AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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A question...why aren't eyepieces designed to reduce their overall weight?
The weight of some eyepieces is quite excessive leading to balance issues on the scope.
And there are materials out there that could be used to reduce their weight.
So why are "obese" eyepieces still the norm?
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AZStarGuy
professor emeritus
Reged: 05/05/08
Posts: 505
Loc: Scottsdale AZ
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Ron
SV102ABV
DSV-1 & Oberwerk
Pans,Naglers & Hyperions
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russell23
sage
Reged: 05/31/09
Posts: 423
Loc: Upstate NY
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Quote:
A question...why aren't eyepieces designed to reduce their overall weight?
The weight of some eyepieces is quite excessive leading to balance issues on the scope.
And there are materials out there that could be used to reduce their weight.
So why are "obese" eyepieces still the norm?
The eyepieces that seem to have the biggest issues with weight are typically either some of the very long FL eyepiecees (30mm and more) or the high end eyepieces from TV, Pentax, Meade. They do create balance problems and I factor that in when I'm considering a purchase.
I can't speak to the details of eyepiece design, but I think that it is safe to say that if you want to have a wide field 70 - 100 degree eyepiece with excellent edge correction you need more glass and that adds your weight.
As far as lighter weight materials, Russell-optics (no relation to myself) uses lightweight Delrin Plastic for his eyepieces. Here is a link:
http://www.russell-optics.com/2_inch_eyepieces
Gary Russell offers most of his eyepieces in a 2" format even though most of them could fit in a 1.25" housing. But they are lightweight and the Delrin has a nice feel - which I think will be great in cold weather.
There are lots of lightweight options out there. It depends upon what you are looking for in an eyepiece. If you want great edge correction in a longer FL, you're probably looking at a heavier eyepiece.
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hfjacinto
Almost got me
Reged: 01/12/09
Posts: 2088
Loc: Union,NJ
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Some eyepieces are very light for there size (like the Hyperion aspehrics) but if you want light eyepieces, I have 1 or 2 SUPER HIGH POWER plastic Huygenians that came with a scope I long threw out.They weigh barely anything and the small one will give you 500X.
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C9.25 ASGT 9*50 MM Finder,FT Focuser & 2" Diagonal
Meade LXD 75 6 Inch SNT w 9*50 MM Finder
5,6,9,14.5 MM Zhummel Planetary EPs
13,17,21,24,31,36 MM Baader Hyperion
6.7,8.8 MM Meade UWA & 11 MM Nagler T6
Planetary, OIII and Narrowband Filters
Thousand Oaks Dew Control w Kendrick Heaters
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FirstSight
Post Laureate
Reged: 12/26/05
Posts: 3892
Loc: Raleigh, NC
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Quote:
A question...why aren't eyepieces designed to reduce their overall weight?
The weight of some eyepieces is quite excessive leading to balance issues on the scope.
In part it's because there are also some other competing objectives that many people find very desirable in eyepiece designs, such as width of AFOV and creating a sense of "immersiveness, the achievement of which also as a corollary tends to increase the difficulty of fulfilling another important design objective - minimizing aberrations. In short, fulfilling any of these design factors (especially all together) tends to require wider, sometimes thicker lens elements, and more of them. It's much harder to minimize weight while achieving these design objectives than it is with simpler three-element (narrower AFOV) designs like Orthos or even Plossls (many of which aren't necessarily simple three-element designs anymore).
If Al Nagler couldn't figure out a way to make a 31T5 Nagler lighter at the time it came out, it was probably extraordinarily difficult to get a sharp, minimally aberrated 82-degree widefield in a package much lighter and smaller. But nonetheless, TeleVue must consider weight/bulk reduction to be an extremely important objective - the Ethos line is much less dense in weight/size ratio compared to The T4 or T5 Naglers. ALL five members of the Ethos family released so far weigh in at between one and one and a quarter pounds. My guess is that what's slowed TeleVue from releasing the final member of the Ethos line (somewhere between twenty and twenty-five mm focal length) isn't the feasibility of producing an optically excellent eyepiece at a suitable point within that range, but rather doing so within as desirable a limit on bulk and weight as possible.
As to cost of materials used - it isn't the bulk raw silicate glass that's the major component of cost, but rather:
a) the exotic elements added to suitably alter/improve the refractive/transmissive properties of the glass
b) the processing of the glass to obtain suitably high quality for lens-making (rather than e.g. ordinary window-pane) glass
c) the amount of grinding, polishing, coating, etc needed to make a high-performance lens element
So - I'm not sure how much cost advantage could be feasibly gained if was possible for telescope lens maker to switch to some form of polycarbonate rather than glass as the base material - its use in eyeglass lenses suggests there might be some, but OTOH telescope lenses involve additional considerations than do eyeglasses to achieve the necessary performance. The bottom line, however is that a huge component of the cost isn't simply the primary bulk of raw materials involved, but the exotic elements needed plus the processing. Maybe technological advances will change this in the future, but for now, there's good reason TeleVue and Pentax are sticking mainly to (exotic, more expensive) glasses for telescope lenses.
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Chris M., aka "First Sight"
Orion XT12i Dob with Moonlite CR-2 focuser
WO Megrez 90 refractor on UniStar Light mount
Nikon 10x50 Binoculars
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FirstSight
Post Laureate
Reged: 12/26/05
Posts: 3892
Loc: Raleigh, NC
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Quote:
Some eyepieces are very light for there size (like the Hyperion aspehrics) but if you want light eyepieces, I have 1 or 2 SUPER HIGH POWER plastic Huygenians that came with a scope I long threw out.They weigh barely anything and the small one will give you 500X.
Ethos eyepieces seem (and feel in the hand) fairly light for their size, especially given their extreme performance characteristics. All five Ethos focal-lengths available so far weigh in at between a pound and a pound and a quarter, with most toward the lighter figure.
None of them give me any balance problems in either of my scopes (12XTi dob, 90mm refractor), except to a very minor extent at very low altitude angles. Even when they do, either a very light touch of the hand or application of a simple half-pound adjustable counterweight (or with the dob, tightening the insta-adjust knob a small turn) takes care of the problem completely, without any significant hassle at all.
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Chris M., aka "First Sight"
Orion XT12i Dob with Moonlite CR-2 focuser
WO Megrez 90 refractor on UniStar Light mount
Nikon 10x50 Binoculars
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Glass is glass..I understand that.
But take a look at your large heavy eyepieces..there are plenty of areas where weight could be saved.
Does anyone use carbon fiber in their eyepieces?
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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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?
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stana
member
Reged: 05/30/09
Posts: 25
Loc: Czech republic
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Lightes eypieces? Maybe Plossl..
/Only four elements../
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Old man /43 year old/, who is Ethoi and fan clear sky../Dobson 12", E-13, E-8, Pan 19, Powermate 2x and UHC Astronomik.
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Lawrence Sayre
Abbe Normal
Reged: 10/16/04
Posts: 4742
Loc: N.E. Ohio
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The T6 Nagler's sure represented a phenomenal case of downsizing without sacrificing optical quality. They are tiny by comparison to their predecessors.
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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: 423
Loc: Upstate NY
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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 don't think eyepiece weight is as widespread a problem as you seem to think. Many of the top end TV, Pentax, Meade wide field eyepieces are quite heavy (again varies with FL in each line) - as well as some of the lower cost 2" long FL eyepieces. Outside of those most eyepieces are quite light. What weight do you consider too heavy?
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slyke
super member
Reged: 02/21/08
Posts: 116
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If you excuse the 28mm then the UWAN line are all reasonable small for 82 deg eyepieces.
-Stephen
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Brian Schmidt
sage
Reged: 01/25/09
Posts: 204
Loc: Roswell, GA
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I know it has been said, but it's worth saying again... the T6 naglers are amazingly light for the wide sharp field of view that they provide. I use 2 of them along with a 24 Pan, which is about the same weight. Very light, which worked out good for me since heavy oculars annoy me.
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Brian
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BillP
Post Laureate
Reged: 11/26/06
Posts: 3934
Loc: Vienna, VA
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IMO, many are still rather heavy for marketing purposes as it conveys the perception of quality. Not to pick on TV as many do things like this, but just because I am so familiar with them, if you look at the original 4.8mm Nagler it was a little brick when you lifted it. I took mine apart and as soon as you unscrew the barrel you discover the top housing with the majority of the lenses is light as a feather. The barrel upon examination is very very heavy guage brass and where all the weight comes from. I also consider my Radians quite heave EPs for the size. Do the same thing and unscrew the barrel, again the large top housing with all the glass is super light, and looking at the barrel it has large sections of very thick chromed brass -- again where all the weight is. The 2" Pans IMO are quite heavy also, but was not brave enough to take apart my 35 Pan as too many stories of Pan elements falling out (like from the 19mm). So IMO, a lot has to do with conveying the feel of high quality...which is an important thing.
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Bill Paolini
XT10i Dob---TSA-102 S-APO---APM80/480 S-APO--- P.S.T.
TMB Supermonos---Meade UWAs---TV Panoptic---AT Titan II ED
To your own eyes be true...
