Don Pensack

Circle V is Vixen.

As for the prism, it'll depend on age.  Some old ones are uncoated or have only MgF2 coatings.

Brand new stuff from Japan has multi-coatings on the outer surfaces.

7 hours ago, Figgis said:

Hello All.

                I've seen what Baader advertise as the Fieldstop measurements on their range of Hyperion Eyepieces but wonder what the rule of thumb is for measuring them or indeed checking what they say is Gospel.  Any and all comments welcome.

There is a fairly easy way.

1) pick a star on or very near the celestial equator.

2) time exactly how long it takes to drift across the field, through the center, from edge to edge.  Do 3 timings and pick the longest one (that one is likely to have passed dead center)

3) convert minutes and seconds to decimal minutes (example, 4 minutes 12 seconds = 4.20 minutes).

4) divide by 3.99.  The figure derived = the field in degrees.  Now you know the exact field of view in your scope with that eyepiece.

Then, calculate the field stop using this formula:

Field stop = (True field x telescope FL in mm) / 57.296

FS = (TF x TFL) / 57.296

The degree of accuracy is not exact, but you can get within 0.1mm, usually.

A calculated way to checking the figure derived is the following formula:

FS = (AF / 57.296) x EPFL

AF = apparent field

EPFL = eyepiece focal length.

This formula is almost never right because manufacturers lie about the exact apparent fields of the eyepieces and because focal lengths are often slightly off (maybe +/- 0.1mm)

But it gives a rational check number to see if your measurement is in the ballpark.

specs show 3.9" tall, 2.0" wide, 11 oz. for the Orion Pro / Stella Lyra 1.25" Lanthanum Zoom.

I don't know about a DioptRx, but if the 20mm eye relief figure is true, one would be usable as long as it can attach.

Someone else would have to remove the eyecup to test.  I cannot advise.

I would just call FLO and ask.

The stock diagonal likely needs cleaning.  I clean mine every time I clean the eyepieces, mostly by blowing out any dust.

And once a year, remove and clean the mirror, just as a newtonian telescope user dos.

Several years ago, with the same Maksutov, I compared about a dozen star diagonals.

I could not really detect differences in transmission, because you cannot see a difference less than about 10%, but I could definitely detect differences in image sharpness and light scatter.

There is really no reason to think about 2" eyepieces for that scope--the design is optimized for field stops of 27mm and smaller.

In 1.25" star diagonals, it was pretty much the "luck of the draw", with the best mirror award going to the TeleVue Enhanced Coated star diagonal.

A few runners up were the stock multi-coated Celestron 1.25" prism diagonal (but I couldn't get past the plastic housing) and a Lumicon 1.25" Enhanced Coated diagonal (no longer in production).

The differences in image sharpness were quite subtle, and required a LOT of time going back and forth.

However, the difference in scattered light was more noticeable, which is why I kept the TeleVue, which had the least light scatter of any of them.

I also noted the TeleVue diagonal had the largest clear aperture of all of them except the Celestron prism, which only mattered on a 24mm Panoptic or 32mm Plössl, both with the maximum field possible in 1.25".

By the way, some actual specs for the scope:

With the 1.25" visual back, the focal length is ~1540mm with the average 1.25" diagonal.

The clear aperture is actually 121mm because rays from the edge of the aperture miss the primary mirror.

That makes the scope f/12.7.

If the threads on the back of the visual back are removed, the focal length shrinks to 1518mm and the scope is f/12.5.

That makes the maximum field with 1.25" eyepieces around (depends on the eyepiece) 1.02°, which is pretty good for that f/ratio.

In fact, it's a decent scope to use a 40mm Plössl in, because it yields 38-39x, a decent low power for the aperture (if you can tolerate the narrow apparent field of ~40°).

The 40mm, and to some degree, 32mm are not good in the daytime due to the large secondary shadow.  For terrestrial use, I preferred a 24mm 68° eyepiece.

