This is the final installment of a four part series. Later in the report, I move away from my exploration of high power eyepieces, and go back to my exploration of low power eyepieces, the topic that got me started a year ago. Towards the end of this installment is some commentary in which I explore some of the lessons I have learned from my exploration of my newly acquired 30mm Kasai 90 degree eyepiece.
As always, with every one of my reports, I ask you to give me the benefit of the doubt, take all I say with a grain of salt, and always seek a second opinion if it is important to you.
Darwin Bagley
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Date: Wed, 11 Nov 1998
Subject: Quantum 6 for three hours in snow and frost.
November 11, 1998
I set up my Quantum 6 f/15 Maksutov around 10:00 P.M. Mountain Standard time, in the snow and frost in my backyard. The skies had opened up for me, I could see clouds to the north of the Salt Lake valley and clouds to the south of the Salt Lake valley from time to time, but I was cloud free for the whole three hours that I was out viewing. Despite six layers of clothing, by 1:00 A.M., the cold air was cutting right through to me, so I gave up at that time.
I compared a 16mm UO Super Erfle with a 16mm UO Konig on the Orion Nebula coming over the hill. I also tried a 20mm UO Super Erfle against a 20mm Meade Research Grade erfle. In both comparisons, I found the UO Super Erfles to be a touch more contrasty than their counterparts. The Super Erfles also had stars that were more pinpoint. The University Optics Super erfles make for very good deep sky eyepieces. Just a brief comparison on the Orion Nebula between the 16mm UO SE and my 14mm Pentax XL, and I got the feeling that the 16mm SE seemed to give every bit as good a view as the XL. The XL has more eye relief than the 16mm SE, but the 16mm SE has more eye relief than the 16mm UO Konig.
The 16mm UO Konig in the Q6 had a ghost on Jupiter, which was made more noticable by the fact that the 16mm UO SE was without any ghost. Over the past few weeks, I have been finding the UO Super Erfles to be satisfactory on the planets and pleasing with the moon as well. The University Optics super erfles seem to be good general all-around eyepieces in my telescopes.
For fun, I compared the 20mm SE with my 24mm UO Konig on the Trapezium and the Orion Nebula. I liked them both, and both seemed to have quite good eye relief.
The 16mm power range is not all that useful with my scopes for viewing of Jupiter and Saturn, as I tend to prefer more magnification.
In the beginning, I compared a 7mm Pentax Ortho with a 7mm UO ortho on Jupiter and later Saturn. The seeing and/or cool down was not up to those. It's not saying much, due to poor seeing, so take it all with a dose of caution; but, I did notice a couple of differences. The bands on average seemed a touch more contrasty on Jupiter with the 7mm Pentax Ortho; whereas, the Cassini division and tracking in the murk actually seemed to be better with the 7mm UO ortho. In poor seeing, the 7mm UO ortho focused up easier and felt more comfortable to use for some reason.
People have wanted me to check the coma on the 16mm UO Konig in a slow scope. For stars and star fields, I found that the 16mm UO Konig was just a bit too much magnification for the Q6, as the stars looked bloated. The 16mm SE had more pinpoint stars on axis in comparison, and that was enough to make me decide to sell my 16mm UO Konig and get the 16mm UO Super Erfle instead. The 16mm UO Super erfle works better with my main scopes, as I had already on another night found the 16mm SE to function superbly with my 16 inch scope as well, in comparison to the Konig.
The final hour, after cool down and in better seeing, I went back to compare the 7mm orthos on Saturn at the meridian. It's a toss up. On average, the 7mm Pentax ortho seemed to show the Crepe ring more easily than the UO ortho; but, on average, the 7mm UO ortho seemed to show the Cassini division a bit more easily. None of these results were continuous -- at times the UO showed the Crepe ring just briefly, and there was a long moment where the Pentax really made the Cassini division look nice. In summary, the differences were so small that they all could be attributed totally to changes in 'seeing'. It's going to take a lot more time than an hour to determine which eyepiece is best, along with probably a lot more experience on my part.
