Don Pensack

At a higher cost and higher weight, so it doesn't really get to the same point--a 1.25" eyepiece longer than 17.5mm with an ultra-wide field. And Ackermann was only able to pull off a 70° field in that 30mm APM in 2", not 76° . It could be like the 22mm Nagler, but despite a slightly narrower apparent field, the desire for a longer eye relief would increase the size and weight, so you'd be back to Nagler weight and price (maybe a bit less), which again would defeat the purpose. Seriously, a 2" Morpheus with a longer focal length than 17.5mm would be expensive and heavy, so just quite unlikely. Just as there is no 2" TeleVue Delos, or 2" TeleVue Delite. Could it be done? Possibly. At a price and weight the current Morpheus buyer would buy? Probably not.

Not exactly. The US has no national sales tax, so prices here are quoted without any taxes: TeleVue 21mm Ethos--$854, or £615.56 or €725.97 Explore Scientific 20mm 100°--$799.99, or £576.63 or €680.06 [I used the big bank exchange rate because it was easiest to compute.] FLO lists the 21mm Ethos at £810.00, but remember that that price includes VAT. As does the €990.00 price that APM charges for the same eyepiece (€831.93 without tax). Plus, you have additional shipping and importation fees added to the cost, which the US does not. Except now, where ES is paying a 25%+ tariff on the importation of eyepieces, while TeleVue, with no Chinese sources, is not. So the same eyepiece, sent to Europe or the UK will not pay the 25%+ importation tariff that ES pays in the US.

Baz, In this design, I think anything longer than 17.5mm would have to be a 2" eyepiece, so, no, I don't think there will be longer focal lengths. It isn't just about the size of the field stop, it's also about how light is handled in the design. It would have to be fatter, heavier, longer, and a lot more expensive--look at the 31mm Nagler for an idea of shape. It's easy to make an all-positive design with a field stop up to the diameter of the barrel interior (like the 24mm Hyperion), but it doesn't work with a negative/positive design. The lenses above the negative lens have to be significantly larger in diameter or have very complex curves, both of which add price and weight to the eyepiece. You wouldn't buy a 20mm Morpheus if it were 2" and twice as heavy and twice as expensive, but it might need to be. Think 22mm Nagler, for example. Baader has not really gone in for long focal length 2" eyepieces except the 31mm and 36mm Hyperions, which aren't in the same quality range as the Morpheus eyepieces.

Think a 40% magnification progression: 17.5mm>>12.5mm>>9mm>>6.5mm>>4.5mm Now you see the WHY of the focal length progression. the 14mm is the odd man out--the largest focal length in the original internal design. The 17.5mm has a different internal design, which is why it has a different eye relief, focuses at a different place, and a slightly different apparent field. It feels remarkably the same, though, which is a credit to the designers. It took them 3 tries to get it right.

I don't really think so. It just might correspond to an excellent magnification and exit pupil in a lot of scopes. It depends what you're sensitive to. I hate astigmatism, and have very little tolerance for any in an eyepiece. Other people might hate slight chromatic aberration or field curvature, or something else. In Ernest's tests at f/4 (f/10 was much much better--more or less perfect), the star images were: 4.5mm--4' center, 10' 1/2 way, 14' edge largest issue CA 6.5mm--4' center, 10' 1/2 way, 16' edge largest issue CA 9mm--5' center, 11' 1/2 way, 14' edge largest issue Astigmatism 12.5mm--5' center, 12' 1/2 way, 16' edge, largest issue FC 14mm--5' center, 18' 1/2 way, 24' edge largest issue FC. [the 17.5mm was not tested] Note: 10' is essentially a perfect star image, so judge accordingly. If you cannot see the very outer parts of the star images due to light pollution or small aperture, the edge stars drop to <1/2 as large in size. And all of them are pretty much perfect at f/10. It's my impression from testing them at f/7, f/5.75, and f/3.45 that the Morpheus line probably has a minimum f/ratio of 4.5-4.7 for best performance. At f/5.75, the 14mm (the weakest in the test) is pretty much sharp to the edge in a flat field scope, so the f/4 results have to be judged as a "worst case" scenario. Stick to longer f/ratios and the performance is high-end. A coma corrector will work wonders at f/5.5 and shorter.

