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eyepieces/diagonals best suited to daytime terrestrial use with f13 127mm MAK?

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#1 DunninLA

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Posted 21 March 2019 - 07:19 PM

I am new to this, having just set up a Celestron Maksutov 127mm with 1.25" focuser in replacement of an 80mm ED spotting scope, which I sold yesterday.

 

I mostly view from my back deck, which is at 600' elevation an .6 miles from the ocean.   I look at ships, dolphins, and the beaches about 2-3 miles away to see what people are up to.

 

It seems this hobby has so many different expressions and pursuits, but mine is very narrow.  I am only concerned with eyepieces best suited to daytime view out to sea, and up the coast, using my f13 MAK.

 

I read this thread:  https://www.cloudyni...omparison-r2651  and came away with an appreciation for the different strengths an eyepiece may have in different circumstances.

 

Here are the attributes that I think, at this stage of early usage, I value:

- Longish eye relief as I wear glasses for mild astigmatism
- Center field sharpness.  I am not much concerned about outer 20% distortions
- High contrast / colors that pop
- wide field of view but only if other attributes listed here are not compromised.   I'm fine with 50*
- not expensive or rare

 

As you can see, I don't need to pay for ultra flat eyepieces whose claim to fame is clean focus at the periphery of the field of view in very fast scopes (e.g. $450 TV 24mm Panoptic).   My scope is very slow, and apparently also quite forgiving of eyepiece design.

 

With the MAK, I was supplied with a generic 25mm plossl of 52*, and a 9mm that yields an exit pupil of 0.7, which just doesn't work for daytime viewing.  I bought two eyepieces immediately to supplement or replace the 25mm -- the first is a 32mm 50* Celestron Omni ($40), and the second is the Explore Scientific 26mm 62* ($120).   This ES maxes out the usable FOV for 1.25" eyepieces.

 

I am also considering a Russell Optics 18mm 67* Japanese glass Konig eyepiece for bright, clear days.   For other than bright, clear days, I'm afraid the 1.4 exit pupil in my scope will be too dim for my purposes, and the 92x magnification would be too much for daytime atmospheric conditions.

 

After just reading the eyepiece article I reference above, I'm wondering if the 62* ES has compromised center focus sharpness to accommodate the wider fov.   Would the TV 25mm Plossl provide a better (per my wish list above), albeit narrower fov, view for me?

 

Diagonals:

As to 45* correct image prism diagonals, I have found five candidates I'd appreciate feedback on:

 

- Williams Optics ($80), with 25mm clear prism aperture  6 oz
- Orion, ($90), with 27mm clear prism aperture 6 oz
- Stellarvue ($69), with unknown clear prism aperture, unknown weight
- Baader, ($92), with 24mm clear prism aperture, 8.2oz
- Televue (discontinued, but still available) $60, unknown clear prism aperture, unknown weight

 

I already have the Celestron 45* ($30) diagonal and it appears people on this forum think this entry level 45* should normally be an upgrade candidate.   The way I use my scope... I sit in a deck chair with a Manfrotto clamp attached to on the right chair arm, and the center stem from my tripod into the clamp, and a Manfrotto video head.  I  swing the MAK so that the eyepiece rotates around to my eye.  The diagonal in this situation is sideways, parallel to the ground.  I don't set the diagonal up perpendicular to the ground and look down into it.

I am assuming that all 90* diagonals will rotate the image as I rotate the diagonal?   That's what happens with the star 90* diagonal that came with the scope.   I ask that because I read good comments about a 60* televue diagonal, but also assume the image won't orient correctly for me when I rotate the diagonal to be parallel to the ground?

 

Thanks for the help.


Edited by DunninLA, 21 March 2019 - 07:36 PM.


#2 Lt 26

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Posted 21 March 2019 - 08:16 PM

My choice is a TV 20mm plossl in a TV 60° diagonal. This combo transforms my TV102 into the 880 Yardmaster.

