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Does anybody have experience with this or shall I be the guinea pig?

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#1 Ben the Ignorant

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Posted 09 May 2021 - 08:02 AM

A 32mm eyepiece with an 82° field would yield 25x and 3°17' with my 115mm/805mm triplet. The exit pupil would be 4.6mm across, very good and nearly the maximal practical size. The 3 degrees-plus viewing window would qualify as rich-field and the same scope can do high power on planets, so here I am with a do-everything scope.

 

My apo is currently linked to a 34mm/68° eyepiece that's fine but it really belongs to a smaller f/7 semi-apo doublet, and true to the triplet 115's superiority, it deserves an 82° ocular. I absolutely refuse to waste usable field so the 82° spec seemed like a must.

 

Well, searching the vendors, I found a 32mm/82° that's ideal on paper, especially with its 199€ price; my expense limit on eyepieces is precisely 200€. My reasoning is, the thing is modern, got out only a few years ago, so the optical design must be good, 82° optics technology is about 40 years old and became affordable long ago, the flaws of previous generations should be debunked by now.

 

https://www.astrosho...ab_bar_2_select

 

oberon 32.png

 

The weight is an impressive 947 grams, 100 more than my heaviest eyepiece but the 115's focuser is very strong and accurate, so no big worries about that. Multicoatings and complete blackening are standard in that class, so no worries either there. The only question is, how good is it?

 

Resolution at the center is always important but it's not the top priority in a gigantic true field, ultralow power eyepiece. The number one criteria will be edge performance because the objective's field and the eyepiece's field are both maximal and we know the edge is always where the results disappoint or not in widefield observing.

 

The question was asked in other forums but the answers consisted of beating around the bush, no a single straight one. So, does a Cloudy Nights member know and is willing to share, or shall I be the guinea pig?


Edited by Ben the Ignorant, 09 May 2021 - 03:22 PM.


#2 luxo II

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Posted 09 May 2021 - 08:16 AM

The weight is an impressive 947 grams, 

 

...shall I be the guinea pig?

Haven't heard of this one before, and most likely it's something else rebranded (the Chinese factories will slap any resellers name on if you buy a few dozen wholesale). 

 

Weight doesn't translate into optical quality - I've seen handgrenades shamed by little eyepieces, and hand grenades that turn out to be a large metal shell with a rather ordinary eyepiece inside (yes Vixen, I mean you).

 

 

... looks like you're going to be the guinea pig, unless someone spots what the mainstream brand was.


Edited by luxo II, 09 May 2021 - 08:16 AM.

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#3 Miranda2525

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Posted 09 May 2021 - 08:46 AM

A 32mm eyepiece with an 82° field would yield 25x and 3°17' with my 115mm/805mm triplet. The exit pupil would be 4.6mm across, very good and nearly the maximal practical size. The 3 degrees-plus viewing window would qualify as rich-field and the same scope can do high power on planets, so here I am with a do-everything scope.

 

My apo is currently linked to a 34mm/68° eyepiece that's fine but it really belongs to a smaller f/7 semi-apo doublet, and true to the triplet 115's superiority, it deserves an 82° ocular. I absolutely refuse to waste usable field so the 82° spec seemed like a must.

 

Well, searching the vendors, I found a 32mm/82° that's ideal on paper, especially with its 199€ price; my expense limit on eyepieces is precisely 200€. My reasoning is, the thing is modern, got out only a few years ago, so the optical design must be good, 82° optics technology is about 40 years old and became affordable long ago, the flaws of previous generations should be debunked by now.

 

https://www.astrosho...ab_bar_2_select

 

attachicon.gifoberon 32.png

 

The weight is an impressive 947 grams, 100 more than my heaviest eyepiece but the 115's focuser is very strong and accurate, so no big worries about that. Multicoatings and complete blackening are standard in that class, so no worries either there. The only question, how good is it?

 

Resolution at the center is always important but it's not the top priority in a gigantic true field, ultralow power eyepiece. The number one criteria will be edge performance because the objective's field and the eyepiece's field are both maximal and we know the edge is always where the results disappoint or not in widefield observing.

 

The question was asked in other forums but the answers consisted of beating around the bush, no a single straight one. So, does a Cloudy Nights member know and is willing to share, or shall I be the guinea pig?

I don't think it is possible for a 2" 32mm eyepiece to be 82 degrees. It's just a marketing ploy. It's more than likely 70 degrees like the 32mm Celestron Ultima LX, (and some other brands), and they labeled it as 82°.

 

https://www.bhphotov...Wide_Angle.html



#4 dark_night

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Posted 09 May 2021 - 08:55 AM

Have not used these. I was tempted myself but for some reason never pulled the trigger. What I found in my research is that people believe these to be optically same as Celestron Luminos.

#5 eyeoftexas

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Posted 09 May 2021 - 09:11 AM

This is an exact duplicate of the Astromania 32mm: https://astromaniaop...obstructed-view

 

 

I don't think it is possible for a 2" 32mm eyepiece to be 82 degrees. It's just a marketing ploy. It's more than likely 70 degrees like the 32mm Celestron Ultima LX, (and some other brands), and they labeled it as 82°.