Magnifications the Morpheus eyepieces produce in my scope and how they work: Scope is 12.5" f/5.75 (the f/ratio with a Paracorr), 1826mm focal length 17.5mm--104x. A good, fairly low power eyepiece for larger objects--frequently used on large clusters. I don't often go below this power because few objects look better at lower powers. 14mm--130x. A popular all-around magnification for many objects. Not high enough for a lot of objects, but seeing never interferes at this power, so it is often used on large nebulae and clusters. My #1 finder eyepiece. 12.5mm--146x. a comfortable magnification for nearly everything large and a frequently-used focal length. I use the Apollo 11 a lot more (166x) because the 11mm focal length is more usable for galaxies. 9mm--203x. THE galaxy focal length, large planetaries, etc. Very frequently-used focal length. Sold my sample, but will acquire another one when they're available. 6.5mm--281x. Not too high. Good for nearly all small objects and good for Jupiter and Moon in average seeing. I use the 6mm Ethos a lot more due to a wider field and MUCH sharper optics. I don't use glasses at this magnification, so the eyepiece needs the eyeguard extender ring. The extender ring also helps block peripheral light, so the eyepiece has excellent contrast. If anyone uses any Morpheus without glasses, I recommend the extender ring. 4.5mm--406x Not used because my 4.7mm Ethos SX has a field 45% wider, which is more useful in an undriven scope. The Ethos SX is sharper and brighter, too. It isn't just seeing, because the 3.7mm Ethos SX is sharper than both of them.

North America smoke map: https://fire.airnow.gov/?lat=34.0778841&lng=-118.491626&zoom=10

TeleVue has a recommendation: https://www.televue.com/engine/TV3b_page.asp?id=103

Way past time to clean the lens.

So add 1.25" to 2" adapters to 1.25" eyepieces to convert them to 2". Because there is no reason for an eyepiece shorter than 14-17mm to be 2" when the field fits in a 1.25" barrel. I like the convenience of 2" eyepieces too but do it by adding adapters to my eyepieces shorter than ~14mm.

I don't know where he got 14mm as the effective eye relief of the 22mm Nagler type 4. I need at least 17.5mm of effective eye relief to see the field stop of an eyepiece with glasses on with that apparent field, and I have no problem whatsoever with that eyepiece with the eyecup in the down position and the eyeguard in its maximum inward position. My glasses touch the rubber, but they don't press hard against the rubber, and the edge of the field is easily seen in peripheral vision. I'd put the effective eye relief at or about 17.5mm. Ditto the 30mm APM UFF, which is even easier to use than the 22mm Nagler. I barely have to touch lens to rubber to use that one. My personal experiences with most of the eyepieces on that list differs by only about a mm from his figures, but a few are way off, differing by 4mm or more from his figure. He has the 17mm Astrotech AF70 at 17mm, for instance. On my sample, the rubber eyecup could not be flipped down, and when it was at its minimum height it put the effective eye relief around 10mm--it was completely unusable with glasses, and only the central 50-60% of the field was visible. So how was the Effective eye relief figure derived? Glasses use? Or subtracting the depth from the top of the eyecup from the mfr's quoted eye relief figure? One thing occurs to me: You may not need as much eye relief to see a narrower field of view. A 10mm Design eye relief on a 16mm 82° eyepiece, for instance, was so tight that seeing the field stop was very difficult. A 10mm Design eye relief on a 50° eyepiece, however, seemed comfortable and easy. So perhaps glasses-friendly eye relief will vary according to the apparent field of the eyepiece. If that is the case, then using ones glasses to gauge effective eye relief may not be an accurate way to measure the effective eye relief. Alas, if that is the case, it also means that knowing both Design eye relief and Effective eye relief may not tell you if the eyepiece is glasses-compatible.