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pankhi
member
Reged: 01/26/08
Posts: 92
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Harry Siebert would know the answer. His excellent eyepieces feel featherweight compared to my Hyperions. You can get Harry Siebert's phone number from his website Siebert Optics. Knowing Harry, he'll be happy to chat with you.
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Mysteries of night escape the light of day – Neil Peart, RUSH
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E_Look
Pooh-Bah
Reged: 03/06/08
Posts: 1207
Loc: near New York
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I don't know much about Thomas M. Back's nor Burgess Optical's other offerings, but I do have the (BO/)TMB Planetary series eyepieces and they are not heavy at all. And what heft there is makes them feel nice in the hand. Their ultimate performance may be debatable, but that they are at least slightly more than just okay eyepieces is not and they never truly throw an OTA out of balance even if you switch from the 9 mm to the 2.5 mm. They aren't all that large either, even if they are over three times the dimensions of an average standard Plössl. And like someone here said, if size and/or weight is a real issue, Plössls offer very good performance for their size and mass.
*EDIT*
I also have the 21 mm Stratus. Now THAT is a fairly big and somewhat heavy eyepiece. I did once have to be careful with how I moved my scope on its mount because of it. That Stratus is much more than double the average size and weight of a BO/TMB or TMB Planetary
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Ed
Edited by E_Look (07/02/09 11:53 AM)
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jrbarnett
Eyepiece Hooligan
Reged: 02/28/06
Posts: 4345
Loc: Petaluma, CA
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Actually all of the really good eyepieces are light weight. 
The best eyepieces have four or fewer lens elements, and some even have lightweight aluminum (rather than chrome plated brass) barrels. A full set of Brandons or Meade Research Grade Orthoscopics, for example, weigh less than a single Type 5 Nagler or Pentax XW. (Oink, oink!)
I suspect the reason for porky-pieces is that most buyers would be disappointed if their $500 baby didn't have "heft".  On a more serious note, it may take more metal to hold a half-score of oddly shaped, thick glass elements securely in their intended positions.
Regards,
Jim
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"I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."
- Sir Issac Newton
Edited by jrbarnett (07/02/09 11:59 AM)
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Eddgie
Carpal Tunnel
Reged: 02/01/06
Posts: 2703
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The T6 Naglers represent a perfect case in point as to why some eyepieces are heavier than others, and the best two eyepieces to use for this comparison would be the 17mm T4 and the 16mm T5.
While many would say that the smaller and lighter 16mm is the result of evolution, these eyepeices are actually quite different in their characteristics.
The T4 was designed to have excellent eye relief for its focal length, and to have a very minumum of pincushion distortion.
The T6 on the other hand was designed to be smaller and lighgter, but at the EXPENSE of having slightly less eye relief and somewhat greater pincushion distortion.
That is why Televue still offeres both eyepieces even though they are very close in focal length. The T6 isn't necessarily "Better" but rather it is a bit of a tweaked compromise that sacrifices eye relief and adds field distortion, but is lighter, much more compact, and costs less.
So, a perfect example of why some eyepieces are big and heavy. The have to be for the designer to acheive his/her design requirements.
I have owned many less expensive widefield eyeices that were much lighter and much less expensive, but none have come close to the edge performance of the T4 naglers and the 31mm T5. The extra weight is worth it.
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Celestron C14, CGE (Big Al)
Astro-Physics 6" f/8 (Buffy)
Televue 101 (No name, but I call it my Widescreen HD Space TV)
The night sky is my mistress. She seduces me away from all other lovers.
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Eddgie
Carpal Tunnel
Reged: 02/01/06
Posts: 2703
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And on that same line of reasoning, I also owned another eyepiece that was an 82 degree AFOV in a similar focal length. 18mm Meade UWA.
I wrote a review of that eyepiece and while I was impressed with it optically, I BLASTED its packaging. It was far bulkier and heavier than it needed to be. The big ugly shroud with the cam sleeve that rasied it and lowered it added several ounces and a lot of blulk to what was otherwise and excellent eyepiece.
I tried using it with the shroud removed, which made it much more compact and several ounces lighter, but it looked home-made as a result, and I could not find a dust cap to fit it. I put the shroud back on and sold it.
What was Meade THINKING when they did that. Another difference between the 16mm and 17mm Nagler is that the T4 also includes a shroud (Instajust, which love it or hate it, does work as the designer intended and was superrior in every way to the Meade shroud).
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Celestron C14, CGE (Big Al)
Astro-Physics 6" f/8 (Buffy)
Televue 101 (No name, but I call it my Widescreen HD Space TV)
The night sky is my mistress. She seduces me away from all other lovers.
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Interesting that not one post so far has listed the weight of the eyepieces they have discussed. ;<)
It reminds me of a comment I heard one night at a star party..."Does this eyepiece make my scope look fat?"
Considering that balancing a scope is a big issue, weight does matter.
Has anyone substituted a lighter weight barrel on a heavy eyepiece?
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russell23
sage
Reged: 05/31/09
Posts: 423
Loc: Upstate NY
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Quote:
Interesting that not one post so far has listed the weight of the eyepieces they have discussed. ;<)
It reminds me of a comment I heard one night at a star party..."Does this eyepiece make my scope look fat?"
Considering that balancing a scope is a big issue, weight does matter.
Has anyone substituted a lighter weight barrel on a heavy eyepiece?
As I asked earlier - what weight do you consider too heavy? A 31mm T5 Nagler weighs 35oz, a 22mm T4 Nagler weighs 24oz. Is the 31mm heavy? The 22mm? Or how about a 27mm Panoptic at 16oz?
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jrbarnett
Eyepiece Hooligan
Reged: 02/28/06
Posts: 4345
Loc: Petaluma, CA
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Yes, yes and yes.
Regards,
Jim
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"I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."
- Sir Issac Newton
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Paul G
Carpal Tunnel
Reged: 05/08/03
Posts: 2269
Loc: Freedonia
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Quote:
Does anyone use carbon fiber in their eyepieces?
Not sure it would have a place in an eyepiece. If it replaced the aluminum housing there would be little weight savings, and the business end, the barrel, isn't appropriate for such a material. Imagine tightening the end of a setscrew into carbon fiber.
Plastic to replace the heavy barrel would make a significant difference and would be sturdy enough but might mar more easily. However, given all the whining you see here about the cost of large premium eyepieces can you imagine the howl if a $500 eyepiece were made of plastic? 
Heft gives the impression of quality. Heavy automobile doors that close with a thud are one example. Considerable engineering goes into making a quality-inspiring sound. The LS460's door was engineered to sound like a heavy oak door. My binoculars are another example of the impression weight makes. The Leicas are made of various metals and have a substantial feel in the hand, while the latest Zeiss of similar optical quality but with some type of composite body feel light and "cheap" despite their price.
And the large eyepieces have big chunks of glass. The 31 Nagler has one element that's larger than the objective of a Pronto.
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Gus
Tasco 4.5 Reflector EQ Telescope
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Jim Rosenstock
Post Laureate
Reged: 07/14/05
Posts: 3712
Loc: MD, south of the DC Nebula
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Quote:
It reminds me of a comment I heard one night at a star party..."Does this eyepiece make my scope look fat?"
That's the best line I've heard in a while!!!
If Dr. Freud were around, I'm sure he'd have a few things to say about this thread...
...once he removed his cigar, of course.
Jim
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QUESTION AUTHORITY!
"errr....sez who??"
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nightstalker
sage
Reged: 03/30/07
Posts: 252
Loc: Great South Land
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Great thread .. My 8.5 pentax xf actually feels alarmingly light for its size , I've been quite concerned for it for some time now 
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28pretoria22t414xw8.5xf
12" truss dob and numerous missplaced accesories...graham
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gnowellsct
professor emeritus
Reged: 06/24/09
Posts: 730
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Balancing a scope IS a big issue, but you know, it is only an issue for SOME scopes. German equatorial/SCT configurations are fairly immune to many of the balance issues that plague dob users.
People who have servo go-to Dobs, which is a fair number of people these days, also are immune to the balance issue.
On my gem-mounted refractors I've never had to worry about balance.
If you have a refractor on a Gibraltar, you need to worry. And I have heard you need to worry on disc mount. I define worry as having to do anything.
Once I've set my scope or scopes up for the night, I'm done with the balance issue regardless of what eyepiece I put in. The most I might do is tighten, or loosen, a clutch.
So, to conclude, a lot of scope owners are not worrying about weight, and do not figure it into their calculations.
However, we pay for that in setup time. If you have a simple undriven dob you can set up fast, in some cases in a minute or so, but now you've got the eyepiece weight issue.
regards
greg n
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"Aperture will get you through times of no money better than money will get you through times of no aperture."
featuring selected astrojunk:
bunch o' widefield eyepieces
bunch o' narrowfield eyepieces
couple o' Barlows
couple o' scopes
couple o' mounts
couple o' tripods
and a pier 'n' stuff
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jrbarnett
Eyepiece Hooligan
Reged: 02/28/06
Posts: 4345
Loc: Petaluma, CA
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Imbalance is only one of several "ills" of excessively porky eyepieces.
