79 replies to this topic

[Joe Cepleur]

Thank you; yet as the one who started the thread, I find the comparisons to higher-priced eyepieces interesting, and would rather not cut them off. They bring perspective. I'm getting the sense that, for big money, one can buy something approaching perfection. For under $100, one can buy good Plössls or good older designs used, provided that they suit you. At that price, one can also find eyepieces with what might be agreed are serious flaws, yet that may suit some observers who happen not to care about the imperfections. Of major interest to me is that, at the in-between prices of $100 to $300, there are plenty of good eyepieces, if one learns what to buy, offering most of what the expensive eyepieces offer, but without the perfection.

[Dave Mitsky]

The 70-degree AFOV 38mm Agena SWA should work well at f/10 and is relatively inexpensive.  The Astronomical Society of Harrisburg owns one that I use often in our SCTs and classical Cassegrain.  It's even not all that bad, as far as astigmatism goes, in the club's f/6 Newtonians. 

 

There are also 26 and 32mm versions.

 

https://agenaastro.c...a-eyepiece.html
 

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[Dave Mitsky]

By the way, I wouldn't wait too long to order as availability due to the tariff situation may be limited.

[Procyon]

I can make a whole set of these eyepieces below and be happy, new and/or used. Some are as low as 50$. Many have variations. Definitely get Don's eyepiece guide in the stickies to get a better idea.

Some examples:

30mm APM UFF (Many other variants, including the nicer looking Celestron ones)
28mm AT UWA (Other variants, but the Astro-Tech just looks better).
20mm AT XWA, APM, Sky-Rover, Etc, 13mm, 9mm, 7mm, etc
9mm Celestron X-Cel LX
7mm Celestron X-Cel LX
Most Meade HD-60 types, the 9, 6.4 and 4.5mm especially, even the others for SCT's, etc
SvBony Zoom 7-21
A lot of Vixens
Many Plossls
Many SWA's in the 16-42mm range
Parks Gold Series, Celestron Ultima, Omcon Plössl, Antares Elite, Orion Ultrascopic, Tuthill Plössl, Baader Eudiascopic, Kasai Astroplan types (These are all the same)

I think the best deals are the first three used in the classifieds or new, and especially all the XWA's. There's a lot more, do research them.

Edited by Procyon, 08 May 2025 - 08:44 AM.

[CollinofAlabama]

Joe Cepleur,

 

Sounds like you're in Europe?  Your request has some interesting parameters.  Because the F/4 scope will likely create exit pupils that you won't be able to use above about 23mm, I would recommend the one that Don Pensack recommends above, the 22mm 70° SWA of the various labels you can find that are convenient to you.  This one has the long eye relief you seem to require.

 

The F/10 refractor, of course, could even use a 56mm Plossl, and would work well enough, although in the 1.25" barrel if you've ever used a 24mm/25mm wide field (over 60° AFOV), and compared that view to the 32mm plossl, well, it's usually a nicer rendition on most targets.  This experience is even more dramatic with 2" eyepieces, which do wide field so much better than any 1.25" barrel eyepiece can.  Therefore, getting a 65°+ AFOV 40-ish mm eyepiece for the 6" refractor will be a better view, provided the eyepiece is well-corrected.  But a 56mm Plossl type eyepiece will still show the same huge field, just in a more tiny, less detailed, less contrasted fashion.  The higher magnification of the widefield darkens the background sky more than the longest focal length plossl type eyepiece can.  Therefore the 65°+ AFOV eyepieces produce a more contrasted image, with darker background space, highlighting the target more.  The 30mm UFF Don recommends above is a very nice choice for the refractor, again, with lots of eye relief, but Don might have some better choices for 40mm-ish sized widefields, too.  The only ones I know of that are well corrected are expensive, but if anyone would know, Don Pensack would.

 

Good luck

Edited by CollinofAlabama, 07 May 2025 - 05:52 PM.

[SeattleScott]

Thank you; yet as the one who started the thread, I find the comparisons to higher-priced eyepieces interesting, and would rather not cut them off. They bring perspective. I'm getting the sense that, for big money, one can buy something approaching perfection. For under $100, one can buy good Plössls or good older designs used, provided that they suit you. At that price, one can also find eyepieces with what might be agreed are serious flaws, yet that may suit some observers who happen not to care about the imperfections. Of major interest to me is that, at the in-between prices of $100 to $300, there are plenty of good eyepieces, if one learns what to buy, offering most of what the expensive eyepieces offer, but without the perfection.