In addition to what Louis has posted, it's important to understand 2 concepts: Design eye relief, which is the distance of the exit pupil from the top center of the eye lens in the eyepiece, and Effective eye relief, which is the distance from the top of the rubber eyecup (when folded down) to the exit pupil. There can be (I've measured) as much as 15mm between these two figures. In essence, one eyepiece could have 20mm of eye relief and be unusable with glasses, while another could have 18mm of eye relief and be very easily usable with glasses. The factors that influence that are: --the flatness or concavity of the eye lens in the eyepiece --the amount of depth to the eye lens in the eyepiece into the body of the eyepiece --the shape of the rubber eyecup and how high it rises above the eyepiece body. One recent eyepiece with a 20mm eye relief has an 8mm tall solid rubber eyecup that can't be folded down, so makes the eyepiece unusable with glasses. It's usable with glasses if the eyecup is removed, but then there is no protection for the glasses from the aluminum top of the eyepiece. --your tolerance for how hard you are willing to press your glasses against the eyepiece. I haven't found an eyepiece yet where my glasses don't at least touch the rubber, but some required a hard press that isn't comfortable after a while. This is why I think about the only way to be sure the eyepiece is usable with glasses is to look for at least 18mm of eye relief, then read reviews of the eyepiece, then try it for yourself. Otherwise, it will be difficult to know. There is some math you can use to decide whether the manufacturer is lying about the design eye relief: Apparent Field of View= 2*Tan-1(eye lens radius/eye relief) The eye relief in the formula assumes a flat eye lens, so if the center of the eye lens is 2mm concave, and the mfr claims a 20mm eye relief, then you would use 18mm in the formula. One recent eyepiece claims a 20mm eye relief and the eye lens is ~2mm concave. It has a 30mm eye lens and a claimed apparent field of 80°. Plugging 18mm of eye relief into the formula gets an apparent field of 79.6°, close enough to 80° to say the mfr is telling the truth. Alas, the eyepiece only has 10mm of effective eye relief, so isn't usable with glasses as is. Had the manufacturer had a smaller eye lens, then you could know they were either lying about the apparent field or the eye relief, or both.

You could try a stronger solvent. A step up from the normal lens cleaning fluids is pure acetone. It's also safe for lenses, but don't let it drip inside as it could dissolve some of the paint on the edge of the lens. The next step up from that is paint thinner, but if acetone doesn't touch it (use cotton Q-Tips), then your supposition that something got on the lens and harmed the coatings could be correct. If it's organic, though, acetone will take it off completely. Note for some viewers: some case foams outgas when a case is kept closed for a long period of time. This stuff can coat the lenses in an eyepiece with hard-to-remove exudate. So ALWAYS store the eyepieces in the case with caps tightly on.

In between those extremes would be the APM Ultra Flat Field 10mm 60° (also available from Altair Astro), a good step up from a Plössl. And the Pentax XW 10mm at 70°, one of the best in that line.

For visual use, and to not make the image too dark and cut out too much of the nebula, an O-III filter that passes both the 500.7nm spectral line (strength of 75) and the 495.9 spectral line (strength of 25) is desirable. Since high contrast is desirable, which means narrow bandwidth, the 493.1nm O-III line (strength of <1) is always excluded. So, what is the optimum O-III filter? To catch both of the strong visual lines, yet still have a narrow bandwidth for better contrast: about 11.5-13nm bandwidth, >90% transmission at both spectral lines (w/94%+ being even better), and close to zero out-of-bandwidth (OOB) transmission in the 400-700nm range. O-III targets: planetary nebulae (e.g NGC7293, NGC246), supernova remnants [some, not all] (e.g. The Veil nebula), Wolf-Rayet excitation nebulae (e.g.NGC6888, NGC2359) My personal TeleVue BandMate II O-III filter has a tested 12nm bandwidth (most current model since 2018), 99.2% transmission at the 495.9 line, and 98.2% at 500.7nm, with OOB <1% anywhere else. My personal Lumicon O-III Gen.3 O-III filter (most current model since 2018) was tested to have an 11.5nm bandwidth with 95.1% at 495.9nm and 94.7% at 500.7nm, with OOB <1.6% anywhere else. The two are virtually indistinguishable in the field on O-III targets. Another O-III filter of note is the current version of the Astronomik O-III (they make the TeleVue filter). With such narrow filters, it is best to use exit pupils of 2.5mm or larger at the scope, and preferably >3mm. Some small and bright O-III targets can be seen better without a filter with exit pupils <1mm, however. NOTE: large hydrogen/helium gas clouds are usually best if the H-ß line at 486.1nm is also passed by the filter. This includes nebulae like M8, M20, M17, M16, M42/43. If the filter also passes the H-ß spectral line, it is referred to as a "narrowband" filter, and these vary from 22-27nm bandwidth. Some good examples: Astronomik UHC, DGM NPB, TeleVue BandMate II Nebustar, Lumicon UHC. It is important to realize that many filters in the market today are much wider than the aforementioned bandwidths. These cheaper (usually) filters do provide some contrast enhancement, but are much less effective at making the nebulae stand out because of lower contrast.