Three things influence magnification sequencing:

1) aperture.  Larger apertures can use higher powers than smaller scopes, so the jumps between high power eyepieces can be larger without excessively dimming the image.  In essence, the larger the scope, the bigger the steps can be.

2) apparent field.  Larger apparent fields can have bigger jumps without making the true fields too small.  A 20mm to 10mm 100° jump is the same magnification jump as a 20mm to 10mm 50° jump, but many would find the 10mm 50° field is too much smaller than the 20mm.  This is a logical reason to increase apparent fields of the eyepieces as you go shorter in focal length.

3) choice of targets.  Lunar/planetary specialists might want the high power jumps close together to bump up against the seeing limit slowly and to keep magnifications from getting excessive.  A 40% jump at 50x is not that much.  A 40% jump at 300x is huge.

#1 points to smaller jumps on smaller scopes.  An 8" might move upward in 50x jumps, but a 20" might be able to handle 100x jumps (commensurate with seeing, of course).

#2 points to smaller jumps with smaller apparent fields.

#3 points to having multiple high power eyepieces if your viewing tends toward moon, planets, double stars, small planetary nebulae.  It points to multiple low power eyepieces if your viewing is large, faint, nebulae with filters.

So there is no perfect rule.

In my own case, I have a nearly ideal medium power eyepiece and I gradually increase the magnification spread each direction that I move away from it, so the magnification changes look a bit like a "U".

I use low powers and high powers about equally but I spend most of my time with medium powers so it made sense to optimize the view there.

Even jumps (even #, not even %) make a lot of sense.  It results in smaller % differences as magnifications go up (benefitting moon, planets, double stars), and noticeable magnification changes at low power (where even % results in close magnifications that provide no observing benefit.

But, the even jumps might be adjusted for aperture, like 50x jumps in an 8" scope, but 30x jumps in a 4" scope.  Experience will teach you what's best for your own viewing style and scope size.  A 40% jump probably works between 100x and 300x, but above and below that, it's a bit questionable.

After acquiring too many eyepieces, with magnifications too close together, it behooves all of us to seriously look at which eyepieces we actually use, and to space out the eyepieces a bit farther apart, magnification-wise.

If you have eyepieces at 100x, 120x, 140, 160x, etc, then changing eyepieces becomes as time consuming as observing the objects.

I always tell people: buy eyepieces far enough apart you can see a visible difference in the object when changing.  If, after quite a bit of time with such a set, you find yourself constantly wanting an eyepiece in between two of the ones

you have, it is certainly easy enough to acquire another eyepiece.

But reading Mark's comments merely makes me aware I have too many eyepieces and that I need to "cull the herd".  The question is, which one(s)?  It's a Sophie's choice.

The wider the field, the more distortion an eyepiece has at the edge of the field.

Rectilinear distortion, RD, which either stretches (pincushion) or compresses (barrel) radial lines is found in just about all eyepieces.

Usually pincushion is chosen to mitigate other aberrations (like chromatic aberration).

Pincushion distortion makes straight lines look like this as they cross the field  )  |  (

Barrel distortion makes straight lines look like this as they cross the field  (  |  )

Our eyes see up to 7% pincushion distortion as undistorted, so this is the form of RD chosen in 98% of all eyepieces.

Its primary noticeability is in panning across star fields.  Barrel distortion is especially noticeable this way because it makes the field look as if it is passing over a ball behind the field (aka rolling ball distortion).

The presence of rectilinear distortion reduces the effects of angular magnification distortion, AMD, which changes the magnification of the eyepiece from center to edge.

This type of distortion is worse, since objects tend to shrink or grow as they near the edge of the field.

If the magnification is lower at the edge of the field, the background sky might be brighter, which is also a negative.

As RD goes up, AMD goes down, and vice versa.  Some designers opt for some of both.  I see that in a lot of binoculars.  It isn't the best solution for astronomy, however.

Field curvature, where focus at the edge of the field is a different place than the focus at the center, is only a problem if your eye cannot accommodate the change in focus.