A case full of eight-element eyepieces is heavy and adds to the hassle of loading and unloading as a result. A tall, heavy eyepiece is more apt to unscrew an SCT diagonal during a slew. A heavy eyepiece is more apt to damage itself on impact than a lighter one (hits with more force). Those are just a few examples.
The number of ills associated with lower weight eyepieces is smaller (like everything else about them ).
Regards,
Jim
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"I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."
- Sir Issac Newton
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
Quote:
Interesting that not one post so far has listed the weight of the eyepieces they have discussed. ;<)
It reminds me of a comment I heard one night at a star party..."Does this eyepiece make my scope look fat?"
Considering that balancing a scope is a big issue, weight does matter.
Has anyone substituted a lighter weight barrel on a heavy eyepiece?
As I asked earlier - what weight do you consider too heavy? A 31mm T5 Nagler weighs 35oz, a 22mm T4 Nagler weighs 24oz. Is the 31mm heavy? The 22mm? Or how about a 27mm Panoptic at 16oz?
It's like the old saying.."One can never be too rich or too thin"...or your eyepiece too light.
Lighter is better...much lighter is much better.
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
Quote:
Does anyone use carbon fiber in their eyepieces?
Not sure it would have a place in an eyepiece. If it replaced the aluminum housing there would be little weight savings, and the business end, the barrel, isn't appropriate for such a material. Imagine tightening the end of a setscrew into carbon fiber.
Plastic to replace the heavy barrel would make a significant difference and would be sturdy enough but might mar more easily. However, given all the whining you see here about the cost of large premium eyepieces can you imagine the howl if a $500 eyepiece were made of plastic?
Heft gives the impression of quality. Heavy automobile doors that close with a thud are one example. Considerable engineering goes into making a quality-inspiring sound. The LS460's door was engineered to sound like a heavy oak door. My binoculars are another example of the impression weight makes. The Leicas are made of various metals and have a substantial feel in the hand, while the latest Zeiss of similar optical quality but with some type of composite body feel light and "cheap" despite their price.
And the large eyepieces have big chunks of glass. The 31 Nagler has one element that's larger than the objective of a Pronto.
Carbon fiber would work well...just like it does in OTAs.
Weight is weight...and it is undesirable in an eyepiece in relation to function.
Many of the comments sound like "these extra 20 pounds I am carrying on my waist actually serve a purpose" when the truth is that they affect the telescope in a negative manner.
When I assess eyepieces, their weight is taken into account since it affects the scope and mount.
As for setscrews having an effect, that is poor design of the focuser. Any focuser worth having has a compression ring to properly retain an eyepiece.
And a nasty habit people have is to overtighten their setscrews because...the eyepiece is too heavy and will fall out.
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Tamiji Homma
Pooh-Bah
Reged: 02/24/07
Posts: 1084
Loc: California, USA
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Quote:
Imbalance is only one of several "ills" of excessively porky eyepieces.
A case full of eight-element eyepieces is heavy and adds to the hassle of loading and unloading as a result. A tall, heavy eyepiece is more apt to unscrew an SCT diagonal during a slew. A heavy eyepiece is more apt to damage itself on impact than a lighter one (hits with more force). Those are just a few examples.
The number of ills associated with lower weight eyepieces is smaller (like everything else about them ).
Regards,
Jim
Here is datapoint, weight measurement of eyepiece without caps.
Those three eyepieces are very light for its focal length.
81.0 25.0 Zeiss-Asphical 1.25"
75.0 28.0 Siebert-UW 1.25"
68.0 23.0 SV23
Code:
gram focal name
958.0 28.0 WO-UWAN
771.0 30.0 BW-Optik/Zeiss
722.0 17.0 TV-Ethos
678.0 22.0 TV-Nagler
555.0 50.0 Tak-LE
530.0 42.0 Vixen-LVW
492.0 40.0 TMB-Paragon
424.0 3.5 Pentax-XW
390.0 10.0 Pentax-XW
358.0 20.0 Pentax-XW
354.0 31.0 Hyperion 2" mode
308.0 32.0 Edmunds-RKE
298.0 24.0 Hyperion 2" mode
291.0 30.0 TMB-Paragon
248.0 14.0 Denkmeier
237.0 16.0 WO-UWAN
179.0 19.0 TV-Panoptic
175.0 32.0 TV-Plossl
160.0 30.0 Tak-LE
150.0 3-6 TV-Nagler-Zoom 3-6
133.0 5.0 Tak-LE
131.0 3.6 Tak-LE
101.0 12.5 Tak-LE
89.0 5.1 Pentax-XO
84.0 16.0 ZAO2
81.0 25.0 Zeiss-Asphical 1.25"
75.0 28.0 Siebert-UW 1.25"
73.0 15.0 TV-Plossl
68.0 23.0 SV23
67.0 10.0 ZAO2
66.0 6.0 ZAO2
64.0 11.0 TV-Plossl
62.0 4.0 ZAO2
56.0 7.0 TMB-mono
Tammy
Edited by Tamiji Homma (07/03/09 02:50 PM)
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russell23
sage
Reged: 05/31/09
Posts: 423
Loc: Upstate NY
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Quote:
Quote:
Quote:
Interesting that not one post so far has listed the weight of the eyepieces they have discussed. ;<)
It reminds me of a comment I heard one night at a star party..."Does this eyepiece make my scope look fat?"
Considering that balancing a scope is a big issue, weight does matter.
Has anyone substituted a lighter weight barrel on a heavy eyepiece?
As I asked earlier - what weight do you consider too heavy? A 31mm T5 Nagler weighs 35oz, a 22mm T4 Nagler weighs 24oz. Is the 31mm heavy? The 22mm? Or how about a 27mm Panoptic at 16oz?
It's like the old saying.."One can never be too rich or too thin"...or your eyepiece too light.
Lighter is better...much lighter is much better.
Ok, but that doesn't really answer my question. At what weight (in grams or ounces) would you be satisfied that an eyepiece is not creating problems for you because of its weight?
This is not an irrelevant question. Your problem cannot be fixed until there is a target weight you're shooting for. If "the lighter the better" is your only criteria, then I'm sure somebody out there has some 0.965" eyepieces with plastic lenses they'd be willing to give away for the cost of postage.
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Starpoke
sage
Reged: 11/14/07
Posts: 275
Loc: Western Montana
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I have one that unbalances every scope I have tried it in, plus it really needs the safety groove because on a GEM the normal tube rotation as one slews puts enough torque on it to automatically point it to the ground. I am speaking of the 35mm. Scopos Extreme. It is not only heavy at 1090g. (38.2 oz.) but tall and wide as well. I have to move the Brandon forward about 2" when I put it in but it does have a nice sharp 70 degree field. I use it rarely because it feels so precarious but I love the 3.7 degree FOV. which is slightly larger but much darker than the 3.65 I get with the 48mm. Brandon ep. with its 50 degree field. I probably would be happier with the 36mm. Hyperion Aspheric. (Naglers and Pans are presently out of reach.)
It nearly doubles the weight of my WO 66 petzval but the 6 degree plus FOV is really nice.
Clear skies
Glenn
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152nn f9 Starfire Apo on Schaefer AT-4 Mount
94mm f7 Brandon Apo on ASGT (or Polaris when AGST is on the fritz.)
WO Zenithstar 66 f6 ED Pretzval on UA Microstar
Tasco 7TE-5 60mm. f16.7 EQ Refractor.
Celestron C-60E f15 on Polaris
Celestron CO 62 Cometron f5
Meade 390 90mm f11 on Mizar m-4
Tasco 8V
eyepieces, books, some old scopes and mounts - ect.
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Starpoke
sage
Reged: 11/14/07
Posts: 275
Loc: Western Montana
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The E.P. plus the Williams CF diagonal tips the scale at 3 lbs 7 oz.
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152nn f9 Starfire Apo on Schaefer AT-4 Mount
94mm f7 Brandon Apo on ASGT (or Polaris when AGST is on the fritz.)
WO Zenithstar 66 f6 ED Pretzval on UA Microstar
Tasco 7TE-5 60mm. f16.7 EQ Refractor.
Celestron C-60E f15 on Polaris
Celestron CO 62 Cometron f5
Meade 390 90mm f11 on Mizar m-4
Tasco 8V
eyepieces, books, some old scopes and mounts - ect.
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Starpoke
sage
Reged: 11/14/07
Posts: 275
Loc: Western Montana
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The scope is barely heavier at 3 lbs. 13 oz.
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152nn f9 Starfire Apo on Schaefer AT-4 Mount
94mm f7 Brandon Apo on ASGT (or Polaris when AGST is on the fritz.)
WO Zenithstar 66 f6 ED Pretzval on UA Microstar
Tasco 7TE-5 60mm. f16.7 EQ Refractor.
Celestron C-60E f15 on Polaris
Celestron CO 62 Cometron f5
Meade 390 90mm f11 on Mizar m-4
Tasco 8V
eyepieces, books, some old scopes and mounts - ect.
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
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Interesting that not one post so far has listed the weight of the eyepieces they have discussed. ;<)
It reminds me of a comment I heard one night at a star party..."Does this eyepiece make my scope look fat?"
