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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 12221
Loc: Los Angeles
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Out of all of this, one criticism of heavy eyepieces is valid and should be addressed by scope owners--when the eyepieces are so heavy they cause the focuser drawtube to sag down to the point the scope is out of collimation.
The cure is lighter eyepieces and/or stiffer focusers.
Since a heavy eyepiece can be balanced, I vote for the stiffer focusers.
By the way, removing the eyecup on the 30mm Meade UWA removes 1/2 lb (!), but I don't think you can easily modify the equivalent 31mm Celestron Axiom LX (which I think might be the heaviest eyepiece of all).
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Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member
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Lawrence Sayre
Abbe Normal
Reged: 10/16/04
Posts: 4746
Loc: N.E. Ohio
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I will agree that I found Delrin to be just about the perfect eyepiece upper lens housing and lower barrel material. The stuff is good looking, readily machinable, tough, light, and jet black.
I'm surprised that no factory eyepieces are utilizing it.
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My philosophy, in essence, is the concept of man as a moral being, with his own happiness as the moral purpose of his life, with productive achievement as his noblest activity, and reason as his only absolute.
Ayn Rand (in the appendix to 'Atlas Shrugged')
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russell23
sage
Reged: 05/31/09
Posts: 425
Loc: Upstate NY
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Quote:
I will agree that I found Delrin to be just about the perfect eyepiece upper lens housing and lower barrel material. The stuff is good looking, readily machinable, tough, light, and jet black.
I'm surprised that no factory eyepieces are utilizing it.
I really like the Delrin 19mm Konig I got from Russell optics. It is extrememly well machined, light, has a nice feel, and though I haven't used it in winter weather yet it is my understanding that the Delrin is easier to grip in the winter cold.
Have you machined eyepieces yourself with Delrin or did you get one from Russell Optics (again no relation to myself)?
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russell23
sage
Reged: 05/31/09
Posts: 425
Loc: Upstate NY
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Quote:
Out of all of this, one criticism of heavy eyepieces is valid and should be addressed by scope owners--when the eyepieces are so heavy they cause the focuser drawtube to sag down to the point the scope is out of collimation.
The cure is lighter eyepieces and/or stiffer focusers.
Since a heavy eyepiece can be balanced, I vote for the stiffer focusers.
By the way, removing the eyecup on the 30mm Meade UWA removes 1/2 lb (!), but I don't think you can easily modify the equivalent 31mm Celestron Axiom LX (which I think might be the heaviest eyepiece of all).
That is a real concern. Do you have any idea at what weight this concern becomes a problem? I know there is more than one variable because it probably also depends upon how far out you have to focus the eyepiece.
Dave
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Midnight Dan
Carpal Tunnel
Reged: 01/23/08
Posts: 2758
Loc: Brockport, NY
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Quote:
But, a little judicious choosing of eyepiece brands and types (there are about 1600 choices) could get all the eyepieces within a fairly narrow range of weights.
This is one reason I have stayed with the Hyperions across the range of focal lengths I need. They are all reasonably close to each other in weight.
I recently compared a few wide field EPs in the 30-36mm range and found the good ones to be way overweight - except for the Hyperion Aspheric 36mm. Apparently the aspheric lens design allows them to do the same job as the others with considerably less glass. The Aspheric weighs in very close to the weights of my other Hyperions allowing a similarly balanced set across all focal lengths.
I know that the quality of the Hyperions is not in the same league as many of the Televues, but they offer very good quality at a reasonable price, AND at a reasonable weight.
-Dan
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Scopes: Celestron NexStar 8SE, Orion EON 72mm ED/APO, Orion ShortTube 80
Mounts: NexStar Alt/Az GoTo, Orion Astroview (EQ3) w/single axis drive
Eyepieces: Baader Hyperion 36mm (Aspheric), 21mm 13mm, 8mm, 5mm;
Other: 2x & 3x Barlow, 0.63x Focal Reducer, Dew-not strips, DewBuster controller, SQM Meter
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Mike Hosea
Post Laureate
Reged: 09/24/03
Posts: 3945
Loc: "Metrowest" Boston
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Quote:
I'm surprised that no factory eyepieces are utilizing it.
The AP SPLs used Delrin as part of a novel mounting scheme. Basically the top is a Delrin cap that you can unscrew to gain access to a removable metal lens cell. The motivation for using Delrin there rather than aluminum, however, had nothing to do with weight, supposedly with Delrin being a more friendly material to the skin in insanely cold temperatures.
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Mike
Stuff that I use:
- 7" f/6.7 home-built Newt, eq platform, Pentax 40XW and 5XO, Tele Vue 13E and 2x Barlow, ZAO-II 6mm
- 120mm f/8.3 home-built grab-n-go Newt with 7-21mm Nikon Zoom
- Canon 15x50 IS and Eagle Optics 12x50 Ranger binoculars
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russell23
sage
Reged: 05/31/09
Posts: 425
Loc: Upstate NY
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Quote:
Quote:
But, a little judicious choosing of eyepiece brands and types (there are about 1600 choices) could get all the eyepieces within a fairly narrow range of weights.