I also got the 6mm UO ortho to focus up with the Quantum 6 at 381X on Saturn and show the Cassini division. It looked nice. That's a new high power record for me and that scope on a planet like Jupiter or Saturn. I have at times run the scope on the moon at between 400X and 700X, and I have had luck at times with the Q6 on Jupiter between 254X and 326X. But, we all know that the moon is usually more forgiving of high magnification; and, we also know that most people usually like a little more magnification on Saturn than they do on Jupiter.
In the future, I hope to get a 6mm Pentax SMC ortho in order to compare it with the 6mm UO ortho on Saturn in the Quantum 6.
I then went back to the Orion Nebula and the Trapezium. I was trying to see the six stars of the Trapezium. Of the eyepieces I tried, I liked the 7.5mm Tak LE, 12.5mm Tak LE, 16mm UO SE, 20mm UO SE, and the 24mm UO Konig. I was not able to see all six stars with the Q6, something that is usually very easy in my 16 incher when Orion's out of the murk, unless seeing is plain horrific.
Anyway, I sensed the fifth star of the Trapezium with the 16mm UO Super Erfle with the Q6, but it was only fleeting and only because I knew it was there. I could not sense the other one nearest the brightest star of the Trapezium in any of the eyepieces.
The clear winner of the night was the 16mm UO Super Erfle, as it succeeded in vanquishing it's rival, the 16mm UO Konig. Though the 16mm UO SE is sometimes not as aesthetically pleasing as the huge wide field of the 16mm Konig, I found that, on average, the 16mm UO SE was better suited to my two main scopes. I guess I need to get that Konig to somebody where it will be the best eyepiece with his or her telescope(s).
Darwin
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Date: 15 Nov 1998
Subject: Zeiss orthos vs. Pentax orthos
A very interesting subject, in my humble opinion. I have seen Markus Ludes championing the Pentax Orthos on the internet NEWSGROUP sci.astro.amateur, where he has mentioned doing side by side comparisons between the Pentax orthos and the Zeiss orthos. So far, he is the only person I have seen who has been willing to claim the Pentax orthos to be superior to the Zeiss. He repeatedly mentions on s.a.a. that the 6mm Pentax is noticably superior to the 6mm Zeiss in his opinion.
Some have speculated that he was comparing against the older .965" barrel Zeiss eyepieces that most people are in agreement are not quite as nice as the Pentax orthos. The newer 1.25" barrel Zeiss orthos the majority seem to agree to be the best 4 element planetary eyepieces, though I have heard some say that the old Nikon orthos are superior to the new 1.25" Zeiss orthos. Each person has different experiences, and with all the different scopes out there, they could all be right -- as I have had some eyepieces be the winners in one scope and the same ones be losers in another scope.
The fact that I can get three or four Pentax Orthos for the price of one used Zeiss ortho is the reason why I personally think the Pentax are better.
Another reason why the Pentax line is better in my opinion is the large variety. There are the 4mm and 6mm Zeiss, the only two I would be interested in. There's also the 10mm Zeiss which might be useful for Saturn and Jupiter planetary work with some scopes, but I recently discovered not really necessary for my scopes. The Pentax line has the 3.8mm XP, and the 5mm, 6mm and 7mm orthos in the range I am interested in. The Pentax 'planetary' lines have interim powers.
With my scopes, I like to step up the power knotch by knotch until I find the highest power that the seeing or object allows. Sometimes the highest power for the seeing is at 7mm, and other times it's at 5mm -- or something in between.
With my scopes, there's a big jump from 4mm to 6mm, and from 6mm to 10mm. The Zeiss don't cover the interim powers, and I have discovered lately that many of the 'hardcore' planetary observers have a lot of high power eyepieces so that they can step the power up in increments to find the power that shows the most, given the seeing or the object being viewed. Even at the 10mm Zeiss range, the Pentax has the 8mm XP, the 9mm ortho, and 12mm orthos; so, if someone is needing to step through the power ranges in the 10mm range they can do so better with the Pentax line, as well.
For planetary viewing, I do think the Pentax line can recommend itself solely on the merits of large diversity, if nothing else. Pentax also has the 'availability' factor on its side right now. And, I personally am only interested in the high power planetary eyepieces, as I don't do planetary at the lower powers except on the moon. With the moon, I am one who prefers wide field eyepieces if I am going to be looking at the moon low power.
