in such good condition.

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Scanning4Comets
Markus
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Reged: 12/26/04

Loc: Ontario, Canada
Re: Who invented the barrel safety undercut? new [Re: Pollux556]
      #5526602 - 11/18/12 06:41 PM

I hate this invention too. Eyepieces used to get hung up on my compression ring when I did have the ones with the safety undercut on them, but I have none because I use Antares Twist lock adapters on all of my 1.25" eyepieces and the 2" eyepieces I do have do NOT have the safety undercut on them.

I have two extension tubes that have this on them and I have tape in there wound right up until the undercut is GONE.

I steer clear of them.

However, if I used a diagonal and an EQ scope where the configurations of my scope move a lot, the safety undercut would be good to have in case one of the eyepieces were loose in the diagonal.


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jgraham
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Reged: 12/02/04

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Re: Who invented the barrel safety undercut? new [Re: Scanning4Comets]
      #5526688 - 11/18/12 07:35 PM

Grrrrr, I hate that darned 'feature'. I just dropped a set screw in the grass trying to get my eyepiece out! In some cases I've filled it in with aluminized tape.

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ibase
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Reged: 03/20/08

Loc: Manila, Philippines 121*E 14*N
Re: Who invented the barrel safety undercut? new [Re: jgraham]
      #5526712 - 11/18/12 07:46 PM

At one time it saved my Nagler 5T6 from falling onto hard concrete so I can't say that am hating 'em.

Best,


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Sarkikos
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Reged: 12/18/07

Loc: Scotophobe Maryland, USA
Re: Who invented the barrel safety undercut? new [Re: jgraham]
      #5526720 - 11/18/12 07:48 PM

Do we really need safety undercuts in eyepieces to keep them from falling out? There's little chance of that happening with my Dobs. The focusers are all slanted upwards at about 45 degrees or so. Unless the eyepieces jump up and out of the focuser on their own, they aren't coming out until I take them out. I only see that this "improvement" would make sense for refractors and SCTs and Maks. The focuser in those are at the wrong end of the tube!

I can say this. I have some of those scopes.


Mike

Diagonal? Isn't that just another name for the secondary mirror?


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herrointment
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Reged: 03/12/11

Loc: North of Hwy. 64
Re: Who invented the barrel safety undercut? new [Re: Sarkikos]
      #5526756 - 11/18/12 08:12 PM Attachment (41 downloads)

I DO have one EP that was easily removed from the holder thingy.

Never put it back after one look. It has a new job in the workshop....


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Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: Who invented the barrel safety undercut? new [Re: herrointment]
      #5526761 - 11/18/12 08:16 PM

Quote:

I DO have one EP that was easily removed from the holder thingy.

Never put it back after one look. It has a new job in the workshop....





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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Who invented the barrel safety undercut? new [Re: Astrojensen]
      #5526915 - 11/18/12 09:45 PM

Quote:

I don't know, but...


Clear skies!
Thomas, Denmark




Definitely a solution in desperate search of a problem.


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iluxo
sage


Reged: 09/23/08

Re: Who invented the barrel safety undercut? new [Re: Jeff Morgan]
      #5527019 - 11/18/12 10:52 PM

Thankfully my Vixen e.p.'s don't have this.

Unfortunately both my TMB ones do and its a major nuisance.


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Ed Kessler
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Reged: 05/17/06

Loc: Millersburg, PA
Re: Who invented the barrel safety undercut? new [Re: iluxo]
      #5527054 - 11/18/12 11:14 PM

Brandons don't have the undercut!!!

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davidpitre
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Reged: 05/10/05

Loc: Central Texas
Re: Who invented the barrel safety undercut? new [Re: Ed Kessler]
      #5527066 - 11/18/12 11:26 PM

When I am struggling to pull my $800. Ethos out of my $500. Paracorr I frequently think " Really? Is it necessary that I put up with this? This is the best you can do?"

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GeneT
Ely Kid
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Reged: 11/07/08

Loc: South Texas
Re: Who invented the barrel safety undercut? new [Re: 5u4]
      #5527162 - 11/19/12 12:35 AM

This is a situation where some eyepiece makers insist on forcing a design element that most users would rather not have.

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Mike B
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Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Who invented the barrel safety undercut? new [Re: GeneT]
      #5527199 - 11/19/12 12:58 AM

Quote:

Who invented the barrel safety undercut?




Wasn't that first developed by Mr. Safety, the TeleVue designer guy before Mr. Dellechiaie?


Yeah, i can envision where a Mak or 'fractor with a "secondary" mirror at the aft-end could suddenly loosen & twist 180-degrees with a glass grenade inserted, spilling the big guy onto the pavement or dirt. Yet how many instances of an expensive EP slipping from gloved fingers while suddenly hanging up by the dreaded undercut, and thence toppling from the focuser?

Instead, Mr. Safety, how about a short lanyard, fastened with some fancy schmancy proprietary system to the focuser, with a safety clip hooked at the EP? You could use the flange screw supplied with so many green-lettered EPs. ... or the hole it disappears from. I've actually done that with a pair of 12T4 Naglers in my BVer.

Otherwise, i have no use for safety undercuts.


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cjc
sage


Reged: 10/15/10

Loc: Derbyshire, England
Re: Who invented the barrel safety undercut? new [Re: Mike B]
      #5527315 - 11/19/12 04:08 AM

Thin shallow grooves on well fitting barrels would be worthwhile to me, if only they were standardised. However in practice undercuts range in depth from a sensible 0.2mm (Vixen NPL, Antares Ortho), to a ludicrous 0.6mm (TMB Planetary and ES), with the dimensions and profile of the undercut area also varying widely. Barrel sizes also vary with the Antares Ortho being an interference fit at 31.7mm compared with my 24mm ES68 which is significantly undersized at 31.4mm. The variations are such that when coupled with the misnamed compression ring, it is hardly surprising that there are problems.

Edited by cjc (11/19/12 04:09 AM)


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Jon Isaacs
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Who invented the barrel safety undercut? new [Re: cjc]
      #5527346 - 11/19/12 05:14 AM

Personally I like eyepieces with undercuts...

There are a few combinations that can result in an eyepiece getting hung up, the TMB Planetary's and the William Optics 2inch-1.25 inch do not always mate and it takes a bit of rock to get them free but in general they work just fine... Never have a problem with the TeleVue adapters or focusers/Paracorrs.

I do appreciate them with viewing with my 12.5 inch F/6 equatorial because sometimes the focuser is pointing down and the undercut adds a bit security, an eyepiece falling 5 or 6 feet and hitting concrete is worth avoiding.

Jon


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