Considering that balancing a scope is a big issue, weight does matter.
Has anyone substituted a lighter weight barrel on a heavy eyepiece?
As I asked earlier - what weight do you consider too heavy? A 31mm T5 Nagler weighs 35oz, a 22mm T4 Nagler weighs 24oz. Is the 31mm heavy? The 22mm? Or how about a 27mm Panoptic at 16oz?
It's like the old saying.."One can never be too rich or too thin"...or your eyepiece too light.
Lighter is better...much lighter is much better.
Ok, but that doesn't really answer my question. At what weight (in grams or ounces) would you be satisfied that an eyepiece is not creating problems for you because of its weight?
This is not an irrelevant question. Your problem cannot be fixed until there is a target weight you're shooting for. If "the lighter the better" is your only criteria, then I'm sure somebody out there has some 0.965" eyepieces with plastic lenses they'd be willing to give away for the cost of postage.
No games...I gave you the answer.
Lighter is better.
I have a number of scopes so the "correct" weight would be different for each scope.
What's the right and only weight for you?
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russell23
sage
Reged: 05/31/09
Posts: 423
Loc: Upstate NY
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Quote:
Quote:
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Interesting that not one post so far has listed the weight of the eyepieces they have discussed. ;<)
It reminds me of a comment I heard one night at a star party..."Does this eyepiece make my scope look fat?"
Considering that balancing a scope is a big issue, weight does matter.
Has anyone substituted a lighter weight barrel on a heavy eyepiece?
As I asked earlier - what weight do you consider too heavy? A 31mm T5 Nagler weighs 35oz, a 22mm T4 Nagler weighs 24oz. Is the 31mm heavy? The 22mm? Or how about a 27mm Panoptic at 16oz?
It's like the old saying.."One can never be too rich or too thin"...or your eyepiece too light.
Lighter is better...much lighter is much better.
Ok, but that doesn't really answer my question. At what weight (in grams or ounces) would you be satisfied that an eyepiece is not creating problems for you because of its weight?
This is not an irrelevant question. Your problem cannot be fixed until there is a target weight you're shooting for. If "the lighter the better" is your only criteria, then I'm sure somebody out there has some 0.965" eyepieces with plastic lenses they'd be willing to give away for the cost of postage.
No games...I gave you the answer.
Lighter is better.
I have a number of scopes so the "correct" weight would be different for each scope.
It is hard then to understand what you're looking for when you started this thread. Was the point just to complain that some eyepieces are heavy? Which eyepieces? At what weight do they become a problem for you? What is your criteria for the weight being a problem? Because it causes balance problems with your mount? Problems for the focuser? Problems for the locking mechanism of the diagonal?
It just seems odd me that you would start this thread and then be so vague in describing what your problem is. It makes it very difficult for those of us that are actually interested in the question you raised to respond in anything other then generalities.
Quote:
What's the right and only weight for you?
This is much like what I asked you and it is not a hard question to answer. I have found that in my scope, any eyepiece that weighs more than ~16-17oz is too heavy to maintain the balance of the refractor in my mount if I switch to the other eyepieces I own.
The heaviest eyepiece I have is a 27mm Pan - which weights just over 16oz. I can use that along with any of the other 10 eyepieces I have and there are no significant balance problems in switching.
When I had a 38mm Orion Q70 - which weighs in at around 21-22oz, it was impossible to balance the OTA in the rings for the 38mm and then switch to my lighter eyepieces.
Of course the heavier eyepieces would not be a problem - if all of my eyepieces were heavier. So another solution to the problem would be rather than make eyepieces lighter - strive to make them heavier. I don't actually advocate that. The problem - for my scope set-up - is that if there are big differences in eyepiece weight it throws of the balance. In theory any eyepiece would be ok as long as I'm either not switching eyepieces or switching to eyepieces that have similar weight.
That explanation is quite a bit different than just saying "lighter is better". I agree with the sentiment, but at some point physics, optical design, and quality get in the way.
Someone mentioned earlier that they felt the Naglers are made of heavier barrel construction than needed. And that may be so. I'm hesitant to pick up a 22T4 Nagler because it weights 24oz. If it could be pared down to 16oz with lighter barrel materials that would interest me.
I wonder if the TV lense assemblies could be put into a Delrin type housing such as that Gary Russell (no relation) uses in his eyepieces?
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russell23
sage
Reged: 05/31/09
Posts: 423
Loc: Upstate NY
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Let me add one other thought here too. In the case of the scope and mount I'm using, lighter is not necessarily better. If I use really light eyepieces, I have to drop the tube further back in the rings so that the objective does not overwhelm the star diagonal/eyepiece. So in that situation a lighter eyepiece forces the diagonal closer to the ground - which can be less comfortable. When I put in a heavier eyepieces, the tube is placed such that the eyepiece can be higher above the ground.
I can also adjust for this by adjusting the legs, but the point is lighter can create its own problems.
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Actually you raise another good point...why isn't there a predefined weight that all eyepieces are designed to?
If there was ONE weight, all scope assemblies could be set to balance on that one value and using a scope would be much simpler.
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 12221
Loc: Los Angeles
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Doesn't this depend on whether the scope is balanced for a certain weight at a certain point? With my lightest eyepiece and the scope pointed near zenith, I have to dangle a counterweight from the UTA of my scope.
With a 31 nagler at the horizon, I have to add a 5lb counterweight to the mirror box.
There is NO weight that would be perfectly balanced near the zenith AND the horizon, so some form of counterweight will always be necessary unless the scope is so large the weight of the eyepiece is insignificant, or so "sticky" that the difference in the weight of eyepieces causes no noticeable balance changes.
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Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member
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Tamiji Homma
Pooh-Bah
Reged: 02/24/07
Posts: 1084
Loc: California, USA
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Quote:
Actually you raise another good point...why isn't there a predefined weight that all eyepieces are designed to?
If there was ONE weight, all scope assemblies could be set to balance on that one value and using a scope would be much simpler.
Because size/weight/shape of telescope/mount etc are vastly different as primary eyepiece design parameters (focal length, AFOV, eye relief, glass, cost, ...) are vastly different.
If you demand optical engineers "one size fits all or telescope balancing issue by eyepiece" type requirement as mandatory design parameter, I suspect you will be disappointing result of product in terms of optical quality, mechanical robustness, price etc.
I believe free to design anyway you want is much better solution so that we consumers can choose whatever our liking 
If you sort my weight measurement in eyepiece focal length, it tells something: Some eyepiece weight is more than 10x than other with the same focal length.
Code:
Partial list where it is interesting:
grams F/L model name
237.0 16.0 WO-UWAN
84.0 16.0 ZAO2
722.0 17.0 TV-Ethos
179.0 19.0 TV-Panoptic
358.0 20.0 Pentax-XW
678.0 22.0 TV-Nagler
68.0 23.0 SV-Plossl
298.0 24.0 Hyperion
81.0 25.0 Zeiss-Ortho
75.0 28.0 Siebert-UW
958.0 28.0 WO-UWAN
771.0 30.0 BW-Optik/Zeiss
291.0 30.0 TMB-Paragon
160.0 30.0 Tak-LE
354.0 31.0 Hyperion
308.0 32.0 Edmunds-RKE
175.0 32.0 TV-Plossl
Tammy
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
Doesn't this depend on whether the scope is balanced for a certain weight at a certain point? With my lightest eyepiece and the scope pointed near zenith, I have to dangle a counterweight from the UTA of my scope.
With a 31 nagler at the horizon, I have to add a 5lb counterweight to the mirror box.
There is NO weight that would be perfectly balanced near the zenith AND the horizon, so some form of counterweight will always be necessary unless the scope is so large the weight of the eyepiece is insignificant, or so "sticky" that the difference in the weight of eyepieces causes no noticeable balance changes.
Or the scope/mount is designed for one predetermined eyepiece weight.
That is my point...one predetermined weight that all eyepieces are designed to.
It would make the field usage of eyepieces much easier.
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
Quote:
Actually you raise another good point...why isn't there a predefined weight that all eyepieces are designed to?
If there was ONE weight, all scope assemblies could be set to balance on that one value and using a scope would be much simpler.
Because size/weight/shape of telescope/mount etc are vastly different as primary eyepiece design parameters (focal length, AFOV, eye relief, glass, cost, ...) are vastly different.
If you demand optical engineers "one size fits all or telescope balancing issue by eyepiece" type requirement as mandatory design parameter, I suspect you will be disappointing result of product in terms of optical quality, mechanical robustness, price etc.
I believe free to design anyway you want is much better solution so that we consumers can choose whatever our liking
If you sort my weight measurement in eyepiece focal length, it tells something: Some eyepiece weight is more than 10x than other with the same focal length.