That summarizes the situation well. Just understand that F5 is sort of the normal floor for visual. F4 is more common for astrographs. So the midrange eyepieces designed to be “good” at F5+ will be a bit less good at F4. Although a coma corrector could put one at F4.4 or F4.75.

Edited by SeattleScott, 07 May 2025 - 04:29 PM.

[Joe Cepleur]

There's always Plan B for the mini-Dob. Everyone's efforts are still well spent and much appreciated for all that I am learning.

Starting now, for the future, borrow every possible eyepiece I can and really study how they work. Tariffs be darned; wait until I really understand what I need to fill the ultra-wide view fantasies. In the mean time, throw on my existing 1.25" 2x Barlow, and continue using the mini-Dob as though it were a classic 6" f/8. Still has a fabulous mirror; still is dead easy to haul around!

Then, consider getting that 2-inch 40-somethingish mm wide field for the 6" f/10, and maybe an in-between size, too. Stick with my 1.25-inch collection for anything shorter than about 20mm, where 2-inch barrels would not matter.

I have only ever had long-focus scopes before, and so was always happy with simple 1.25" eyepieces: Plössls, orthoscopics, the classics. I never worried about exit pupils or anything else; I just swapped eyepieces until I got the best view. My sense from this thread is that moving to faster telescopes with 2-inch, wide-field eyepieces complicates everything, with the bottom line being that getting good, sweeping, wide views in the f/4 would be expensive. The friends whose eyepieces did the trick before must have had exactly the right kit, and paid plenty for it.

[Joe Cepleur]

What, please, do these abbreviations mean:

APM

AT

...in the context of these eyepieces?

30mm APM UFF

28mm AT UWA

Edited by Joe Cepleur, 07 May 2025 - 09:46 PM.

[Starman1]

What, please, do these abbreviations mean:

APM

AT

...in the context of these eyepieces?

30mm APM UFF

28mm AT UWA

APM is a German Telescope and eyepieces retailer that imports products under their own label.

AT is Astrotech, the private label for Astronomics, the host/sponsor of cloudynights.com

UFF is Ultra Flat Field, a line of eyepieces from Kunming United Optics in China.

UWA is Ultra Wide Angle, a moniker attached to eyepieces of 80-86° fields.

[SeattleScott]

Just to clarify, we talk about the APM 30UFF because it was the first to introduce the series. But the eyepiece isn’t only available in Germany. These days it is available in maybe 100 countries under say 1,000 different brand names. I exaggerate, but bottom line, if you see an eyepiece advertised as 30mm with 70 AFOV and it costs around $200, it is what we call an APM 30UFF.

[Starman1]

Just to clarify, we talk about the APM 30UFF because it was the first to introduce the series. But the eyepiece isn’t only available in Germany. These days it is available in maybe 100 countries under say 1,000 different brand names. I exaggerate, but bottom line, if you see an eyepiece advertised as 30mm with 70 AFOV and it costs around $200, it is what we call an APM 30UFF.

The 30mm was the last UFF eyepiece introduced and it came out a few years after the others.  It was the first 2" UFF, however.

As you mention, it is available under several labels:

Altair Astro (UK) UltraFlat
APM Ultra Flat Field
Celestron Ultima Edge
Sky Rover Ultra Flat Field
Stella Lyra (FLO) Ultra Flat
Stellarvue UFF
TecnoSky UltraFlatField

And, discontinued, but maybe in some dealer stocks:

Meade S5000 UHD

The other sizes are sold by even more vendors under even more labels.

Edited by Starman1, 08 May 2025 - 12:34 PM.

[Procyon]

I went back and edited my post to avoid any confusion. 

 

If I were just getting started in visual Astronomy, the first eyepiece I'd probably try would be a 20mm XWA, but that's a 2", otherwise for 1.25" I'd probably look for a 13mm XWA 100° Eyepiece 1.25"/ 2" or 9mm, 7mm... These eyepieces are used and liked by almost everyone here. Love my 20mm twist top version.

 

But they are heavy at 500 grams. Than I'd probably look for a 28 or 30mm as listed....

 

For smaller scopes and/or an even smaller budjet I'd look for all those Ultima/Parks Gold types and make a good set of those, maybe mixed in with used or new TV Plossls. 

 

Eyepieces don't have to be expensive to enjoy visual astronomy. Us eyepiece addicts make it look that way lol.

Edited by Procyon, 08 May 2025 - 08:14 PM.

