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Q about Expanse Eyepiece & Clones

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#1 Joe1950

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Posted 15 January 2017 - 10:55 AM

Hello eyepiece ladies and gentlemen.

 

At an ever increasing age, I think I'd like to retire my small collection of Plossl eyepieces. They are very good and reasonable in price, but the eye relief has been becoming a more important issue.

 

So, my plans are to eventually, as funds permit build a small set of 82o Explore Scientific eyepieces. ES is my favorite company, for several reasons, and I find their eyepieces comfortable and capable, and (especially when they throw a sale on) affordable. 

 

That's not to take away anything from any other brand at all, they are just in my zone.

 

In the meantime, and to fill in any FL gaps, I've picked up two, used in good condition Orion Expanse types. One a 6mm Expanse and a 15mm clone, on the way to in the mail.

 

 

I read somewhere they are based on the Erfle design. Does anyone know it that's true? If not, what design are they close to, if known?

 

Also, anyone with these, I'd welcome your assessment.

 

Thanks very much. Oh and I'll use these with a 6" f/6 DOB, a 102mm f/9.8 Ach, and a 80mm f/7.5 C80ED.

 

joe



#2 CP Kuiper

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Posted 15 January 2017 - 11:18 AM

It's my understanding the Expanse and similar are all made by one company, then just branded for each different seller.

For example you can get the same eyepieces from Agena Astro for less than what Orion charges but Agena Astro doesn't use the Expanse name.

 

The Plössl design uses 4 elements (2 doublets). The Expanse eye pieces have 4 elements.

Erfles usually have a 5 element design.


Edited by CP Kuiper, 15 January 2017 - 11:21 AM.


#3 Augustus

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Posted 15 January 2017 - 12:13 PM

The 15mm and 20mm are normal Plossl derivatives, the 6mm and 9mm are Plossls with a Barlow built in to shorten the focal length w/o compromising eye relief.

 

I was given a 9mm Expanse and I enjoy using it with smaller scopes.


Edited by Augustus, 15 January 2017 - 12:13 PM.


#4 BillP

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Posted 15 January 2017 - 02:01 PM

The Expanse / Owl / EWA line is a 1-2-1-1 design for the 9mm and 6mm.

 

Expanse - Owl Deconstructed.jpg



#5 Joe1950

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Posted 15 January 2017 - 02:15 PM

Thanks Keith and Augustus!

 

I think there is also a 6 element variation of the Erfle where the center element is a doublet rather than a simple double convex.

 

Way back when, there were big giant surplus 32mm or so Erfles available at Edmund Scientific. They weren't well corrected at the edge of the field (about 65o, which was wide back then). So some of the guys referred to them as Awful eyepieces, rather than Effle. But they were wide compared to the Kellners and Orthos of the time which were about 40 and 45o.

 

In the early 1060s, my dad worked at the Frankford Arsenal in Philadelphia, He knew an optical engineer named Wright H. Scidmore, who developed a six element eyepiece for the Army with a 90o FOV. That was incredible for that time and the design is named after him. For some reason it never found its way into the consumer market and ultra wide field eyepieces wouldn't become available or popular until Al Neglar came on the scene about 1980. 

 

Anyway, whatever these eyepieces are, they have a nice fov and eye relief and seem to be sharp, so I'll use them along with any ES 82o I can collect. Both the 66o and the 82o are plenty wide for me. The added eye relief helps a great deal.

 

And Bill! Look at that! Nifty indeed!

 

I didn't know you are the same Bill as William Paolini, noted author and reviewer! I just got Choosing and Using Astronomical Eyepieces, of the Patrick Moore Series from Amazon Kindle! Wonderful Book!

 

Thanks guys!


Edited by Joe1950, 15 January 2017 - 02:16 PM.


#6 Joe1950

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Posted 15 January 2017 - 02:32 PM

So the 6mm and 9mm Expanse and clones would be as the 9mm pictured, 1-2-1-1. For 5 elements.

 

The 15 and 20mm would do away with the field side lenses, and be 1-2. For 3 elements? Or do you think they have 4 elements toward the eye lens side?

 

It doesn't matter to me what they are, as long as I don't have to put them on like contact lenses like the Plossls :grin: . Really Plossls are fine eyepieces but I'm too old and lazy anymore to strain to see something. 



#7 Jon Isaacs

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Posted 15 January 2017 - 02:48 PM

Joe:

 

The 20 mm and the 15 mm are quite different eyepieces than the 9 mm and 6 mm.  According to Orion, the 15 mm and 20 mm are 4 element eyepieces, I suspect they're some sort of Erfle variant.

 

The 9 mm and 6 mm are much better corrected in a fast scope. These eyepiece share a lot with the TMB planetary series. They are modular, there's the front 1.25 inch barrel with the Barlow like negative section, a body with not optics and a positive magnifying section that threads into the body.  These three sections are not identical but they are interchangeable, not only between the the 9 mm and 6 mm Expanses but also between the Expanses and the TMBs..