Older people, whose eyes accommodate less, have more problem with this than younger people.

Many people are unaware that refractors have inherent field curvature and may interface with eyepieces to yield more visible field curvature than reflectors.

Old eyes and refractors may not go well together, especially a refractor as small as 60mm.

Field curvature might be completely unnoticeable if the curvatures of eyepiece and scope match.  In essence, ) + ) = |

In can be atrocious if the curves are opposite, like ) + ( which puts the edges of the field very far out of focus when the centers match.

You will see this in reviews where someone comments on the field curvature in an eyepiece, when it is really the mismatch between eyepiece and scope.

) in the scope + | in the eyepiece (flat) = ) to the eye.

Eyepieces can be designed to have nearly zero noticeable distortion at the edge of the field.  The absence of distortion, or orthoscopy, will confine the eyepiece to very narrow apparent fields, however,

like the 42° fields in most Abbe orthoscopics (Abbe was an optical designer).  Wider fields of view cannot be orthoscopic.

Then there is astigmatism in eyepieces, which is a worse problem, but that is a discussion for another post.

5 hours ago, Alan White said:

I have churned eyepieces for many years looking for the ones that work as a small set,
sadly with changing scopes and tastes the collection has grown and shrunk at times, but never done.

I often regret selling items though, sometimes buy another and then realize why I sold the other one on.

The most likely of my collection to go is the Pentax XW 5mm, it is not often used and I have others at this length.
I might even do the same with the 7mm XW as well.

I went back to Delites for easier balance with the Refractors, and this may be the path I take, undercuts and all.

 

Fortunately, the undercut has a cylindrical cut, so it can be filled with metal tape (copper or aluminum), which essentially does away with the undercut.

I've done that with all my eyepieces with undercuts, and they slide into and out of the focuser/adapter/Paracorr without issue.

I even did that to the adapter provided in the Paracorr, and it slides in and out without catches.

It's a shame you have to do this, but it is a way to solve the problem of undercut barrels without harming re-sale down the road because the tape can be removed.

1 minute ago, Louis D said:

You're right about EOFB.  It's way too subtle to show up in my images.

The worst for EOFB I've found is the 12mm NT4.  It has a lightening that starts out bright at the edge and gradually gets dimmer toward the center, but never goes away completely.  I swapped between it and the 12mm ES-92, 14mm Morpheus and 10mm Delos, and none of them were showing any field brightening like that.  I'll have to check the 12.5mm APM for that next time I'm out since I didn't have it at the time I noticed EOFB in the Nagler.  I can't recall it being objectionable so far in it, but I also haven't been faint fuzzy hunting with it.

My images also don't reveal field curvature since the taking lens has quite a bit of depth of focus mimicking human focus accommodation.

Also look for EOFB in the 13mm AF70, where it is quite excessive.

5 minutes ago, Louis D said:

I was kind of put off by the 14mm Delos needing a negative profile 2" to 1.25" adapter to make it parfocal with the majority of my eyepieces that focus at their shoulder.  I'm not even sure it would fit down inside the necessary distance thanks to its rather thick lower barrel.  Tele Vue sells their In-Travel Adapter ($53!!!) for it, but I'm not sure it actually recesses the eyepiece a full 0.25" when you figure in the adapter's lip thickness.  Here you've already paid a premium for the eyepiece, and it's not even parfocal with most other eyepieces, nor does it come with an adapter to help it be more parfocal.

My 25mm Paradigm (BST Starguider) already won't come to focus in my Dob's low profile focuser with the GSO CC in place, so I know I'm close to my in-focus limits.  I've already shifted my primary mirror forward as much as I'm comfortable doing.  My focuser's 2" to 1.25" adapter is already a zero profile adapter, so that leaves a negative profile adapter as my only option.

The Delos fully inserts in the TeleVue In-Travel adapter.  The Paracorr adapter has a +10.5mm height, and the In-Travel adapter is -1.5mm, or 12mm lower.