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#3 DunninLA

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Posted 21 March 2019 - 08:28 PM

My choice is a TV 20mm plossl in a TV 60° diagonal. This combo transforms my TV102 into the 880 Yardmaster.

Dereck

Dereck, does the TV 60* diagonal image maintain its vertical orientation when rotating the diagonal sideways?


Edited by DunninLA, 21 March 2019 - 09:05 PM.


#4 DunninLA

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Posted 21 March 2019 - 08:59 PM

I found an a propos post on another forum through googling.   

 

If this is correct then I'd rather not give up the extra FOV the ES 26mm 62* offers vs. the TV 25mm plossl at 50*.  I note as well the eye relief on the TV is 17, whereas it is 19.2 on the ES... but ER tricky and one mfr. will measure from the lens apex, another from the eyecup at its shallowest setting.

 

 

 

If they're on slow f/ratio scopes (SCT's, Mak's, et cetera), even if I compare an ES to a TV one right after the other I can't pick out a difference.

Edited by DunninLA, 21 March 2019 - 09:04 PM.


#5 silv

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Posted 22 March 2019 - 02:26 PM

 

I'm wondering if the 62* ES has compromised center focus sharpness to accommodate the wider fov.   Would the TV 25mm Plossl provide a better (per my wish list above), albeit narrower fov, view for me?

from a recent thread: https://www.cloudyni...p/#entry9209517

"Pros:  nice eye relief, extremely comfortable eyepiece to view thru.  Cons: not sharp at the field edge, while the view is very nice at field center, stars become astigmatic as you move your eye toward the field edge.  15% or so out from the edge the stars are not sharp/pinpoint."

 

with 20mm eye relief and 2.2mm exit pupil they do sound good for looking at your beach 2 miles away, rain or shine. I haven't used them or any ES in my fast refractor, though. 

The wider FOV compared to the TV plossl is not to be underestimated, even when stars or beach balls at the edge aren't pin points.

The image impression in a wider field (not too wide, though) when looking at the centre which has a visible surrounding area  is more natural. It's what our brain/eye does all the time: focus on 1 object and also register the stuff around it, even let the pupils wander a bit without them suddenly hitting a "wall". The more natural you can get in your viewing setup, especially in daylight when your brain expects what it is most used to, the better the overall experience. 

 

 

I ask that because I read good comments about a 60* televue diagonal, but also assume the image won't orient correctly for me when I rotate the diagonal to be parallel to the ground?

I don't know. Hopefully someone else chips in. 

 

I like how you described your magic arm do-up. Took me a while to picture it. Sounds comfy! Mind posting a picture with scope, magic arm, chair and view? 


Edited by silv, 22 March 2019 - 02:30 PM.


#6 Starman1

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Posted 22 March 2019 - 02:40 PM

I am new to this, having just set up a Celestron Maksutov 127mm with 1.25" focuser in replacement of an 80mm ED spotting scope, which I sold yesterday.

 

I mostly view from my back deck, which is at 600' elevation an .6 miles from the ocean.   I look at ships, dolphins, and the beaches about 2-3 miles away to see what people are up to.

 

It seems this hobby has so many different expressions and pursuits, but mine is very narrow.  I am only concerned with eyepieces best suited to daytime view out to sea, and up the coast, using my f13 MAK.

 

I read this thread:  https://www.cloudyni...omparison-r2651  and came away with an appreciation for the different strengths an eyepiece may have in different circumstances.

 

Here are the attributes that I think, at this stage of early usage, I value:

- Longish eye relief as I wear glasses for mild astigmatism
- Center field sharpness.  I am not much concerned about outer 20% distortions
- High contrast / colors that pop
- wide field of view but only if other attributes listed here are not compromised.   I'm fine with 50*
- not expensive or rare

 

As you can see, I don't need to pay for ultra flat eyepieces whose claim to fame is clean focus at the periphery of the field of view in very fast scopes (e.g. $450 TV 24mm Panoptic).   My scope is very slow, and apparently also quite forgiving of eyepiece design.