 

jon



#8 Joe1950

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Posted 15 January 2017 - 03:14 PM

That makes sense, Jon. Thanks. That's probably where I heard the connection with the Erfle design, but a variant.

 

I did pick up a 15mm, used, and it should get here Tues.

 

So many designs and variations off the designs, it's hard to keep up with now-a-days.  :shrug:



#9 Jon Isaacs

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Posted 15 January 2017 - 03:43 PM

That makes sense, Jon. Thanks. That's probably where I heard the connection with the Erfle design, but a variant.

 

I did pick up a 15mm, used, and it should get here Tues.

 

So many designs and variations off the designs, it's hard to keep up with now-a-days.  :shrug:

Joe:

 

Ain't that the truth.. But on the positive side, I think there are lot of pretty good eyepieces out there that are most affordable.  When I was moving towards wider fields of view and better corrected designs for my 12.5 inch F/4.06, I had a collection of ortho's, Plossls and Erfle's, there really wasn't much in the under $100 range like there is today. 

 

The Meade Series 4000 UWAs, the Naglers, the Panoptics, that was what there was in the way of wide fields of view that worked well in fast scopes.  

 

The Expanse series represented a breakthrough, I think I was able to buy the 15mm, the 9mm and the 6mm from Adorama on a buy two get one free deal for about $120.  Later I had the 20mm and several of the 6mm and 9mm.  To my eye, the 9mm was the best of the lot and as I was slowly buying older Naglers, the 9mm Expanse hung in there, it was the last non-TeleVue eyepiece in my main case and sat between the 7mm type 1 Nagler and the 12mm Type 2.  

 

Eventually a 9mm Type 6 showed up on the local Craigslist and replaced the Expanse but I use 9mm eyepieces a lot and it did a good job, some memorable views..

 

Some people like to see pristine, never been touched eyepieces.  Me, I like to see eyepieces that have been used and loved.  My 9mm Expanse, I literally wore the markings off the body and look at the marks on the barrel.  You can tell that eyepiece had been in the focuser many thousands of times..  It takes a pretty good eyepiece to get that kind of love and attention.. 

 

Jon

4474639-Synta Widefield 9mm.jpg


#10 Joe1950

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Posted 15 January 2017 - 05:03 PM

Great account, Jon. That certainly is the highest of compliments for anything - use, and a lot of it.



#11 MartinPond

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Posted 15 January 2017 - 06:16 PM

The layout is pretty clear.

 

The 20mm Expanse  is a 1,2 Konig  with an extra element added for more field correction.

 

The other Expanse models are also 1,2 Konigs but with 2 more elements far forward,

as a Barlow group.   If you use them as a Barlow with another eyepiece type,

you see the power effect, but the edges degrade a little.   So the forward 1,1 is

both Barlow and field correction for the 1,2 Konig which is nearly a duplicate of the

20mm Expanse eye set.

 

So.....corrected 1,2 Konig  ,  and Barlowed, corrected 1,2 Konigs.

 

 

A common commercial 1,2,1 Konig has a much stronger front lens, low eye relief,

   and is hard to correct.

An Erfle  is 2,1,2, and doesn't look anything like any of the Expanse line.


Edited by MartinPond, 15 January 2017 - 06:19 PM.


#12 Joe1950

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Posted 15 January 2017 - 06:47 PM

That sounds good to me, Martin. Thanks for the info!



#13 RickV

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Posted 15 January 2017 - 06:55 PM

I have all four eyepieces and if I recall correctly the 6mm and 9mm were more highly rated in the reviews (yes, there are reviews) than the 15mm and 20mm.



#14 Joe1950

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Posted 15 January 2017 - 06:59 PM

What do you think of the 15mm and 20mm Rick?



#15 MartinPond

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Posted 15 January 2017 - 09:05 PM

The 6mm and 9mm have rather potent smallish Barlows,

so they are practically immune to F5 (or maybe even less) barrels.

The small front, spacing  (and blackened interior) cause a rather deep contrast.

They even mop up some baffling issues on scopes. Not bad for the price even before

the clones were made.  But they leave well enough alone at 66 degrees.

 

The 15 and 20 can't take advantage of all that, but they still have that field grace at F6 and up.


Edited by MartinPond, 15 January 2017 - 09:07 PM.


#16 Joe1950

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Posted 15 January 2017 - 09:46 PM

My 6" f/6 newt is the fastest scope I have. Sounds as though they are a good value and good quality line. Certainly the eye relief appeals to me and 66o is plenty. In fact, 82o is at the upper limit of my taste buds. The ES 82o line is the widest I would want - just my preference.

 

Anything from about 60 on up to the 82s in right in my comfort zone.

 

Speaking of ES eyepieces, hopefully not to go off topic too far, I noticed a couple merchants promoting a 62o under the ES name, not Bressler, and they are priced at $99. I wonder if that is a new line for them? Most of the FLs are not in stock yet. And they start with 5mm, I believe, and are Argon purged.

 

Anyway, I appreciate the good information on these Expanse types, Martin, and I think a couple two or three of the clones for the in between focal lengths will fill the bill.