Code:
Partial list where it is interesting:
grams F/L model name
237.0 16.0 WO-UWAN
84.0 16.0 ZAO2
722.0 17.0 TV-Ethos
179.0 19.0 TV-Panoptic
358.0 20.0 Pentax-XW
678.0 22.0 TV-Nagler
68.0 23.0 SV-Plossl
298.0 24.0 Hyperion
81.0 25.0 Zeiss-Ortho
75.0 28.0 Siebert-UW
958.0 28.0 WO-UWAN
771.0 30.0 BW-Optik/Zeiss
291.0 30.0 TMB-Paragon
160.0 30.0 Tak-LE
354.0 31.0 Hyperion
308.0 32.0 Edmunds-RKE
175.0 32.0 TV-Plossl
Tammy
Thanks for the data...it just supports what I am saying.
A 10x weight range is a sign of poor design in the industry.
A standardized weight would make for a better product.
A lighter weight would make for a better product.
And if they would design a doughnut that cause you to lose weight, life would be perfect. ;<)
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russell23
sage
Reged: 05/31/09
Posts: 423
Loc: Upstate NY
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What would be interesting to know for each eyepiece available out there is how much of the weight comes from the glass and how much from the housing - particularly for the really heavy eyepieces. Perhaps design of the housing and materials used could be adjusted to reduce the weights of some of these really heavy pieces.
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russell23
sage
Reged: 05/31/09
Posts: 423
Loc: Upstate NY
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Quote:
Doesn't this depend on whether the scope is balanced for a certain weight at a certain point? With my lightest eyepiece and the scope pointed near zenith, I have to dangle a counterweight from the UTA of my scope.
With a 31 nagler at the horizon, I have to add a 5lb counterweight to the mirror box.
There is NO weight that would be perfectly balanced near the zenith AND the horizon, so some form of counterweight will always be necessary unless the scope is so large the weight of the eyepiece is insignificant, or so "sticky" that the difference in the weight of eyepieces causes no noticeable balance changes.
I imagine it varies for mount type too. I use a williams optical EZ mount for my refractor. So all I have to do to balance the scope is adjust the position of the OTA in the rings so that with the altitude unlocked the tube assembly does not rotate up or down because of gravity. Once I've done that I am good to go.
The problem arises if I position the OTA with a really heavy or really light eyepiece and then I try to use one at the other extreme. That is why any of the 18+oz eyepieces won't work for me. If I bought one of them then I would have to re-adjust the tube in the rings when I switched to lighter eyepieces.
So every time I look at a possible eyepiece purchase I check the weight and the eyerelief because I wear eyeglasses. Those two criteria eliminate quite a few eyepieces for me.
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
What would be interesting to know for each eyepiece available out there is how much of the weight comes from the glass and how much from the housing - particularly for the really heavy eyepieces. Perhaps design of the housing and materials used could be adjusted to reduce the weights of some of these really heavy pieces.
My thoughts also.
The glass is the only important portion of the eyepiece...the rest is just support.
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
Quote:
Doesn't this depend on whether the scope is balanced for a certain weight at a certain point? With my lightest eyepiece and the scope pointed near zenith, I have to dangle a counterweight from the UTA of my scope.
With a 31 nagler at the horizon, I have to add a 5lb counterweight to the mirror box.
There is NO weight that would be perfectly balanced near the zenith AND the horizon, so some form of counterweight will always be necessary unless the scope is so large the weight of the eyepiece is insignificant, or so "sticky" that the difference in the weight of eyepieces causes no noticeable balance changes.
I imagine it varies for mount type too. I use a williams optical EZ mount for my refractor. So all I have to do to balance the scope is adjust the position of the OTA in the rings so that with the altitude unlocked the tube assembly does not rotate up or down because of gravity. Once I've done that I am good to go.
The problem arises if I position the OTA with a really heavy or really light eyepiece and then I try to use one at the other extreme. That is why any of the 18+oz eyepieces won't work for me. If I bought one of them then I would have to re-adjust the tube in the rings when I switched to lighter eyepieces.
So every time I look at a possible eyepiece purchase I check the weight and the eyerelief because I wear eyeglasses. Those two criteria eliminate quite a few eyepieces for me.
Agreed.
And if all your eyepieces were of the same weight, you would only have to adjust balance once.
And the lighter the eyepiece, the less impact it has on the mount and scope.
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 12221
Loc: Los Angeles
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Quote:
And if all your eyepieces were of the same weight, you would only have to adjust balance once.
Most dobs, even without an eyepiece, cannot be simultaneously balanced at both zenith and horizon.
So you cannot escape some form of dynamic balancing with most dobs. And if you are used to doing it, the weight of the eyepiece isn't important--it only determines the amount of weight.
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Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member
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Scott Watson
sage
Reged: 05/26/06
Posts: 279
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There are (at least) two reasons. First, because only high index materials perform "work" on light rays, any optical design code will have a tendency to fill the available working space with glass. It takes a great deal of skill to achieve an equivalent lens design without having nearly solid glass. The second reason is that high index materials are also (typically) high density materials. If plastic worked well, people would use it. It doesn't, and glass is the dominant material. A modern, 80+ degree FOV eyepiece suitable for use at f4 is really working the incoming light cone hard. To achieve good performance across the entire field is, frankly, a miracle. Weight and size are small prices to pay.
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Lawrence Sayre
Abbe Normal
Reged: 10/16/04
Posts: 4742
Loc: N.E. Ohio
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Quote:
Most dobs, even without an eyepiece, cannot be simultaneously balanced at both zenith and horizon.
So you cannot escape some form of dynamic balancing with most dobs. And if you are used to doing it, the weight of the eyepiece isn't important--it only determines the amount of weight.
True, but this (the spring and pulley system) helps:
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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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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
Quote:
And if all your eyepieces were of the same weight, you would only have to adjust balance once.
Most dobs, even without an eyepiece, cannot be simultaneously balanced at both zenith and horizon.
So you cannot escape some form of dynamic balancing with most dobs. And if you are used to doing it, the weight of the eyepiece isn't important--it only determines the amount of weight.
Is it not true that the amount of the weight affects the degree of balance?
The heavier the eyepiece, the more the imbalance is.
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
There are (at least) two reasons. First, because only high index materials perform "work" on light rays, any optical design code will have a tendency to fill the available working space with glass. It takes a great deal of skill to achieve an equivalent lens design without having nearly solid glass. The second reason is that high index materials are also (typically) high density materials. If plastic worked well, people would use it. It doesn't, and glass is the dominant material. A modern, 80+ degree FOV eyepiece suitable for use at f4 is really working the incoming light cone hard. To achieve good performance across the entire field is, frankly, a miracle. Weight and size are small prices to pay.
Scott...I said earlier that "glass is glass" and I understand that it might be needed...BUT the remainder of the eyepiece could easily be a lighter material.
Every ounce/gram matters.
But you raise an important point...glass is not the only optical material that could be used. Plastics are a possible alternative material.
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ColoHank
professor emeritus
Reged: 06/07/07
Posts: 515
Loc: western Colorado
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Quote:
The glass is the only important portion of the eyepiece...the rest is just support.
You don't really mean that, do you?
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Questar 3.5 standard - pyrex and BB coatings
Powerguide II
8mm, 12mm, 16mm, 24mm and 32mm Brandons
modified Bogen 3030 w/ homebuilt wedge
Homebuilt Galileo scope and very large and ugly homemade tripod
other odds and ends, including iPod Touch with StarMap Pro (what a marvelous combo)...
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"Nothing exists but atoms and empty space. Everything else is opinion."
Titus Lucretius Carus 99-55 B.C.
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 12221
Loc: Los Angeles
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Quote:
Quote:
Quote:
And if all your eyepieces were of the same weight, you would only have to adjust balance once.
Most dobs, even without an eyepiece, cannot be simultaneously balanced at both zenith and horizon.
So you cannot escape some form of dynamic balancing with most dobs. And if you are used to doing it, the weight of the eyepiece isn't important--it only determines the amount of weight.
Is it not true that the amount of the weight affects the degree of balance?
The heavier the eyepiece, the more the imbalance is.
The point I was making was that most dobs require some counterweight just to balance themselves. Adding an eyepiece merely changes the weight of the counterweight, not whether or not one is needed.
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Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
Quote:
Quote:
Quote:
And if all your eyepieces were of the same weight, you would only have to adjust balance once.
Most dobs, even without an eyepiece, cannot be simultaneously balanced at both zenith and horizon.
So you cannot escape some form of dynamic balancing with most dobs. And if you are used to doing it, the weight of the eyepiece isn't important--it only determines the amount of weight.
Is it not true that the amount of the weight affects the degree of balance?
The heavier the eyepiece, the more the imbalance is.
The point I was making was that most dobs require some counterweight just to balance themselves. Adding an eyepiece merely changes the weight of the counterweight, not whether or not one is needed.
This is not necessary true.
I have used dobs in the past that did not need counterweights once they were balanced initially.
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
Quote:
The glass is the only important portion of the eyepiece...the rest is just support.
You don't really mean that, do you?
Yes I do.
It is true.
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csa/montana
Wild Spirit
Reged: 05/14/05
Posts: 40206
Loc: montana
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Quote:
Quote:
Most dobs, even without an eyepiece, cannot be simultaneously balanced at both zenith and horizon.
So you cannot escape some form of dynamic balancing with most dobs. And if you are used to doing it, the weight of the eyepiece isn't important--it only determines the amount of weight.