[SeattleScott]

It gets expensive when you want a wide field with good correction to the edge at F4. If you don’t have a fast scope, or aren’t picky about edge correction, or don’t need wide AFOV, it doesn’t have to be expensive.

And if you want long ER, be prepared to pay a bit more.

So there’s something for everyone. If finances aren’t a concern, buy Nagler type 7’s and get great views with wide AFOV and long ER at any visual F ratio. If money is a constraint , then you might have to prioritize and compromise.

[csrlice12]

It's all a tradeoff....fast scope means well corrected $$$ eyepieces; slow scope can use cheaper eyepieces, but likely needs a sturdier mount/tripod....end result is it's gonna cost you one way or another.

[Jon Isaacs]

Just to clarify, we talk about the APM 30UFF because it was the first to introduce the series. But the eyepiece isn’t only available in Germany. These days it is available in maybe 100 countries under say 1,000 different brand names. I exaggerate, but bottom line, if you see an eyepiece advertised as 30mm with 70 AFOV and it costs around $200, it is what we call an APM 30UFF.

 

Others do sell the UFFs but Markus Ludes of APM commissioned Mark Ackermann to design the UFF series and had KUO to build them. 

 

I think calling it the APM UFF series recognizes their contribution.

 

There are a few other 30 mm 70° eyepieces. Explore Scientific made an entry level version that is not sharp at all across the field.

 

Jon

[SeattleScott]

Others do sell the UFFs but Markus Ludes of APM commissioned Mark Ackermann to design the UFF series and had KUO to build them.

I think calling it the APM UFF series recognizes their contribution.

There are a few other 30 mm 70° eyepieces. Explore Scientific made an entry level version that is not sharp at all across the field.

Jon

Agreed, no argument referring to it as APM.

The entry level ones cost a lot less than $200, so it makes it easy to distinguish.

[Joe Cepleur]

First, this just in from our friends at Sky Rover:

 

"To avoid the impact of high tariffs imposed by the U.S. on Chinese imports, we will temporarily stop accepting orders from the United States. The resumption time will be announced later. Thank you for your understanding and support."

 

This was my concern, that what I might afford would simply become unavailable at any price. Sky Rover is, of course, in China, where a hunk of the optical industry is now based. 

 

<><><><><>

 

My sense from everything I have learned in this thread is that there is, to me, a new element in choosing eyepieces (and, yes; I have been living under a rock for a while, content with a pile of classic telescopes and what has always been, for me, perfectly serviceable classic 1.25" eyepieces).

 

In the bad old days when every eyepiece had an apparent field of view of 45 to 50 degrees, some were better / sharper / more contrasty / had better eye relief / whatever than others, but generally the process of choosing which to use consisted of trying a bunch from my case, and using whatever worked best. Longer focal lengths brought wider fields, with the widest of all stuffed into narrower apparent fields. Now, there are two new (to me) elements: Clever optics that allow wider fields, and with that, the opportunity to select the desired exit pupil for a given field. Where a longer eyepiece used to show a wider true field inside the end of a straw, now a shorter eyepiece can show that same wider field at a higher magnification and smaller exit pupil. Neat trick! I have known about this for a while, but have never had to give it much thought when I was just peering occasionally through friends' eyepieces. 

[Starman1]

Hmm.  Sky Rover is the house brand of Kunming United Optics (KUO).

I hope that doesn't mean all KUO products will stop shipping to the US.

That would be a disaster.  

Edited by Starman1, 08 May 2025 - 02:16 PM.

[Joe Cepleur]

Disaster indeed!

 

Chinese manufacturers are not going to attempt to sell $300 eyepieces for $600 or $800. If items will not sell at the necessary prices to cover the 145% tariffs, there is no point in shipping them here. (I am in the United States, not Europe.) 

 

The 10% tariffs on Japanese and Taiwanese optics will cause their prices to rise somewhat, but not nearly so high as will the shortages in the market due to the lack of Chinese optics. Hard to say to what extent the American market will bear those increases, or whether these manufacturers, too, will reduce or end shipments. 

 

My bind is that I am starting a new business. Having already spent substantially on startup costs, I had pledged to be disciplined and hang on to my cash until the business was running. Then, having received two exceptional telescopes and appreciating how much better I have seen them be with 2-inch rather than 1.25-inch eyepieces, I decided to consider altering my pledge due to the altered situation of the tariffs.