That is merely to make the 14mm and 17.3mm Delos parfocal with all the other focal lengths in the Paracorr.  The 14mm and 17.3mm can be used in the Paracorr with the Paracorr adapter, but they focus much farther in than the other focal lengths.

That is why they do not provide a free adapter to make them parfocal with the other focal lengths of Delos.  They can be used without it by refocusing the scope or Paracorr top.

Judging by what I see in the field and comments from observers, most people simply don't care whether their eyepieces are parfocal and only run into an issue of in-travel if the scope runs out of the necessary amount of it.

By the way, the In-Travel adapter of TeleVue does not make the 14mm Delos parfocal with other eyepieces that have their focal planes at the 1.25" barrel shoulder--it makes the 14mm parfocal with the other Delos, all of which have their focal planes 0.25" below the shoulder.

Probably the reason I don't see any issues at the edge with the 14mm Morpheus is because I use it with a Paracorr, which eliminates coma and provides some field flattening.

That and the 1826mm focal length in the scope which results in a very flat field in the scope.  I do see some FC in my refractor, with a 714mm focal length and typical short radius of curvature of refractors.

My bête noire is edge of field brightening.  Louis' photos don't show that.  Several of the eyepieces he imaged above have that characteristic and I find them unusable as a result.

1.25":

https://www.firstlightoptics.com/barlows/astro-essentials-125-2x-barlow-with-t-thread.html

https://www.firstlightoptics.com/barlows/celestron-2x-universal-125-barlow-old.html

2":

https://www.firstlightoptics.com/barlows/stellalyra_2x_2_barlow.html

https://www.firstlightoptics.com/barlows/skywatcher-ed-deluxe-2x-two-inch-barlow-lens.html

7 hours ago, Davesellars said:

You're probably right... I have the 7mm and 5mm Pentax XW so a 2X Barlow would give 3.5mm and 2.5mm.  I'm not keen on extending the optical train, but this may well be the better solution.

Edit...  Or even a 3X barlow with the Delos 10mm giving 214xmm (useful) and with the 7mm Pentax 306x (useful for double stars and Mars / Saturn?)

If you get a decent 1.25" barlow of the type where the lens unscrews from the tube, then you have 4 magnifications from one barlow:

threaded to the eyepiece ~1.5x

in its tube under the eyepiece-2X

threaded to the front of the star diagonal--2.5x

in its tube in front of the star diagonal ~3x.

You would have to do star timings to determine the actual magnification factors in each position, but the idea is one barlow adds 4 additional magnifications.

If you have a 2" diagonal, then the 4 positions are: threaded to the 1.25" adapter, in its own tube under the adapter, threaded to the front of the diagonal, in its own tube in front of the diagonal.

The 13 Nagler is out--too little eye relief compared to the others.

Pentax--69.4° (measured)

Delos--72° (one report of 73° but anecdotal)

Morpheus--78° (measured)

I can only report what I see in my 12.5" dob at f/5.75 (with Paracorr coma corrector).  You might see something different without a coma corrector or in a shorter scope with more field curvature.

Pentax--edge of field very slightly astigmatic, but excellent contrast.  Easy to use with glasses.  Eyecup rolls up but very slowly due to fine thread.

Delos--edge of field sharpest of the 3, but needs about 1/2" of inward focusing compared to the other 2.  Excellent contrast. Easy to use with glasses.  Eyecup slides up and locks in place.

Morpheus--edge of field sharp, parfocal with the Pentax,  superb contrast, Easy to use with glasses.  An eyeguard extender is included, giving 4 different heights for the rubber eyeguard.

You can't lose with any of the 3, but the apparent and true field of the 14mm Morpheus is widest, and noticeably so, if that matters to you.

I wear glasses and went with the widest field, but none of the 3 is lesser compared to the others. 

If I didn't wear glasses, the 13mm Nagler would be a contender.  It's 79° (measured) and excellent in every way except eye relief (you might get eyelash oils on the lens).

Plus, it's very small compared to the others, a remarkable feat.