A quick scan through the 2021 Buyer's Guide spreadsheet posted by Don Pensack (eyepiecesetc.com) does show that 82° at this and longer focal lengths are rare.  But, TV has 31mm 82°, ES has 30mm 82°, and Masuyama has 32mm 85°, so it is not impossible.  This is not to say that this one should be taken at face value.  You need to know the field stop of the eyepiece to tell.


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#6 Ben the Ignorant

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Posted 09 May 2021 - 10:11 AM

It's more than likely 70 degrees like the 32mm Celestron Ultima LX, (and some other brands), and they labeled it as 82°.

But the difference would be obvious, and they could be sued.



#7 Ben the Ignorant

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Posted 09 May 2021 - 10:12 AM

What I found in my research is that people believe these to be optically same as Celestron Luminos.

But what is that belief based on?



#8 Ben the Ignorant

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Posted 09 May 2021 - 10:17 AM

This is an exact duplicate of the Astromania 32mm

Yes, eyeoftexas, I had seen the Astromania page but no review, only blind ratings. There is one on Amazon but it's weird, the reviewer talks about Plössls and other focal lengths, and one test from an Amazon reviewer is not very credible, anyway.



#9 SeattleScott

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Posted 09 May 2021 - 11:11 AM

https://www.cloudyni...-82°-eyepieces/

It doesn’t look like anyone has been courageous enough to try them.

Scott

#10 f18dad

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Posted 09 May 2021 - 12:21 PM

https://www.cloudyni...-82°-eyepieces/

It doesn’t look like anyone has been courageous enough to try them.

Scott

 Be the guinea pig...



#11 Ben the Ignorant

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Posted 09 May 2021 - 01:24 PM

There's not much risk, my scope has a non-demanding f/7 ratio and all combinations of total objective focal plane with extreme wide angle eyepiece will cause some softening near the field stop. The 34mm/68° does not soften much at all at the edge of its 2°50' field so I can trust an eyepiece inspired from Nagler's 82° recipe, and made in a shorter focal length will do its job honestly.

 

I am adding this to the list of accessories for the 115 apo, a 9x50 Amici finder, a 7mm/100° and a 13mm/100°, and an EQ-5 or AZ-5 mount. The three Myriad 100° and 110°-class 9mm, 5mm and 3.5mm I already own costed around 180€ each (yes, new) so the similar price of that ultra wide angle 32mm is not a clue to so-so quality.

 

I'm confident it will be be good.


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#12 eyeoftexas

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Posted 09 May 2021 - 03:28 PM

Be sure to give us a full report.  waytogo.gif



#13 MitchAlsup

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Posted 09 May 2021 - 04:37 PM

I don't think it is possible for a 2" 32mm eyepiece to be 82 degrees. It's just a marketing ploy. It's more than likely 70 degrees like the 32mm Celestron Ultima LX, (and some other brands), and they labeled it as 82°.

 

https://www.bhphotov...Wide_Angle.html

Well, we know that the 31NT5 has 82º, so it seems to me that "one more mm" of FL and a larger body than the 31NT5 might just allow the light path to be unvignetted. That is:: it is so close the 31NT5 and with a larger body, it just might be able to fit the light path through.


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#14 naramsin

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Posted 09 May 2021 - 05:08 PM

It makes sense that it's a Luminos with different livery. If so, you may hate it, you may like it (I like mine). The Luminoses are nice when you decloak/unshroud them (an easy procedure, and mostly reversible). Then you no longer have the experience of holding a grapefruit shaped EP with a tea saucer-sized bezel to your eye. These Oberons look like the decloaked Luminoses, with a nice rubber coating. A sensible design!

 

I use the 31mm Luminos in slow scopes (80mm F11.3 and SW ED100) and like it just fine. Plenty of nice round stars.

 

The APM UFF 30mm is most likely a better purchase....YMMV


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#15 Jon Isaacs

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Posted 09 May 2021 - 05:14 PM

Well, we know that the 31NT5 has 82º, so it seems to me that "one more mm" of FL and a larger body than the 31NT5 might just allow the light path to be unvignetted. That is:: it is so close the 31NT5 and with a larger body, it just might be able to fit the light path through.

 

A 32 mm with a 46 mm field stop is possible. It might not be a negative-positive eyepiece, it might not be well corrected but it's possible. The 42 mm Field stop of the 31mm Nagler is the largest field stop TeleVue felt could meet their standards. Others are not so particular.

 

I calculate the a 32 mm eyepiece with a 46 mm field could provide a 82.3 AFoV.

 

There's not much risk, my scope has a non-demanding f/7 ratio and all combinations of total objective focal plane with extreme wide angle eyepiece will cause some softening near the field stop. The 34mm/68° does not soften much at all at the edge of its 2°50' field so I can trust an eyepiece inspired from Nagler's 82° recipe, and made in a shorter focal length will do its job honestly.