True, but this (the spring and pulley system) helps:
Lawrence; that "spring & pulley system" looks pretty neat!
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Carol
AstroTech 16" Dob (Thanks ASTRONOMICS!)
Vixen 80MF/AstroTech Voyager
Masuyama's 7.5, 15, 25W, 35mm,
Pentaxes; 5XW, 7XL, 10XW.
14mm Meade 4000 UWA
TV Panoptics; 22, 35
DreamCatcher Dobservatory, #2
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 12221
Loc: Los Angeles
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Quote:
The point I was making was that most dobs require some counterweight just to balance themselves. Adding an eyepiece merely changes the weight of the counterweight, not whether or not one is needed.
This is not necessarily true.
I have used dobs in the past that did not need counterweights once they were balanced initially.
As have I.
But most dobs, if balanced perfectly at an altitude of 70-80 degrees will, if pointed at an altitude of 10 degrees, fall toward the ground. Or, if balanced for low altitude, will automatically rise if pointed up at 70-80 degrees.
That is, if the friction in the altitude bearings is very low. Sticky altitude bearings or very large heavy scopes don't react the same.
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Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member
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hfjacinto
Almost got me
Reged: 01/12/09
Posts: 2088
Loc: Union,NJ
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The issue with light eyepieces are IMO as follows:
1) People equate weight with quality
2) Carbon fiber is expensive, imagine what a carbon fiber ethos would cost.
3) The ep's need some type of structure to hold the glass in place, plastic can and will flex and ruin the performance of the EP.
4) Any light weight metal (such as titantium ) is very expensive.
5) Any new manufactoring of lightweight ep's will most certainly cost more than a heavy ep. I don't think many people will pay more for a light weight EP.
6) Durability - Steel is durable, it doesn't pit like Aluminun and is stable, any exotic material will need to measure up to steel before manufactors change over.
7) Any hint of a limit to usability will keep a product meant to be kept for a while as second teir.(if you think this is wrong, look at Plasma TV's, they were the first to market, but the mere mention that they only are good for 10,000 hours made LCD TV's the sales leader, are Plasma's better, yes in every test made my any consumer electronics magazine or reputable web page, but LCD outsells plasma 4 to 1)
Until these issues are resolved EP's will be heavy. Buy a go to mount and you won't have a problem with weight
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C9.25 ASGT 9*50 MM Finder,FT Focuser & 2" Diagonal
Meade LXD 75 6 Inch SNT w 9*50 MM Finder
5,6,9,14.5 MM Zhummel Planetary EPs
13,17,21,24,31,36 MM Baader Hyperion
6.7,8.8 MM Meade UWA & 11 MM Nagler T6
Planetary, OIII and Narrowband Filters
Thousand Oaks Dew Control w Kendrick Heaters
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NCMountains
scholastic sledgehammer
Reged: 01/02/09
Posts: 1131
Loc: NC- USA
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In all reagrds I like a EP built like a Sherman Tank! Call me American......but I like something built or at least feels like it is built to withstand a nuclear war! LMAO!
I would also assume it is a conspiracy with companies that build counterweight systems for our scopes! See where I am going with this......more money for vendors! But everything in my life is a conspiracy theory!
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CPC800 XLT SCT
Baader Hyperion EP's (8mm, 17mm, 24mm)& FTR's 14mm & 28mm; 40mm Celestron Plossl (came with scope) Vixen 30mm Plossl
GSO Barlow 2x; GSO 2" diagonal
UHC Nebula 1.25" filter
Orion solar filter
Orion StarShoot II CCD
Celestron Neximager (for solar system imaging)
Hirsch f6.3 focal reducer
Celestron SkyScout IYA2009
Mt. Pisgah Sky Chart:
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ColoHank
professor emeritus
Reged: 06/07/07
Posts: 515
Loc: western Colorado
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The glass is the only important portion of the eyepiece...the rest is just support.
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You don't really mean that, do you?
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Yes I do.
It is true.
Well then, perhaps you could tell me which is the only important component in a simple peanut butter sandwich: the peanut butter or the bread? Would you contend that the bread is just there for support?
While you're pondering these weighty questions, take apart your favorite eyepiece. Discard all of those heavy, bulky and unimportant metal parts and stack up only the essential glass elements on your diagonal.
Let us know how that works out...
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Questar 3.5 standard - pyrex and BB coatings
Powerguide II
8mm, 12mm, 16mm, 24mm and 32mm Brandons
modified Bogen 3030 w/ homebuilt wedge
Homebuilt Galileo scope and very large and ugly homemade tripod
other odds and ends, including iPod Touch with StarMap Pro (what a marvelous combo)...
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"Nothing exists but atoms and empty space. Everything else is opinion."
Titus Lucretius Carus 99-55 B.C.
Edited by ColoHank (07/05/09 11:32 AM)
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Lawrence Sayre
Abbe Normal
Reged: 10/16/04
Posts: 4742
Loc: N.E. Ohio
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Lawrence; that "spring & pulley system" looks pretty neat!
It works really well. It progressively provides more counterbalancing force as the scope is tilted more toward the horizon, which is exactly what is required to properly counterbalance a Dob.
I did not invent the idea. I saw it on the net a good number of years ago (perhaps 10), so the concept has been around for some time now. I want to say that the original idea belongs to David Knisley, but I am not 100% certain about that. I hope he is looking in so he can either confirm or correct me on this. I can't believe that every Truss Dob doesn't have a spring and pully counterbalance system by now, be it factory or homemade!
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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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Levine
sage
Reged: 03/24/06
Posts: 235
Loc: Indiana, Wabash County
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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?
In my experience, one of THE most Oink-worthy in this regard is the 40 mm cousin of the better known (and much lighter!) Leitz 88: the Rodenstock.
It is built like, and I believe FOR, a tank.
It tips the scales at 3.2 lbs!
See it here: http://www.cloudynights.com/item.php?item_id=327
    
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JMI NGT-18 f/4.5 GoTo Reflector, "Magellan"
C14/Homeyer Cradle f/11 XLT Fastar "Modoc"
C11 f/10 CFT XLT Fastar, "Dave"
CotoSKY 8.25" f/6 Achromat, "Blackjack"
Meade AR6 f/8 Achromat, "Kalliopi"
WO FLT 110 f/7 Apo, "Apollo"
Coronado PST f/10 "Icarus"
Canon IS 15 X 50 Binoculars
Losmandy G11/Gemini4
Discmounts DM-6, Sky Commander, StarBeam
Mallincam HPC/Watek monitor
Denk II Universal Power X Switch Binoviewer
Collins I3/Astronomik H-a/Starsweeper
...and some nice glass.
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 12221
Loc: Los Angeles
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Quote:
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Lawrence; that "spring & pulley system" looks pretty neat!
It works really well. It progressively provides more counterbalancing force as the scope is tilted more toward the horizon, which is exactly what is required to properly counterbalance a Dob.
I did not invent the idea. I saw it on the net a good number of years ago (perhaps 10), so the concept has been around for some time now. I want to say that the original idea belongs to David Knisley, but I am not 100% certain about that. I hope he is looking in so he can either confirm or correct me on this. I can't believe that every Truss Dob doesn't have a spring and pully counterbalance system by now, be it factory or homemade!
Alas, the spring idea can only work with one weight of eyepiece. If you have eyepieces that vary in weight, a counterweight will still have to be added to the spring.
But, with the spring, a fixed-position counterweight of a known size will work. That beats my system where the amount and position of the counterweight have to vary with eyepiece and direction of pointing.
I've also seen people hang a chain off the mirror box to accomplish the same thing as the spring--the lower the scope, the more chain is off the ground acting as counterweight.
The spring idea was well-described by Tom Krajci's article in November '99 S&T.
I think the idea is even older. Jim Phillips
contributed a program to calculate the various parameters that was on Mel Bartels' site for a while.
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Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member
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Mike Hosea
Post Laureate
Reged: 09/24/03
Posts: 3941
Loc: "Metrowest" Boston
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Well I know some eyepieces are gratuitously heavy. The short focal length Radians, for example, have heavy brass barrels that are bored out with holes just large enough for the optical path. In the longer focal lengths a lot of material must be removed to fit the light path, but in the shorter focal lengths the result is much like a bull-barrel on a handgun. I think it turns out for some odd reason that the 5mm Radian is the heaviest.
However, in typical the longer focal length eyepieces I think the OP may be over-optimistic about the relative weight of the housing. I don't recommend taking eyepieces apart, but this is one way to take the guesswork out of it. Most of the eyepieces I've taken apart have had 1.25" barrels, but some have been long focal length 2" eyepieces. I'd guess that, typically, the vast majority of the weight is in the optics. On average I think the density of glass and aluminum are comparable, but as the focal length gets longer, the amount of glass goes up proportionally to the cube of the focal length, whereas the amount of aluminum goes up proportional to the square of the focal length, and c*x^3 eventually beats d*x^2--and badly. In order to combat this issue, the designer probably must fix the optical design. There may be some wasted ounces in the housing, but by itself, making the housing lighter can't fix the problem if it never was the problem.