 

It is clear that the 6" f/4 Dob would be too costly at f/4 to buy for now, but I could consider buying a 2-inch Barlow and a few eyepieces to suit it. At f/8, those eyepieces ought not to be so costly. If that sounds crazy, it's a legacy telescope because of who made it, and it is truly easy to transport. Besides, those eyepieces would overlap with what the other telescope needs. Having seen the 6" f/10 refractor with a friend's 2-inch Explore Scientific eyepieces, it seems a shame not to allow it to be all it could be. 

 

Disasters and decisions! 

[SeattleScott]

2” is only needed for low power. A 2” barlow is only needed for 2” eyepieces. So a 2” barlow is used to barlow low power eyepieces to medium low power. If you are happy with your medium power eyepieces, you don’t need a 2” barlow.

Just to be crystal clear, there is nothing fundamentally better about 2” eyepieces, other than being able to go wider at low power. And at F10 they need not be expensive. A $100 38mm SWA would be fine for the refractor. The reflector is going to be expensive. Because you can already get 65-68 AFOV at 24mm in 1.25” format. So to improve on that, you need 80-100 AFOV, and it needs to be corrected for F4, and not unbalance a mini Dob when used with the necessary coma corrector (good luck with that).

Now maybe the solution is the 30UFF. The exit pupil will be large, but probably not show secondary shadow? It is light, corrected for F4, and might be passable without a coma corrector.

What specific ES eyepieces are you referring to? This could help with determining what eyepieces you might like. There are also some ES eyepieces that are 2” but not really 2” eyepieces. For example, a 9mm 100 AFOV is 2” format if you get the ES model, but it is 1.25” for any other brand. So if you liked the ES 9mm 100, that doesn’t mean you like 2” eyepieces. That means you like hyperwide eyepieces. So it is important to see what eyepieces you like, and determine what it is that you actually like about them. You just need to understand the difference between an eyepiece that has a 2” barrel for convenience, and an eyepiece that uses a 2” barrel. Because if you really like your friend’s 10 Ethos or 17.5 Morpheus, and see that they are big eyepieces that go directly into a 2” focuser, you might come here asking for recommendations about 2” eyepieces. But you will just get recommendations for stuff like 31 Naglers, not 10 Ethos or Morpheus. Because those aren’t 2” eyepieces. They are just 1.25” eyepieces that have a 2” barrel for convenience of not needing to put in an adapter.

Edited by SeattleScott, 08 May 2025 - 03:33 PM.

[Joe Cepleur]

There is a really neat telescope simulator at:

 

https://telescopius....scope-simulator

 

It allows seeing the effects of the various eyepieces, so I tried the 38mm SWA from Agena Astro:

 

https://agenaastro.c...a-eyepiece.html

 

It has just slightly less field than a GSO 50mm SuperView, but at higher magnification and (?) a smaller exit pupil. That, in turn, is better than a 56mm Plossl with a 47-degree field. So, yes; the 38mm SWA looks good, and costs $105, not hundreds.

 

The Barlow? I was only thinking that sometimes two eyepieces and a Barlow yield, effectively, four eyepieces for not much more than the price of two. 

 

Interesting that the 30UFF may not need a coma corrector! 

[SeattleScott]

The 30UFF has supremely good edge correction, probably better than a 31 Nagler (granted it is narrower AFOV). It won’t cure coma, but at least with the 30UFF, the only thing you see at the edge is coma. Unlike most other eyepieces where you will see some astigmatism or field curvature at the edge too. So while the stars won’t be sharp to the edge at F4 with no coma corrector, you might feel it is good enough to not warrant messing with a coma corrector.

[Jon Isaacs]

Owning both the 30 mm UFF and the 31 mm Nagler, Id have to go with the 31 mm Nagler in terms edge sharpness.

 

However... It costs more than 3 times as much and weighs nearly twice as much. 

 

I think the 30 mm UFF is a winner here. The topic is expectations of low cost eyepieces. Before the 30 UFF arrived, no one compared $200 eyepieces to the 31 mm Nagler... I actually use my 30vmm UFF more often than I use the 30 mm UFF..

 

Its that good.

 

Jon

[Polyphemos]

Hmm.  Sky Rover is the house brand of Kunming United Optics (KUO).

I hope that doesn't mean all KUO products will stop shipping to the US.

That would be a disaster.  

I don’t get the joke?

 

If KUO stops shipping to the USA won’t that mean AstroTech telescopes and many eyepieces presently sold by Astronomics will be unavailable once existing stock runs out?

[Joe Cepleur]

"30UFF... the exit pupil will be large, but probably not show secondary shadow?"

That would be important to know, where I sometimes see secondary shadows. Other than that, it sounds suitable for both telescopes, and a real value buy.