 

 

F/7 is actually rather demanding..

 

What you would trusting is that this eyepiece somehow is based on the Nagler and that itwas done reasonably well.

 

That's a rare occurrence...

 

The 34 mm 68° ES/Meade was modeled after the 35 mm Panoptic.

 

Jon


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#16 Starman1

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Posted 09 May 2021 - 05:25 PM

Speaking of Guinea pigs:

https://www.apm-tele...e-eyepiece.html

Also comes in 15mm, 10mm, 5mm.


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#17 russell23

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Posted 09 May 2021 - 05:32 PM

Probably same as that Meade Megawide series? Wasn't that also the same FL?
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#18 Starman1

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Posted 09 May 2021 - 05:40 PM

That's my guess.  Not bad prices for 88°+/-.


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#19 Thomas_M44

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Posted 09 May 2021 - 06:30 PM

I don't think it is possible for a 2" 32mm eyepiece to be 82 degrees. It's just a marketing ploy. It's more than likely 70 degrees like the 32mm Celestron Ultima LX, (and some other brands), and they labeled it as 82°.

 

https://www.bhphotov...Wide_Angle.html

It’s actually quite possible.

 

Search ‘Masuyama 32mm” in CN eyepiece forums.

 

It’s 83 deg AFOV —measured (a 5-element, 3-group design)


Edited by Thomas_M44, 09 May 2021 - 06:30 PM.


#20 CeleNoptic

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Posted 09 May 2021 - 07:13 PM

But what is that belief based on?

 

On knowing Chinese business model (rebranding everything) and some eyepiece researching/buying experience grin.gif


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#21 Jon Isaacs

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Posted 09 May 2021 - 09:25 PM

Speaking of Guinea pigs:

https://www.apm-tele...e-eyepiece.html

Also comes in 15mm, 10mm, 5mm.

 

6 elements... 

 

Jon


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#22 Ben the Ignorant

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Posted 10 May 2021 - 03:45 PM

I am a pig after all. I just ordered it, and will be reviewing it, of course. I plan to test the Oberon on each of my four 2" focuser telescopes, the 115mm f/7 triplet, an 80mm f/6 triplet, an 80mm f/7 semi-apo and a 300mm f/5 dob. I see what the procedure will be. Check the roundness of stars halfway or two-thirds of the way from the center, and right against the field stop, of course.

 

Compare coatings with other large eyepieces of that class, you'll see pictures; I don't like written descriptions when a picture needs to be shown. If I can't photograph the roundness I'll draw it. The other comparable eyepieces are: Sky-Watcher Aero 30mm/68°, Meade/MaxVision 34mm/68°, MaxVision/Meade 24mm/82° and Explore 24mm/68°.

 

Same with inside blackening, will check it with a laser, vigneting is at the top of the list of features to be examined, for sure, and eye relief will be shown this way so practical comparisons can be made:

 

eye relief fujinon.jpg

 

eye relief apm.jpg

 

It should be at my home a couple of days from now, but if that's too optimistic, should be before the end of the week at worst.


Edited by Ben the Ignorant, 10 May 2021 - 05:24 PM.

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#23 SteveG

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Posted 10 May 2021 - 04:53 PM

A few thoughts after reading your posts:

 

Modern vs 40 years ago means very little. Coatings have certainly improved, but the rest is subjective. Going back 25 years ago is when the best optically corrected eyepieces started coming out.

 

Weight has nothing to do with the quality of view. Yes, large lenses that are required for something like this are heavy, but it doesn't always equate to better edge correction.

 

No one get's sued for their marketing speak - at least not here in the states.

 

F7 is demanding, but not as much as f5. The 34/68 exhibits a little astigmatism at the edges in my f5 scopes. Your 800 mm focal length should show very little to no field curvature.

 

Do not trust that an eyepiece "inspired" by a Nagler will be anything close to a Nagler, especially at that price point.

 

I think the closest thing that is within your budget is the APM UFF30. Beyond that, you should look at the ES 30/82 or N31T4,


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#24 havasman

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Posted 10 May 2021 - 05:17 PM

"...ideal on paper..."

What could possibly go wrong?

and a +1 for the APM UFF30 at that general price point


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#25 Ben the Ignorant

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Posted 10 May 2021 - 05:39 PM

Weight has nothing to do with the quality of view.

No one claimed that.

 

 

No one get's sued for their marketing speak - at least not here in the states.

Claiming 82° when it's 70° would not be marketing speak, it would be false advertising.

 

 

I think the closest thing that is within your budget is the APM UFF30. Beyond that, you should look at the ES 30/82 or N31T4,

The only APM 30mm/80° I found in their page is a five-lens eyepiece, and that can't possibly be enough for a decently corrected 80°, is there another APM with those specs?

 

Lastly, my 200€ limit on eyepiece price is a hard limit, no exceptions, the Explore or Tele Vue cost too much, and I don't buy used.




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