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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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Lawrence Sayre
Abbe Normal
Reged: 10/16/04
Posts: 4742
Loc: N.E. Ohio
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Thanks Don! You are absolutely correct, it was Tom Krajci who inspired the spring counterbalance system!
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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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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
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The glass is the only important portion of the eyepiece...the rest is just support.
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You don't really mean that, do you?
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Yes I do.
It is true.
Well then, perhaps you could tell me which is the only important component in a simple peanut butter sandwich: the peanut butter or the bread? Would you contend that the bread is just there for support?
While you're pondering these weighty questions, take apart your favorite eyepiece. Discard all of those heavy, bulky and unimportant metal parts and stack up only the essential glass elements on your diagonal.
Let us know how that works out...
It sounds like you are trying to pick a fight...if so go else where.
In your analogy of the peanut butter sandwich, I would be keeping the peanut butter (maybe going with the lite spread) and definitely go with a lighter weight bread instead of a heavier weight bread.
The result would be a better sandwich. ;<)
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russell23
sage
Reged: 05/31/09
Posts: 423
Loc: Upstate NY
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Quote:
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The glass is the only important portion of the eyepiece...the rest is just support.
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You don't really mean that, do you?
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Yes I do.
It is true.
Well then, perhaps you could tell me which is the only important component in a simple peanut butter sandwich: the peanut butter or the bread? Would you contend that the bread is just there for support?
While you're pondering these weighty questions, take apart your favorite eyepiece. Discard all of those heavy, bulky and unimportant metal parts and stack up only the essential glass elements on your diagonal.
Let us know how that works out...
It sounds like you are trying to pick a fight...if so go else where.
In your analogy of the peanut butter sandwich, I would be keeping the peanut butter (maybe going with the lite spread) and definitely go with a lighter weight bread instead of a heavier weight bread.
The result would be a better sandwich. ;<)
I don't think anybody is trying to pick a fight, but I think there is some frustration (speaking for myself at least) that you seem unwilling to provide some more substantive descriptions of where the weight of eyepieces has given you problems. Even an example would be helpful.
You mentioned you have several scopes earlier. Could you give an example of a specific telescope and specific eyepiece that in combination provide a problem due to the weight of the eyepiece?
With regards to your suggestion that all eyepieces are the same weight, I don't think that is realistic. Eyepieces are not designed for weight, they are designed for specific optical purposes and the weight is a byproduct of the manufacturers design. Change the weight and you change the design.
Nor are plastic lenses a realistic solution. If plastic was feasible as a high quality optical product we'd all be able to get great optics for very low cost.
I'm not unsympathetic to your concerns about weight. It limits which eyepieces I can purchase. But we have to be realistic too.
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
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Quote:
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The glass is the only important portion of the eyepiece...the rest is just support.
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You don't really mean that, do you?
--------------------------------------------------------------------------------
Yes I do.
It is true.
Well then, perhaps you could tell me which is the only important component in a simple peanut butter sandwich: the peanut butter or the bread? Would you contend that the bread is just there for support?
While you're pondering these weighty questions, take apart your favorite eyepiece. Discard all of those heavy, bulky and unimportant metal parts and stack up only the essential glass elements on your diagonal.
Let us know how that works out...
It sounds like you are trying to pick a fight...if so go else where.
In your analogy of the peanut butter sandwich, I would be keeping the peanut butter (maybe going with the lite spread) and definitely go with a lighter weight bread instead of a heavier weight bread.
The result would be a better sandwich. ;<)
I don't think anybody is trying to pick a fight, but I think there is some frustration (speaking for myself at least) that you seem unwilling to provide some more substantive descriptions of where the weight of eyepieces has given you problems. Even an example would be helpful.
You mentioned you have several scopes earlier. Could you give an example of a specific telescope and specific eyepiece that in combination provide a problem due to the weight of the eyepiece?
With regards to your suggestion that all eyepieces are the same weight, I don't think that is realistic. Eyepieces are not designed for weight, they are designed for specific optical purposes and the weight is a byproduct of the manufacturers design. Change the weight and you change the design.
Nor are plastic lenses a realistic solution. If plastic was feasible as a high quality optical product we'd all be able to get great optics for very low cost.
I'm not unsympathetic to your concerns about weight. It limits which eyepieces I can purchase. But we have to be realistic too.
Others have offered examples of specific eyepiece balance problems...there is no additional value for me to add more examples.
I am attempting to address the wider spread design problem because eyepieces are overweight.
Eyepieces could be lighter if the designers desired it as a design goal...and again others have already mentioned cases where weight savings could be implemented.
As for plastic, it is a viable optical quality material that is commonly used...most eyeglasses that we wear today are plastic lenses where they were glass years ago...mostly because of the weight and cost savings it offers.
Whether it is can be used depends on the optical design of the eyepiece in question. It already may be used...manufacturers would not be likely or willing to volunteer that information.
And as for using other lighter materials for the remaining components of the eyepiece, that is very possible and could easily be done.
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Lawrence Sayre
Abbe Normal
Reged: 10/16/04
Posts: 4742
Loc: N.E. Ohio
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Quote:
Alas, the spring idea can only work with one weight of eyepiece. If you have eyepieces that vary in weight, a counterweight will still have to be added to the spring.
Note that there are springs on both sides of the scope. If there is too much spring action (something I have yet to experience with either scope that I have this on) then the option is always available to simply unhook the spring from one of the two sides for the lightweight eyepieces, and then hook it back up for the heavy weight eyepieces. In my experience though it works fine with a fair range of eyepiece weights.
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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: 423
Loc: Upstate NY
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Quote:
Others have offered examples of specific eyepiece balance problems...there is no additional value for me to add more examples.
The value is in gaining some perspective on the types of problems you've encountered that are caused by eyepiece weight. I don't understand why it is so hard for you to be specific. When you asked me the same question I gave you specifics. But ok - I'll just have to continue in a fog of uncertainty as to why eyepiece weight is such a problem for you.
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I am attempting to address the wider spread design problem because eyepieces are overweight.
And here is why I keep asking you for specifics. I've asked several times now - at what point do the eyepieces become overweight 1oz, 2oz, 3oz, 4oz, 5oz, 6oz, 7oz ... 16oz ...24oz ... 35oz ... 100oz ...
If the problem is eyepiece weight, then you should try to specify a weight where the problem arises. And you should also try to define the nature of the problem caused by the weight.
Earlier I provided 3 examples of weight problems potentially associated with heavy eyepieces. That is another consideration when you talk about weight problems.
I don't know why I continue to ask you - nothing in the eyepiece industry is going to change because of our discussion.
Quote:
could be lighter if the designers desired it as a design goal...and again others have already mentioned cases where weight savings could be implemented.
The purpose of an eyepiece is to perform a specific optical goal. Obviously people are willing to buy a 31mm Nagler T5 weighing in at over 2 pounds, so the 35oz weight of the 31mm Nagler is not a problem for some people. It would be for me ... but many have equipment that can handle that eyepiece.
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As for plastic, it is a viable optical quality material that is commonly used...most eyeglasses that we wear today are plastic lenses where they were glass years ago...mostly because of the weight and cost savings it offers.
Sure, I wear glasses with plastic lenses - and the light weight is great compared with glass. But have you ever looked closely at plastic lenses after even 1 year of use. I clean my lenses with a cotton clothe only (as I was told I should do) and they still get scratched up.
Glasses are only supposed to last 1-2 years before they are replaced. Eyepieces are supposed to be designed to last forever. Plastic lenses simply will not do for that purpose.
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And as for using other lighter materials for the remaining components of the eyepiece, that is very possible and could easily be done.
But unless you are willing to provide a target weight it really doesn't matter. Do you want a 24oz 22mm Nagler T4 to be reduced to 16oz? 14oz? 12oz? 10oz? 8oz? ... Perhaps, using something like Gary Russell's Delrin plastic would help you achieve your target. But Delrin still has some weight and the glass isn't going to change. What do we do if it is not even possible to achieve that weight because the glass weight already exceeds what you're looking for?
Of course we don't even know what the target weight is.
Ok, I'm done. I've tried to make it clear why some specifics would help in this discussion. You'll do what you're going to do with that request.
Let's hope for some clear skies so we can observe instead of having free time to fritter away on this discussion.
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 12221
Loc: Los Angeles
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The question could be asked, "Why aren't eyepieces heavier?"
I'm sure I'm not alone in wishing that all eyepieces were 2" in diameter so I wouldn't have to use a (possibly misaligned) 1.25" adapter.
And it's annoying to have my scope perfectly balanced with a large 2" eyepiece only to have it be out of balance when switching to a smaller 1.25" one.
I don't think it's the weight that's the problem, but the lack of uniformity of the weights.
But picture the different demands:
1) I wear glasses and demand a lot of eye relief (think large eye lenses, here).
2) I don't wear glasses and I demand as few elements as possible (think small field of view and small size, here)
3) I demand an ultrawide field of view with no distortion (think many elements and larger cells).
4) I demand small sizes for binoviewing.
5) I demand ultrawide fields AND long eye relief.