You picked 4 really high-end eyepieces.  Which do you prefer: Lamborghini, Ferrari, Maserati, or McLaren?😄

7 hours ago, Louis D said:

Weight wise, that puts it squarely between its two nearest LER competitors that I own, the 22mm AT AF70 (Omegon Redline SW, etc.) at 494g and the 22mm TV NT4 at 680g.  There's also the 20mm Pentax XW at 365g, but it suffers from field curvature, so I've never bothered with it.  The 22mm Vixen LVW comes up short in AFOV at 65 degrees.  I suppose I could include the 20mm APM XWA HDC which reportedly yields about 70 degrees AFOV with eyeglasses.  It weighs 680g, so basically the same as the NT4.  Since the Astro Tech version costs $250 right now, it's a very close competitor price wise as well ($12 more once VAT is subtracted).  The 17mm ES-92 has a field stop nearly as large as the 22mm AF70, so it could also be included in a LER comparison.

Any other 70 to 85 degree LER eyepieces in the 20mm to 22mm range?  I keep hoping ES will release a 23mm ES-92, but that seems highly unlikely now.  There's the 21mm Ethos, but paying that much for at most 70 degrees AFOV with eyeglasses seems like a total waste of money.

You can download a 2022 guide to all eyepieces here:

https://www.cloudynights.com/topic/813708-2022-eyepiece-buyers-guide/?p=11746324

Everyone keeps mentioning the Vixen LVW, but I don't think most people realize they were discontinued around 15 years ago.  There can't be that many used ones around by now.

But 70-85° with long eye relief in 20-22mm?

StellaLyra 80° 20mm

Orion LHD 80° 20mm

TeleVue Nagler T4 22mm

Pentax XW 20mm

Omegon Redline 22mm (also know as Telescope Service Expanse, Tecnosky SWA, Astromania SWA), and the (now gone) AT AF70 and Olivon 70 and Arcturus 70 and Celestron Ultima LX

There may be others, but I can't remember them off the top of my head.

In the US, the Vixen distributor was not that promotional, and he recently retired.

Explore Scientific in the US has become the current distributor of Vixen in the US (!).

Vixen was slowly making inroads in the US eyepiece market, but when the SSWs and HRs were discontinued it seriously reduced their market share, since those were the most popular Vixens.

Vixen never did well with the NPL and SLV here because they cost significantly more than the ubiquitous Chinese eyepieces for $10-$50 and have narrow fields.

With very good 60° eyepieces in the $50-$65 range, hardly anyone even looks at 50° eyepieces unless they say "Orthoscopic" on the side, and each year the number of those reduces.

There is also a significant, and growing, problem with grey market sales here (Chinese retailers/factories selling directly to consumers, bypassing tariffs and importer+dealer profit margins),

which means customers can pick up some famous Chinese brands for 50% less than US prices.

I'm not sure what we'll do about that.

Since the '80s, Vixen has had very little presence in the US market, despite having a 75% share (I've been told) of the Japanese market.

Despite nearly zero advertising, Pentax has done better in the US, despite the parent company, Ricoh, only thinking of the telescope market as a small add-on to their sport optics market share.

It's interesting the differences between the US and UK markets.

Don

44 minutes ago, Carl Au said:

Are you sure they are the same, the Altair version only has 8 elements not the 9 APM claim to have. The Tecnosky also claims to be 75 degrees and not 70. I don’t know what to think anymore, all very confusing 

I have no idea where people get their information.

Prior to an eyepiece's arrival the "specs" are all over the place.

The 30mm Ultra Flat Field from KunMing United optics is a 9 element design and 70.1° apparent field (actual measurement), and is now sold to 8 different companies.

Altair has a cross-sectional diagram:

https://www.altairastro.com/altair-30mm-ultraflat-eyepiece---precision-barrel-stainless-steel-238-p.asp

It shows 9 elements, which is correct.  If their website page for the eyepiece shows 8 elements, it is a simple typo.

