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World's Biggest/Heaviest EP?

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#26 Lew Zealand

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Posted 19 August 2013 - 05:17 PM

The final addendum to all this is that the 25mm ES100 has enough ER to use with glasses on, unlike all other 100° EPs available today. So that choice made a few years ago may not matter in the long run as that ES ep may replace the 31mm 82°. But then look at the price, same as the Nagler…


Well, this depends a lot on:
how deep-set your eyes are,
how close to your eye the lenses of your glasses are,
and how much pressure you want to exert on your glasses when you look through the eyepiece.

It's why some people find 12-14mm enough eye relief for glasses, while others find 20mm to be barely enough.

When I tested the 25x100, I did not find its eye relief sufficient for me to see the edges of the field, even with peripheral vision, while wearing glasses, and I wear thin lenses close to my eyes. I was not, however, willing to grind my expensive glasses against the top of the eyepiece.

The rated eye relief of the 25x100 is 14.5mm, while the "effective eye relief" (the distance from the top of the eyepiece to the exit pupil) is actually about 2mm to 3mm less.

Personally, I find an "effective" eye relief of about 17-18mm to be the minimum I can tolerate with glasses on.

It's great you can see the entire field with glasses on, but I suspect very few glasses wearers would be able to.


I'd like to quote your whole response as it's spot on but emphasize the green highlighted portion. I don't mind mashing my glasses a bit and yes, this is necessary on the 25 ES100 and many other widefield, low power EPs I use. To be frank, I couldn't tell you how much of this I do with any of the Meade 5Ks, 31AX, or the 31mm Nagler when I tested it. I'm so used to doing that that it hasn't been an issue for me. Clearly though, a number of people are not going to be satisfied with that.

The take home of that for me is that I really did have a problem with the Meade and ES 30mms, even with mashing, as well as the 24 Pan and a number of other EPs. And I suppose I have reasonably well-mounted scopes (a concern of mine from the start) as that kind of viewing will induce shakes in unstable scopes.

#27 Usquebae

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Posted 19 August 2013 - 07:21 PM

Mashing?!?

After all the pains I've taken (and paranoia I've suffered) in learning the ultra-delicate art of cleaning (my cheapo) EP lenses, now I hear that people routinely grind their spectacles against ES 100s! If the slightest hint of grit on a gently swabbed EP will scratch it, what is all this glass-on-glass violence going to do? I guess one should be careful not to buy used from eyeglass gazers.

:john:

#28 Scanning4Comets

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Posted 19 August 2013 - 07:25 PM

Bangers and Mash!!! :roflmao:

#29 Usquebae

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Posted 19 August 2013 - 07:29 PM

That 31mm Axiom is impressive. I've been on the fence about which max-FOV piece to buy. Has it been determined whether the Luminos 31mm is identical to the Axiom? And does the Luminos also come with a can of ham? If so, I'm sold.

#30 Pinbout

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Posted 19 August 2013 - 09:33 PM

here at the end you can look thru it.

http://www.youtube.c...h?v=6aoE5MUch1Y

:grin:

#31 WesC

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Posted 20 August 2013 - 01:57 AM

How about that 30mm ES100 with the 3" barrel? That's a monster.

#32 Scanning4Comets

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Posted 20 August 2013 - 03:12 AM

MrPinbout,

That sure looks huge, :bigshock:

#33 cjc

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Posted 20 August 2013 - 03:46 AM

Well, this depends a lot on:
how deep-set your eyes are,
how close to your eye the lenses of your glasses are,
and how much pressure you want to exert on your glasses when you look through the eyepiece.

It's why some people find 12-14mm enough eye relief for glasses, while others find 20mm to be barely enough.

When I tested the 25x100, I did not find its eye relief sufficient for me to see the edges of the field, even with peripheral vision, while wearing glasses, and I wear thin lenses close to my eyes. I was not, however, willing to grind my expensive glasses against the top of the eyepiece.

The rated eye relief of the 25x100 is 14.5mm, while the "effective eye relief" (the distance from the top of the eyepiece to the exit pupil) is actually about 2mm to 3mm less.

Personally, I find an "effective" eye relief of about 17-18mm to be the minimum I can tolerate with glasses on.

It's great you can see the entire field with glasses on, but I suspect very few glasses wearers would be able to.


Can I add to this list:

how close fitting your spectacles are;

whether you have basic long-sight or short-sight correction (in the latter case the lens acts as a mild barlow extending the effective eye relief);

how much your pupil dilates in the dark (which allows the eye to be drawn back from the the quoted eye relief distance without the view being vignetted);

the exit pupil of the particular eyepiece scope combination (a smaller exit pupil again allows the eye to be taken further back.

The most important point to note is that people wearing spectacles are different and the guidance on which eyepieces might be usable is only that: guidance. It is very worthwhile trying for yourself!

#34 csrlice12

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Posted 20 August 2013 - 07:51 AM

As far as not seeing the edge of the fov with the 100* series eyepieces (any brand)......that's kinda the idea.....it's about NOT seeing the edge of the fov, it's a more "natural" view.

#35 Joe Ogiba

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Posted 20 August 2013 - 08:06 AM

Pentax XL 60mm


1. Technical Specifications

- Focal lenght 60 mm
- FOV 65°
- Fieldstop diameter 72 mm
- Diameter lens eyeside 65 mm
- 5 elements in 4 groups, fully SMC multicoated
- Eyerelief from 10 mm to 44.4 mm
- Weight 1.650 gramm
- Instead of barrel it comes with M84x1 thread
- Inside the bottom side it have a M77x0.75 filterthread
- lenght 253 mm
- Upper diameter 84 mm
- Partial rubberamored housing

2. Description

The eyepiece is made from CNC maschined black anadized aluminium body. The lenses are fixed in the upper 1/3 part of the housing surrounded by the movable eyeguard, with which you can search your best eyerelief, changable from 10 mm to 20 mm. The 44.4 mm is the distance from eyelens to focus. With this movable eyeguard you have the possibílity to find the most comfortable eyerelief for yourself. Works similar to the movable eyeguard on the XL 40 mm.

The upper part has an outer rubber ring to hold the eyepiece safety in your hand. On the lower part just above the connection thread is another rubber ring. I expect that this eyepiece is made that long to be used straight through in the larger 8" and 10" Pentax Apos. For myself I would cut the eyepiecetube for at least 100 mm less lenght and would attach an adapter for a 3" Stardiagonal. With the original contruction it requires lots of backfocus on your scope.

3. Impressions

I used this eyepiece straight on my Zeiss Semi-Apochromat AS 130/1950 on which is provides a 32,5 power and an exit pupil diameter of 4 mm, just the right size. The field of view I am getting with this eyepiece on this telescope is about 2.1 degree. I used the eyepiece now on diffrent daytime objects, in nighttime I watched a birght traffic light and between the clouds some stars.

At daytime it provides razor sharp images up to the fieldstop without any kind of lateral color. I did not notice that little yellow touch of false color I see always in the shorter XL eyepieces. Watching at night the bright traffic light and moving it through the field i could not see any ghostimages, thanks to the famous Pentax SMC coatings, I expect. Looking between the clouds to the sky, they daytime observing was repeatable, stars in my scope are pinpoint to the fieldstop. Kidnebean effects have been totaly absense on daytime as well as on nighttime.

4. Price

It is the most expensive eyepiece I ever heard about, US $ 3,900 plus shipping. If the eyepiece would run in the range up to US $ 1,500 I am pretty shure i would buy it, but $ 3,900 , outch; this is even for me a little too much.

http://www.cloudynig...php?item_id=320


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