That looks like a smudged fingerprint on the outside. Did you try removing the lower lens and cleaning both sides?

One major disadvantage to an eyepiece that yields an exit pupil of 0.5mm or smaller (0.45mm, in this case) is that the exit pupil is so small that not only is the image very dim, but floaters in the eye can intercept the light and cause those annoying aberrations. You won't view the Moon at small exit pupils for long before the presence of dots, amoebas, bacilli, and arcs that fall in front of the craters become extremely annoying. Keep the exit pupil larger and this is much less of an issue. I such a case, a 6.5mm might be a lot more usable on Moon and planets than a 4.5mm.

What are you looking for? more eye relief? Given your choice of eyepieces, probably not this one. a wider apparent field? This is a good reason to upgrade. You have a LOT of choices. Sharper star images? If you are talking about the center of the field, given your scopes, this may not be a reason to upgrade at all. Possible, but not guaranteed. Better contrast in the eyepiece? Possible, but the dryness and transparency of the air matters more, given what you already own. less chromatic aberration of star images in the outer field? Again, possible, but not guaranteed. a flatter field? This might be accomplished, but if you see no curvature of field (edge and center focus at different points) in what you have, not a good reason to change. a higher light transmission to see fainter stars and more details in other DSOs? Today's eyepieces all transmit within a few %. Sharp differences here are extremely unlikely. less field distortion when panning? Possible, but not guaranteed with other eyepieces. less edge of field brightening? Have you noticed any? If not, be sure to read reviews before buying, or ask on the forum. an easier-to-obtain-and-hold exit pupil? Possible, but not guaranteed. Better color fidelity? Cooler in tone? Warmer in tone? Warmer tone helps on planets and Moon and seeing carbon stars, while a cooler tone may seem more natural. Most discussions of this are "tempests in a teapot". Less internal light scatter? HIGH likelihood of improvement here. But read the reviews. Many higher end eyepieces yield a lot of internal light scatter. So it helps to identify what you want to change before you upgrade. The one place you are sure to see a major difference is if you go to eyepieces with a wider apparent field.

And, neither does the 14mm Morpheus in my scope. Or any of the Morpheus eyepieces, for that matter. I have so little accommodation left, I'd see it if it was there. So, my comment about it being scope-specific.

The Vixen Lanthanum 8-24 zoom was made by a different company than the StellaLyra zoom, and in a different country.

With the Moon that low in the sky, I'm surprised you could differentiate chromatic aberration in the eyepiece from atmospheric refraction.

The 7mm Delite is only 12g lighter and actually slightly larger in O.D. When looking at them, though, they appear similar in size.

The Morpheus is not even closely parfocal with the Nagler. Well, it's about 1/4" apart (the Morpheus is more inward, the Nagler more outward), which is not a really long distance as eyepieces go. My own eyepieces focus over a 3/4" range, which is fairly typical.

I've not used the 3.7mm on the Moon, which is where I'd expect to notice. On Uranus, Neptune, small planetaries and close double stars, I've not noticed any notable level of light scatter. I've only spent about an hour with the two APM short focal length 110° eyepieces, not long enough to have an opinion about light scatter.

John, I think it is actually a 3.6mm. At least that's what Stellarvue measured. If it's 3.55mm, it would depend how you round off as to what you call it. The APM XWA 100° "5mm" has been measured at 4.7mm, 4.77mm and 4.9mm by different testers. It might be wise to call it 4.8mm +/- 0.1mm. Just as apparent fields are rarely exactly as stated, so too focal lengths vary a bit, usually by only 0.1mm which makes little difference in the scope. My scope has over a 1.8 meter focal length, and the difference between 4.7mm and 4.9mm is only a difference of 16x. I doubt I could see that if I tried at that high a power.