 

With the MAK, I was supplied with a generic 25mm plossl of 52*, and a 9mm that yields an exit pupil of 0.7, which just doesn't work for daytime viewing.  I bought two eyepieces immediately to supplement or replace the 25mm -- the first is a 32mm 50* Celestron Omni ($40), and the second is the Explore Scientific 26mm 62* ($120).   This ES maxes out the usable FOV for 1.25" eyepieces.

 

I am also considering a Russell Optics 18mm 67* Japanese glass Konig eyepiece for bright, clear days.   For other than bright, clear days, I'm afraid the 1.4 exit pupil in my scope will be too dim for my purposes, and the 92x magnification would be too much for daytime atmospheric conditions.

 

After just reading the eyepiece article I reference above, I'm wondering if the 62* ES has compromised center focus sharpness to accommodate the wider fov.   Would the TV 25mm Plossl provide a better (per my wish list above), albeit narrower fov, view for me?

 

Diagonals:

As to 45* correct image prism diagonals, I have found five candidates I'd appreciate feedback on:

 

- Williams Optics ($80), with 25mm clear prism aperture  6 oz
- Orion, ($90), with 27mm clear prism aperture 6 oz
- Stellarvue ($69), with unknown clear prism aperture, unknown weight
- Baader, ($92), with 24mm clear prism aperture, 8.2oz
- Televue (discontinued, but still available) $60, unknown clear prism aperture, unknown weight

 

I already have the Celestron 45* ($30) diagonal and it appears people on this forum think this entry level 45* should normally be an upgrade candidate.   The way I use my scope... I sit in a deck chair with a Manfrotto clamp attached to on the right chair arm, and the center stem from my tripod into the clamp, and a Manfrotto video head.  I  swing the MAK so that the eyepiece rotates around to my eye.  The diagonal in this situation is sideways, parallel to the ground.  I don't set the diagonal up perpendicular to the ground and look down into it.

I am assuming that all 90* diagonals will rotate the image as I rotate the diagonal?   That's what happens with the star 90* diagonal that came with the scope.   I ask that because I read good comments about a 60* televue diagonal, but also assume the image won't orient correctly for me when I rotate the diagonal to be parallel to the ground?

 

Thanks for the help.

A correct image diagonal and as low a power as is practicable.

Normal daytime magnifications are 20-60x, but you'd need eyepieces from 77mm down to 26mm to accomplish that.

And if the exit pupil gets larger than your eye (maybe 3mm in the daytime, for a 39mm eyepiece), the shadow of the secondary becomes obtrusive.

That's one reason nearly all daytime scopes are refractors.

So figure you'll use eyepieces from about 25mm to 40mm for nearly all your observing, with emphasis on the 40mm.

Go with a good 40mm Plössl for a lowest power eyepiece, and then get a 25mm 60° or a 24mm 68° eyepiece for the second one.

All 3 would see about the same true field area, but at different magnifications.



#7 DunninLA

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Posted 22 March 2019 - 03:23 PM

- A correct image diagonal and as low a power as is practicable.

 

- get a 25mm 60° or a 24mm 68° eyepiece for the second one.

 

 

Old Hippie,

 

1. Do you have any recommendation regarding the 5 45* correct image diagonals I listed?

 

2. you carry all three of these... which would you recommend:

 

- TV plossl 25mm 50*

- ES 26mm 62*

- ES 24mm 68*  (the reason I didn't mention this earlier is that i didn't want to get below 25mm due to exit pupil getting smaller.



#8 Starman1

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Posted 22 March 2019 - 04:27 PM

I think you'd enjoy the 68° field a lot in the daytime, though 62° is OK, too.

Make sure the Orion you're looking at is the Deluxe one.

I didn't remember the TeleVue 45° one, but it looks like the one you already have, so one of the other 4 would be recommended.