Note: the field stop diameters listed on the chart are the iris measurements in the eyepieces and do NOT apply to a calculation of true fields because that is not where the focal plane in the eyepieces are.

The field size dimension in the 30mm UFF is 36.4mm, which is the number you can use for field size calculation.  Likewise, the 24mm has a 27.3mm field diameter, regardless of the field stop shown in the diagram.

In negative/positive eyepiece designs, the field size is NOT the same as the internal field stop dimension, so if you take such an eyepiece apart and measure the iris dimension, you are not measuring the field diameter that relates to true field.

If you want to look at any manufacturer's field stop claim for rationality, try this:

[Eyepiece Apparent Field / 57.296] X eyepiece focal length = field stop diameter  or [AF/57.296]*FL

It does assume the manufacturer is not lying or mistaken about the apparent field, and it can be off by a couple tenths of a mm.

The 30mm APM, at 70.1° translates to a calculated field stop of 36.7mm, but the actual measurement is 36.3-36.4, so you can see the formula can be off a bit.

However, the chart from Altair shows a 30.4mm field stop.  The field diameter calculation shows this cannot be the case, which is where the utility of the field stop calculation can show how plausible the figures are.

In this case, the manufacturer does not specify the field diameters we can use for true field calculations, so we have to measure the eyepieces with a star timing or some other method that is consistent.

Sounds like you could use a "kit" of Barlows: 2x, 2.5x, 3x, and maybe 4x?

My use was on deep sky, not the Moon.  Some people who have used the ES on the Moon report some light scatter.  I did not see that because I did not use it on the Moon.

I thought stars were sharp in both.

The ES required some in travel at the focuser with a few eyepieces.  The TeleVue did not.  If you are near a focuser limit, that could matter.

I think the TeleVue is designed to be parfocal with eyepieces that have their focal planes slightly below the shoulder, like most TeleVue 1.25" eyepieces.

Mechanically, the ES is beefier and might do better with a very heavy eyepiece.  It's quite a bit heavier than the TeleVue, if that matters.

Note: the TeleVue is only available in a 1.25" size, while the ES is also available in a 2" size.

Also, 3X is a lot of magnification, and might result in having the magnification go too high for seeing conditions.  2X Barlows are more likely to be usable a higher % of the time.

In your scopes and with your eyepieces, a 2X would be more useful, though I wonder why a Barlow since you have eyepieces down to 2.5mm.

On 04/03/2022 at 04:21, FLO said:

@Don Pensack I have seen what you do at Cloudy Nights but that isn't how we do things at SGL. As retailers you and I are not unbiased. 

Consider APM - a brand you stock that we do not. You often insert APM into eyepiece discussions. But no eyepiece is perfect. You and I can find weakness in 'any' eyepiece design (telescopes too). So, if I were to join conversations about APM eyepieces and hi-light a "flaw" while mentioning a brand we stock... How is this good?  

In this instance you literally hi-lighted an imperfection in a product that competes with those you sell. See the difference in lighting and exposure between your photos posted at Cloudy Nights. 

I see your conversation there continued for some time while people attempted to find the same aberration in their own eyepieces. Some could, some could not. The conversation ended with a member who owned the same eyepiece saying he could not see the problem. For him, it was a non-issue. 

At FLO we stock and support StellaLyra eyepieces manufactured by Long Perng. I have selected a number for my own use (with a 10" Dobsonian). Over time if I or anyone else notices something that requires attention (i.e. if we find the eyecup consumes a few mm of eye-relief) then we will update our product pages and specification. 

Steve 

Steve,

First and foremost, I'm an observer.  Those two 14mm eyepieces were ones I was unfamiliar with, and I was looking only for myself for an eyepiece of that focal length I could use with glasses.

Frankly, I do not post about eyepieces with sales in mind.  I obtained one of the LongPerng 14mm as a test eyepiece, along with several others (Delos, Nikon SW, Pentax XW, which I found all too narrow for my taste), at my own expense, and not just from my stock.