 

I'm not one to have too many eyepieces. Just enough the get the right view. 


Edited by Joe1950, 15 January 2017 - 09:49 PM.


#17 dufay

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Posted 16 January 2017 - 04:16 AM

 

 

Speaking of ES eyepieces, hopefully not to go off topic too far, I noticed a couple merchants promoting a 62o under the ES name, not Bressler, and they are priced at $99. I wonder if that is a new line for them? Most of the FLs are not in stock yet. And they start with 5mm, I believe, and are Argon purged.

 

 

 

Yes it is a new eyepiece line. Here is the thread: http://www.cloudynig...62-degree-line/



#18 Joe1950

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Posted 16 January 2017 - 06:55 AM

Thanks, Jan. That's good to see. If they have the build of the other series, they should be popular.



#19 Terra Nova

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Posted 17 January 2017 - 08:26 PM

I have a set that I purchased soon after Orion first brought them out, close to 15 years ago now. I used to use them with a Stellarvue 80/9D that I had att he time. I currently use them with my Celestron C4.5 (4.5" F8 Newtonian) and my Celestron C80 F11.7 refractor. They work well with moderate to longish focal lengths. I did not like them with my shorter focal length scopes where I prefer Vixen LVs. Both the Vixen LVs and the Expanses have 20mm eye relief, however the expanses produce noticeably wider fields (AFOV ~66deg compared to ~52deg). They barlow well with a three element 2X Celestron Ultima apochromatic barlow. I keep them in a small eyepiece travel case along with the apo barlow, a 35mm Orion Ultima, and a variable polarizing filter. Since I have kept them all these years I see that as some testament to their worth, at least to me. You may have seen this. If not, you might find it useful:

 

http://www.cloudynig...mm-and-6mm-r255



#20 Joe1950

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Posted 17 January 2017 - 08:52 PM

Thanks Terra! Very interesting info. I've heard, and the review supports that the 9 and 6mm are very good planetary eyepieces. And that's what I would need the most. The fov and eye relief are also good for what I'm comfortable with.

 

I have the 6mm and 15, both picked up used at good prices, and I'll get the 9 and maybe the 20 down the road. Getting to the point in life where comfort is job one!  :grin:

 

Thanks again! 



#21 gene 4181

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Posted 18 January 2017 - 06:52 PM

  I've got the 20mm and the 6mm ,  got them  from Stellarvue . Green trim ring.   Quite awhile ago


Edited by gene 4181, 18 January 2017 - 06:53 PM.


#22 Joe1950

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Posted 18 January 2017 - 06:56 PM

How do you like them, Gene?



#23 telesonic

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Posted 18 January 2017 - 09:01 PM

I've got the full set of the clones - the Starguider version from Agena. Only had them since last summer, and bought them just because I heard the reviews were pretty good. Now, I don't have any "premium" eyepieces to compare them to save for a few super plossls in similar focal lengths.

 

The 6mm and 9mm I like very much, and have used them many times in the short tube f5 80mm scope - they seem to perform pretty good in that scope from what I can tell. The 15mm and 20mm maybe not as good, as some said because of the fact it's a faster scope.

 

In the 4.5" newtonian at f8 they are all good, much more so than the similar plossls.

Haven't got the chance to try them in the SCT yet, but I'm expecting them to be great in that scope too.

 

The 6 and 9 are definite favorites out of the set. IIRC it was the 15 that had some particles of black paint (specks) on the inside, but they came off with a quick air dusting.

 

While I don't view with glasses - the girlfriend does, and the eye relief is fine for her. Not so much with plossls.  :smirk:

Hope this helps.

T



#24 Joe1950

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Posted 18 January 2017 - 09:18 PM

That helps very much T.  I'm mostly interested in the 6mm, which I have but have not been able to use due to the lousy weather and the 9mm which I'll also get the Starguider clone. They seem to be good planetary eyepieces from what most say and that's what I'd use them for.

 

In my area, deep sky is almost impossible with the sky pollution, so the longer FL eyepieces don't get too much use except on open clusters.

 

Thanks a lot, T.

 

I have a cousin who lived most of her life in Calif. but mover to Idaho a couple years ago and really likes it there. She says the humidity where she lives is usually very low. I'd like that too!



#25 telesonic

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Posted 18 January 2017 - 09:44 PM

No problem!

The 6mm and 9mm did get used last fall on Saturn, and the girlfriend was pleased with the views for sure. Pretty good on the moon as well, and they get much use there.

 

Grew up here, and the town is bigger than it was back then, so more light pollution. But, it's still pretty dark out compared to other places. (or at least I hear)

 

Humidity is low in the summer / fall. Not so much right now. 90% with snow, lotsa snow - like 18-20 inches on the ground. Snow stacked everywhere. Most since '88. Snowmageddon. - yay.

 

I think you will be happy with those ep's. I certainly wasn't expecting much when I purchased them due to price, and even if some more expensive ones come along to the collection, I doubt I'd part with the Expanse's. 

 

CS,




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