The StellarVue has a 25mm clear aperture and is the cheapest.

I would not be surprised if all of them were from the same Chinese source, but they'd all be fine.



#9 DunninLA

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Posted 22 March 2019 - 04:46 PM

1. I think you'd enjoy the 68° field a lot in the daytime, though 62° is OK, too.

 

2. The StellarVue has a 25mm clear aperture and is the cheapest.

 

Old Hippie,

 

1. I was really debating whether I'd want the 68* FOV, or the extra exit pupil...plus the 62 is about $40 cheaper.  The real issue there is that I've been using the 25mm 52* plossl, the $15 one that came with the scope (which sucks compared to the 32mm... dull, fuzzy), and a 32mm Celestron Omni 50* ($40), and I don't really wish I had a larger FOV.   If anything, I pan with my video head, find something to look at that's 1.6 miles away (minimum) -- ship at sea, people climbing rocks at the beach, etc, and the FOV at thae 1.6 mile distance seems like it's  about 40 or 50 yards, and I only really look at the center 20% - 25% of the FOV.   I'm not sure what I'd do with more FOV since I'm not tracking birds in flight, or really anything moving fast.   That's why I was wondering if the Televue 25mm 50* plossl would be better, but only if the optics are superior to the ES, since FOV may not be high on my priority list.   And by optics I mean only the center 60% of the FOV... I'm not concerned with distortion on the periphery.

 

2. If the StellarVue is 25mm prism clear aperture, then its for sure the Williams in another costume, inasmuch as they look identical on the outside including the brass compression ring.   Where did you get that stat?   It isn't on stellarvue's website, not is it in any retailers description.   You obviously have your ways smile.gif


Edited by DunninLA, 22 March 2019 - 04:55 PM.


#10 Starman1

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Posted 22 March 2019 - 07:16 PM

Look here under Product Description: https://www.stellarv...ism-1-25-d1032/

And you're probably right it's the same as the WO.

 

The wider field means objects get picked up by the scope as they enter the field a lot faster.

That's important in birding.

Your 25mm Plössl should be equally as sharp as the 32mm, so it's definitely time to change eyepieces.



#11 DunninLA

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Posted 22 March 2019 - 09:09 PM

Old Hippie,

 

Thanks.  I tried the ES 62* 26mm today, and I think I'm learning that exit pupil is pretty critical to me.  I much preferred the view with the Celestron Omni 32mm 50*.  What!!!  How can that be.

 

Well, I was able to resolve details better with the 32mm, and colors were more saturated.  That is opposite to what I expected, but I've concluded that my aging eyes need more light.   Exit pupil on the 32mm is 2.5.   Exit pupil on the 26mm is 2.0.   So even though the 26mm gave me 64x magnification, vs. the 52x of the 32mm, on a full sun day with no heat mirage b/c I'm viewing over water and better than average viewing,  I was able to pick out, from a group of people on a rock 1.8 miles away, that there were maybe 3 or 4 people with the 26mm ES, but definitely could identify four distinct individuals with the 32mm.   It just seemed more in sharp focus.

 

Then at 6:45 in waning light, looking at the same beach, I could get better detail with the 32mm than I could with the 26mm.  The 32mm for my eyes was brighter, sharper, and more color saturated.    A crummy $40 eyepiece served me better than a $120 well regarded eyepiece.   

 

I think I had better stick with 32mm and above eyepieces.   Going to greater magnification actually allows me to see less, so I think my eyes need at least 2.5 exit pupil, or maybe 2.25, but definitely more than 2.

 

The only thing that might allow me to get slightly higher magnification (slightly smaller exit pupil) is if a higher quality 45* correct image prism diagonal transmits more light than the Celestron I currently have installed.


Edited by DunninLA, 22 March 2019 - 09:17 PM.