A couple of the other 14mm I used, I was already familiar with.  These two eyepieces had nearly identical eye reliefs and apparent fields, so I was interested to see what differences between them I could see.

I only reported what I saw.

My comments do not and cannot apply to other brands or other focal lengths of the eyepieces in question, and I did not state or imply that they did.

And you are 100% correct: look closely and there is a flaw in every eyepiece made.  There is no perfect eyepiece.  I even reported on a couple flaws I noticed in the TeleVue Apollo once I bought one of those for my own use and had a chance to use it.

I wish you every success in your endeavors, and long enjoyable nights under the stars.  You do the astronomy hobbyists a great service to support SGL.

I have not tried, nor seen the 68° eyepieces from Long Perng.

And my experience with the 80° is only with the 14mm.  I think Richard (25585) in the UK has used the 20mm as well, which he speaks of highly.

My purpose for getting the 14mm was to find out if it is compatible with glasses.  It is advertised as having 20mm of eye relief, and I believe it does.

However, it has only about 12mm eye relief from the top of the eyecup, which cannot be folded down, and I could not see the whole field with glasses on.

When I removed the eyecup (which just threads off) and replaced it with a rubber eyecup that was only 1/2mm above the aluminum top of the eyepiece, the eye relief was more than adequate for glasses.

Of course, if used without glasses, it would have more than long enough eye relief.

It is very sharp and has excellent contrast and color rendition.  However, my 14mm had edge of field brightening in the outer 5-10° of field.

Since that shows up on hazy nights in nearly all eyepieces, I compared it with a 14mm Morpheus, which I knew, from experience, had none.

And, that night, the Morpheus still had none.

So I concluded the Long Perng eyepiece had two flaws--one fixable, one not.

The mfr admitted they knew about the brightening issue but were working on a correction.  They did not mention what that was.

I would add that it is fairly mild and might be tolerated by many observers.

You can see my post on Tuesday above to see a link to what I think might be the reason.

The eyepiece is very sharp and should be a good eyepiece for any scope.  It worked fine in a friend's f/3.45, so it is well-corrected.

P.S. due to current VAT rules, I do not sell to the UK, so I do not compete with FLO.

If I lived in the UK, I would probably buy from them.  Many posts on this board show they are a reputable company to deal with.

18 minutes ago, cajen2 said:

Sorry, I wasn't clear: I meant in price.

Ah, yes.  Well, there are fewer focal lengths (8 in XW, 9 in Delite, 5 in StellaLyra 80°)

Will Long Perng introduce more focal lengths?  Unknown.

You can see how the 14mm compares to a 14mm Morpheus here:

https://www.cloudynights.com/topic/769375-eofb/?p=11103180

and the following post.

5 hours ago, cajen2 said:

Has anyone had any experience with either of these ranges? They look interesting, though the 80° range is verging on Pentax XW / TV Delite territory.

You mean Delos, not elite.

Actually, 80° is quite a bit wider than 70-72°, and the feeling of field size is that it is a lot larger.

The 80°,  though it has a long eye relief, needs a replacement of the included eyecup to be usable with glasses.

See reviews of the Orion LHD eyepieces.

Without glasses, they're just fine.

On 23/02/2022 at 17:28, Voyager 3 said:

Agreed . Except that the reader has to ignore the comments on the eyecup problems.

There are now reports appearing on CloudyNights and apparently it is very good, so another good eyepiece in the mix.

By the way, I just posted the 2022 Eyepiece Buyer's Guide there.

The brass split ring is placed low in the adapter.  It's possible it grabs on the 1.25" barrel on some eyepieces.

But if it grabs the lip and tilts slightly, it can cause problems with removal.  Some of my customers have had this problem.

I do like the fact the adapter is threaded for 2" filters, and can even act as a camera adapter for cameras with a 1.25" tube by threading directly to a t-thread below it.

It's got some nice features.

But the ring that grabs the eyepiece should have been 15-20mm long, like some Twist-Lock adapters.