This is one reason I have stayed with the Hyperions across the range of focal lengths I need. They are all reasonably close to each other in weight.
I recently compared a few wide field EPs in the 30-36mm range and found the good ones to be way overweight - except for the Hyperion Aspheric 36mm. Apparently the aspheric lens design allows them to do the same job as the others with considerably less glass. The Aspheric weighs in very close to the weights of my other Hyperions allowing a similarly balanced set across all focal lengths.
I know that the quality of the Hyperions is not in the same league as many of the Televues, but they offer very good quality at a reasonable price, AND at a reasonable weight.
-Dan
I'm considering trying out a 36mm Baader Hyperion at some point. As you know I was not happy with the edge performance of the lower cost 30-40mm 2" 70 degree eyepieces. I'm quite happy with my 2" 32mm UO Konig so I'm not sure if the 36mm Hyperion would gain very much for me. But if a used one shows up on CN or astromart I might give it a try.
Right now I have a 15.5mm and 13mm Russell optics Konigs on the way - also made with the delrin barrel. I'll be interested to see how much variation in weight they have.
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russell23
sage
Reged: 05/31/09
Posts: 425
Loc: Upstate NY
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By the way Dan, Do you know how many elements are in the 36mm Baader? Dave
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Luigi
Post Laureate
Reged: 07/03/07
Posts: 4940
Loc: MA
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Delrin is so passe. IMO, polyphenylenether would be a superior material. Lighter, better dimensional stability, harder and stiffer than acetal (AKA Delrin). But there are many other engineered plastics that could be considered.
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17.5" f/5 Dob. IM-715 MCT. 120ED. Lunt 60mm Ha.
Zeiss, Leica, Fujinon, Nikon, Pentax, Bushnell bins
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russell23
sage
Reged: 05/31/09
Posts: 425
Loc: Upstate NY
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Quote:
Delrin is so passe. IMO, polyphenylenether would be a superior material. Lighter, better dimensional stability, harder and stiffer than acetal (AKA Delrin). But there are many other engineered plastics that could be considered.
I've only owned the 19mm Delrin eyepiece for ~ 1 month. When you get down to the weight of Delrin, I don't think we need to go even lighter. Durability would be the only reason to use a different plastic. Is there anybody out there that has owned a Gary Russell eyepiece for a long enough time to be able to speak to the durability of the Delrin?
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JohnH
professor emeritus
Reged: 10/04/05
Posts: 734
Loc: vancouver near the wilds of B...
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I think that the people who gravitate (no pun inteded) to the larger Eps do so because they need them to achieve lower powers for wide fields of view. Would Televue have come up with the 41mm or their 31mm if people started buying (and making) bigger and bigger Dobsonians. A larger scope would not be as affected by a heavy eyepiece like a small 80mm refractor or an 6" travel Dob
Quote:
Another question...what are the lightest weight line of quality eyepieces?
And in your opinion...what are the worse offenders for the "Most Obese Eyepiece" award?
I could answer the first with a "4.8mm" made by a company whos name is close to that of a fermented drink made from honey.
The second is easy: 20mm Type 2 Nagler. When I got mine in the mail, I thought the guy had sold me a lead brick. 
I have a theory about why its a Type 2. The Type 1 20mm was so heavy, when it accidently rolled off the table and broke the concrete floor. 
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russell23
sage
Reged: 05/31/09
Posts: 425
Loc: Upstate NY
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For those that might be interested. I just received 3 new Russell-optics eyepieces today. One was a 15.5mm 2" Konig with a Delrin barrel. This has a mass of 140 grams - very close to the 19mm Konig which has a mass of 151 grams.
The next was a 2" 13 mm super Konig - which Gary's website indicates has 6 elements. The 13.0mm has a mass of 239 grams. The barrel is about 3/4 of an inch taller than the 15.5mm Konig and obviously the extra elements will add some weight. Actually looking back at my numbers it looks like my 12.5mm Orion edge on has a mass of 238 grams with the 2-1 1/4 adapter.
The last was a 2" 48mm 5 element superplossl. I gave up trying to draw out a used 48mm Brandon so I figured I give this one a try. The 48mm superplossl's barrel is not made from the Delrin. It has a regular aluminum barrel. The mass is 262 grams.
I'm not entirely sure what meaning one can get from this. If you compare the 6 element 2" 13mm SuperKonig to a 6 element 2" 12mm Type 4 Nagler, the Nagler has a mass of 459 grams against only 239 grams for the 13mm konig. On the other hand, a 7 element 13mm 1.25 inch Nagler Type 5 has a mass of 182 grams + 85grams for a 2-1 1/4" adapter would give a total mass of 267g. So in that comparison even with the Delrin housing the 13mm SuperKonig is not that much less in mass.
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