#12 Starman1

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Posted 22 March 2019 - 11:19 PM

Old Hippie,

Thanks. I tried the ES 62* 26mm today, and I think I'm learning that exit pupil is pretty critical to me. I much preferred the view with the Celestron Omni 32mm 50*. What!!! How can that be.

Well, I was able to resolve details better with the 32mm, and colors were more saturated. That is opposite to what I expected, but I've concluded that my aging eyes need more light. Exit pupil on the 32mm is 2.5. Exit pupil on the 26mm is 2.0. So even though the 26mm gave me 64x magnification, vs. the 52x of the 32mm, on a full sun day with no heat mirage b/c I'm viewing over water and better than average viewing, I was able to pick out, from a group of people on a rock 1.8 miles away, that there were maybe 3 or 4 people with the 26mm ES, but definitely could identify four distinct individuals with the 32mm. It just seemed more in sharp focus.

Then at 6:45 in waning light, looking at the same beach, I could get better detail with the 32mm than I could with the 26mm. The 32mm for my eyes was brighter, sharper, and more color saturated. A crummy $40 eyepiece served me better than a $120 well regarded eyepiece.

I think I had better stick with 32mm and above eyepieces. Going to greater magnification actually allows me to see less, so I think my eyes need at least 2.5 exit pupil, or maybe 2.25, but definitely more than 2.

The only thing that might allow me to get slightly higher magnification (slightly smaller exit pupil) is if a higher quality 45* correct image prism diagonal transmits more light than the Celestron I currently have installed.

Remember that most daylight spotting scopes only go up to 45 to 60x. It's a matter of light and the fact the daytime atmosphere is never as steady as the night air.

#13 AxelB

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Posted 23 March 2019 - 10:18 PM

The 32mm Omni plossl is surprisingly good for its price.

If you like it and would just sometimes like more magnification, why not buy another shorter Omni ? If you really need the eyerelief, you could also get a x2 barlow and use it with your existing eyepieces. The Celestron X-cel is good and not too expensive.

My advice is dont waste money on Televue plossl. For your scope and its main usage, the Omni line is plenty enough.

If you ever want to observe without glasses, you can correct astigmatism with a Televue Dioptrx. To fix one on a 32mm Omni you’ll need the DEA-0001 adapter.

Edited by AxelB, 23 March 2019 - 10:22 PM.


#14 MartinPond

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Posted 23 March 2019 - 10:36 PM

Remember that most daylight spotting scopes only go up to 45 to 60x. It's a matter of light and the fact the daytime atmosphere is never as steady as the night air.

You got that straight!

Past 1/4 mile, horizontal seeing leaves you with 35x to 65x(perfect light breeze, over-ocean, condensing).

 

Bear in mind....at 100 yds or less, you can pump the power up more on a good day..

Beaver dams and bluebird boxes, turkeys in trees, birdfeeders, etc..


Edited by MartinPond, 23 March 2019 - 10:37 PM.


#15 DunninLA

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Posted 24 March 2019 - 07:03 PM

My advice is dont waste money on Televue plossl. For your scope and its main usage, the Omni line is plenty enough.
\

NOW you tell me.   Bought from Classifieds a 32mm TV plossl last night.   But easy enough to flog it on if, as another poster (possibly you) wrote, the TV is slightly warmer in tone and no better optically than the Omni.  My scope is so slow that I don't need the edge correcting design of the TV.

 

I'm not sure viewing through a 32mm wouldn't be worse without glasses.   The eye relief is so long that my view is just right with rubber cups extended and my glasses resting on the cups.


Edited by DunninLA, 24 March 2019 - 07:06 PM.


#16 DunninLA

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Posted 24 March 2019 - 09:19 PM

AxelB:   I thought you'd be interested to know that upon google searching, I found a post on another website extolling the virtues of the Celestron Omni 32mm plossl.