6) I demand superb correction at the edge of a 100 degree field of view (think many elements and large lenses, here)
All those demands simply aren't compatible with the desire to make all the eyepieces small and light.
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.
If you had a "planetary set", they could all be fairly close in weight. If you had a set of large 2" ultrawide field eyepieces for DSO viewing, you could confine your choices to a fairly narrow range of weights. Ditto with widefields (e.g.Pentax XWs).
So the issue is being able to choose ANY eyepiece at ANY focal length and have them all balance equally. To do that, the manufacturers would have to add weight to the short focal lengths since the lenses in them are going to be smaller due to the laws of physics. If fact, you can buy a heavy brass 1.25" to 2" adapter to do just that type of balancing.
Of course, having them be all the same weight isn't going to matter to all scope users on all mounts, so the extra mass, and cost, added to the small focal lengths will be complained about ad nauseum.
It also depends on how big and heavy your scope is. The 60" at Mt. Wilson is heavy enough you can step off the ladder and stand with one foot on the scope to look through the eyepiece and it doesn't notice your weight! On that scope, every eyepiece made (including the huge 4" monsters they use for low powers) is a lightweight.
Ultimately, I don't think it matters much to the marketplace what the weights of eyepieces are unless they're too heavy for YOUR scope.
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Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member
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BillP
Post Laureate
Reged: 11/26/06
Posts: 3934
Loc: Vienna, VA
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I don't think the gas mileage is as good the heavier they are as they seem to stay parked in the case more. Hmmmm 
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Bill Paolini
XT10i Dob---TSA-102 S-APO---APM80/480 S-APO--- P.S.T.
TMB Supermonos---Meade UWAs---TV Panoptic---AT Titan II ED
To your own eyes be true...
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Quote:
Quote:
Alas, the spring idea can only work with one weight of eyepiece. If you have eyepieces that vary in weight, a counterweight will still have to be added to the spring.
Note that there are springs on both sides of the scope. If there is too much spring action (something I have yet to experience with either scope that I have this on) then the option is always available to simply unhook the spring from one of the two sides for the lightweight eyepieces, and then hook it back up for the heavy weight eyepieces. In my experience though it works fine with a fair range of eyepiece weights.
FWIW...I have seen users actually add weights to their eyepieces in the form of a collar so they all weight the same...so balance is done but once.
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Luigi
Post Laureate
Reged: 07/03/07
Posts: 4938
Loc: MA
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>>>And it's annoying to have my scope perfectly balanced with a large 2" eyepiece only to have it be out of balance when switching to a smaller 1.25" one.<<<
You need pargravitizing rings. These add weight to your lighter EPs to make them pargravitational with your heavier ones. The better ones are made of osmium, btw.
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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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Eddgie
Carpal Tunnel
Reged: 02/01/06
Posts: 2703
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This tread is rather dubious in terms of wheter any practical benefit or knolwedge will come from it.
Almost anything one can buy CAN be made lighter, but the market place drives what the designer does. If people refused to buy heavy eyepieces, then eyepieces would get lighter.
The market wants lighter more fuel efficient cars, and the US Auto Industry wasn't prepared for that market, so it failed.
But this was not always the case.. 4 years ago, people couldn't get ENOUGH big heavy SUVs.
But somehow, I don't think the same thing will happen with eyepieces. The weight savings of a few ounces by using carbon fiber for the eyepiece barrel is simply not going to sway any manufacturer to use it.
UNLESS... Some manufacturer introduces a line of carbon fiber barreled lightweight eyepieces and THEY SELL LIKE HOTCAKES! Then all of the other manufacturers will want a piece of their action and will add ultra-light eyepieces to their line.
Don't hold your breath though.
That being said, I hated the extra bulk of the Meade 18mm UWA I owned, so I sold it. It was just too gigantic for an 18mm 1.25" eyepiece. So I "GET" the issue in a way.
It is just not an issue that is going to change anytime soon most likely.
I think there is one company that sells eyepieces that use Delrin plastic for the barrels. Perhaps these are lighter (though I am not actuallly sure that they are, and my bet is that he uses plastic because it is far cheaper to machine and not necessarily because it weighs less).
Anyway, this is totally a markeing issue. Eyepieces COULD be lighgter, but until a substantial percentage of consumers start demanding this, they won't be.
Good luck with those windmills...
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Celestron C14, CGE (Big Al)
Astro-Physics 6" f/8 (Buffy)
Televue 101 (No name, but I call it my Widescreen HD Space TV)
The night sky is my mistress. She seduces me away from all other lovers.
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russell23
sage
Reged: 05/31/09
Posts: 423
Loc: Upstate NY
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Quote:
I think there is one company that sells eyepieces that use Delrin plastic for the barrels. Perhaps these are lighter (though I am not actuallly sure that they are, and my bet is that he uses plastic because it is far cheaper to machine and not necessarily because it weighs less).
The manufacturer is Gary Russell (no relation). I recently bought his 19mm 2" Konig. I originally planned to just compare the masses of the 19mm Russell Optics Konig to the 19mm Smart Astronomy EF (1.25") but I ended up getting more involved with this than I intended. So here goes:
When you mass different eyepieces you have to keep in mind that if you're using both 2" and 1.25" eyepieces the 2-1.25 adapter must be factored in. For my 2" diagonal, the 2-1.25 adapter has a mass of 85 grams.
So here is the breakdown of my eyepieces based upon mass. For 1.25 eyepieces I also provide the mass with the adapter:
24mm Brandon: 84g; 169g
19mm SA EF: 106g; 191g
24mm UO Konig: 124g; 209g
19mm RO 2" Konig: 151g
12.5mm Orion edge on: 153g; 238g
9mm Oriong edge on: 200g; 285g
32mm 2" UO Konig: 257g
27mm 2" TV Panoptic: 465g
Notice that with the Delrin plastic, the 2" 19mm Konig is actually the lightest eyepiece when the 2-1.25 adapter is factored in.
Next I decided to see how the different would influence the balance of my refractor in my Williams Optics EZ mount. So I set up the scope (120mm f/8.3 achromat) as I do when observing. Since I use the 32mm 2" Konig as a finder I decided to balance the scope in the rings with the 32mm Konig in the focused position. Now the 32mm Konig focuses with the focuser drawn out the most of any eyepiece in my collection.
So when I switched to the 19mm 2" RO Konig and adjusted to the focused position the objective end will drop if the altitude of the scope is below ~55 degree altitude. Switching to the 19mm EF, the scope maintains balance until the scope is lowered to only 30 degree altitude. Then I switched to the 12.5mm edge on which has a mass (with the adapter) only 19grams less than the 32mm Konig. With this small mass difference you can drop the scope to the horizon and it holds balance.
If I switch to the heavier 27mm Pan the scope's diagonal end drops to the ground.
Next I decided to balance the scope for my lightest eyepiece - the RO Konig. For this I found that when I switched to the 9mm edge, the 32mm Konig, and the 12.5mm edge on that the diagonal end drops quickly toward the ground. When I switch to the 24mm Konig which has a mass 58 grams more than the 19mm Konig the diagonal end dropped slowly to the ground. When I switched to the 19mm EF which is only 40 grams more massive than the 19mm Konig, the scope dropped very slowly but steadily to the ground. With the 24mm Brandon there was no noticeable drop.
I don't know if any of this is useful. It is one set of eyepieces with one specific mount. Obviously the "dropping" of the scope is not really a significant problem. I lock the altitude axis when switching eyepieces so that I don't bump the scope out of position. And when I adjust the scope's position my hands are on the tube, so again the weight difference is not a problem.
Anyway, I have a few more Russell-Optics eyepieces on the way, so I will let you know their masses when I get them.
Dave
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Eddgie
Carpal Tunnel
Reged: 02/01/06
Posts: 2703
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Ok, PERFECT.. The OP can buy Russel eyepieces with Delrin barrels is he wants the lightest weight eyepieces.
Whew. Glad we got to the bottom of THAT.
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Celestron C14, CGE (Big Al)
Astro-Physics 6" f/8 (Buffy)
Televue 101 (No name, but I call it my Widescreen HD Space TV)
The night sky is my mistress. She seduces me away from all other lovers.
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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Why do some posters turn so negative when discussing a simple design issue??
Lighter eyepieces would be a boon to amateurs.
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Jim Rosenstock
Post Laureate
Reged: 07/14/05
Posts: 3712
Loc: MD, south of the DC Nebula
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Quote:
Why do some posters turn so negative when discussing a simple design issue??
Perhaps they're not mature enough to scroll through four pages of pointless discussion without responding sarcastically. It's a common failing; you should pity them, Pal.
Quote:
Lighter eyepieces would be a boon to amateurs.
I bring a few helium balloons with me to my observing sessions, and tie them to my big Naglers. Works like a charm....
...and at the end of the session, I get to talk like Donald Duck!
Jim
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AlienFirstClass
professor emeritus
Reged: 02/13/09
Posts: 741
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LOL...good point.
Some people just aren't meant to design products.
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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: 4742
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: 423
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: 423
Loc: Upstate NY
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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).
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: 2755
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: 3941
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: 423
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: 423
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: 4938
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: 423
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
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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: 423
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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