 

https://stargazerslo...-plossl/page/2/

 

Check the fourth post down, where he does a nice comparision between the Omni, the GSO, and the Meade 4000, all  32mm

 

This is not the only post I found indicating the exemplary brightness of the view through the Omni.   At any rate on Thursday this week I'll have the TV in my hands, and will post my impressions, for daytime only viewing.


Edited by DunninLA, 24 March 2019 - 09:21 PM.


#17 coopman

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Posted 25 March 2019 - 03:02 PM

I have the WO 45 deg. erecting prism and used it with an 80ED refractor before I sold that scope.  I was pleased with the terrestrial views that I got at ~20X. 


Edited by coopman, 25 March 2019 - 03:03 PM.


#18 DunninLA

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Posted 25 March 2019 - 04:08 PM

I have the WO 45 deg. erecting prism and used it with an 80ED refractor before I sold that scope.  I was pleased with the terrestrial views that I got at ~20X. 

thanks, that's what I'll order then.   If I can't notice any difference vs. the $30 celestron erecting prism I have installed now, I'll simply send it back.


Edited by DunninLA, 25 March 2019 - 04:10 PM.


#19 DunninLA

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Posted 25 March 2019 - 04:15 PM

today tried the Celestron Xcel and Meade HD 60 25mm eyepieces, in comparison to the ES 26mm 62* eyepiece.

 

in my f13 Mak, they are all virtually the same.   I prefer the twist up eyecup of the Xcel for my glasses, but other than that they all are about equally bright, equally sharp, equal color rendition, similar sharpness at the edge of field.  In a slow scope, the ES certainly isn't worth almost twice the Xcel or HD60, since it performs identically .

 

And I'm keeping none of them.   There is no point to increased mangification if it doesn't allow me to see any more detail.   So I'll just keep the cheepie 32mm Omni, unless the TV coming Thursday is better.   From what I've read now, given my f13 scope, the Omni with its cooler color tone may actually, to me, turn out to be superior.



#20 Starman1

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Posted 25 March 2019 - 05:03 PM

32mm to 25-26mm isn't enough of a change to matter.

The next eyepiece following the 32mm should be a 20-21mm.



#21 DunninLA

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Posted 25 March 2019 - 06:47 PM

Old Hippie,

 

I went to your website to order the Williams 45* correct image diagonal... but it appears you don't carry that one.   So I will order from another place.   I did see you carry ES and Tele Vue.

 

The 25mm would have been useful if I could have read a sign, or seen some detail of the beach or a boat, I could  not see with the 32mm.   But I could not.   I tried many times with the Xcel, HD60, and ES.  I chalk that up to atmospheric interference.

 

As to 20mm, I think I'm just going to live with the limitations imposed by daytime atmosphere and stick with 52x magnification, which for my 1650 MAK is 32mm.   If even 64x (25mm) does not show me additional detail, and I lose contrast, brightness, and color saturation, how much worse would it be at 83x (20mm)?   I think its a lost cause. for 90% of the days of the year.

 

Actually I am quite satisfied with 52x.  At 1.6 miles I can see the beach, see people well enough to know if male or female, adult or child, the pattern of their clothing, and see them climbing on the rocks at the shore.    I can see the kids playing basketball well enough to know when they're dribbling, and when shooting, though I can't see the basketball itself.   I can see a pleasure boat 1200 yards away enough to make out its name, how many people are on board, and how many people jump off the back to go scuba diving.    And I can almost make out the particular features of their faces. 

 

Maybe 15 or 20 days a year an 83x (20mm) would be useful when the air is crystal clear. of particulates, and the temperature in the air is the same as ground/sea temperature.. so I'll still have to think about having an eyepiece for use just a few days per year.


Edited by DunninLA, 25 March 2019 - 07:02 PM.


#22 Starman1

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Posted 25 March 2019 - 10:12 PM

or use a low power Barlow. Many 2x Barlow lenses separate from their holders and thread directly onto the eyepiece, yielding a 1.5-1.6x magnification. Might be cheaper than an eyepiece and usable with multiple eyepieces.


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