Anything 14mm and lower power, and I tend to prefer an eyepiece with a relatively wide field of view. I know some prefer their orthos or plossls for low power, but I personally have always been one to reach for a widefield eyepiece.
Just different personal preferences, and nobody is right. You have to find the habits that work the best for you or the things that you like the most.
Darwin Bagley
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Date: Oct and Nov 1998
Subject: Comparisons over the months
Some people prefer 'sound bites', quick and dirty reviews, and one paragraph summaries or one paragraph reviews. This one is for them.
Well, I got to observe for an hour, that always makes me feel good. The UO orthos were wiping the floor of the Tak LE's in my larger scopes; but, last night in the 80mm cheapo scope, the LE's were clearly outshining the orthos. Go figure.
Using an eyepiece during the day in my opinion is one of the best ways to quickly bring out some of its limitations. Darkness hides too much. Jupiter and Saturn can also be brutal tests of optical quality, and some have favorite double stars that they use.
Sometimes sharpness and a good image are much more preferable than a huge wide field, especially if that huge wide field is plagued with coma at the edges. The coma of the 16mm UO Konig ruined the image last night quite frequently, when the eyepiece was used with my fast 16 inch scope at full aperture.
Comparing a 7mm UO ortho with a 7mm Pentax SMC was an interesting test for me. The image was essentially the same. I got the distinct feeling that for the time being with my limited funds, I should concentrate on 'buying the best' at higher powers than 7mm. I am very thankful to the person who loaned me the 7mm Pentax SMC to try in my scopes. I therefore, think the 3.8mm XP and 5mm Pentax SMC ortho are the priority, along with maybe a 6mm Pentax SMC ortho if I can figure out how to come up with the money. That would serve to maximize my planetary performance in my best planetary scope, the 16 incher.
I don't remember coma problems with the 16mm UO Konig in the 80mm refractor nor the f/15 Quantum 6. My complaints with the Konig in those scopes was the lack of enough eye relief in order to be able to see the whole field of view. With the 16mm SE, the eye relief is barely adequate enough to see the whole field of view, so there is not the temptation to get closer in order to see more, and consequently mess up the glass surface with eyelash oil.
The Quantum 6 is NOT as good a planetary scope as the 16 incher; but, I still have visions of long leisurely evenings with the Q6 learning the surface of the moon. The Q6 is more comfortable to use being that I don't have to chase the eyepiece as much with that one.
Surface detail on Saturn at 16 inches of aperture is glorious to behold -- a pretty sight and then add in the rings, beautiful stuff. And, even stopped down, I have more aperture with the 16 incher to use on Jupiter. Again, more planetary flexibility in the 16 incher. Also, the Q6 seems to have residual tube currents all night long at times.
Part of the joy of the hobby is trying to figure out which piece of the puzzle each eyepiece fits.
In a night like last night, in which the seeing is mediocre to poor, I find the 7.5mm Tak LE on Jupiter with the 16 incher to be my most favorite eyepiece. The 7.5 LE shows me shadow transits and the GRS, while I periodically come and go waiting for the seeing to improve. The 7.5 LE is great for the long haul, when I just stand there for half an hour looking at Jupiter. If the seeing goes good, then I am looking for something else; but, while I am waiting it out, the 7.5 LE is the weapon of choice.
Some nights nothing significant happens: Last night was clear and a long observing session with the 16 incher. I didn't make any significant discoveries nor see anything new -- the seeing was horrible. One exception, I found out that the star Rigel in the constellation Orion has a companion -- that's the first time I have ever been able to see the companion to Rigel. The 20mm Nagler along with the 14mm Pentax XL provided some very stunning views of the Orion Nebula, but that wasn't anything new.
The 20mm Nagler does have the least eye relief of almost anything I have except the orthos. It's actual relief is something like 9mm to 10mm. But, for some reason, it's short eye relief is not annoying compared to other eyepieces. The 20mm Nagler is the most comfortable eyepiece to use of any eyepiece with 'inadequate eye relief' that I have used.
Slightly off subject, but in the line of sweets, I call such circumstances, "Matches made in heaven." The 7mm Nagler with the C90 on the moon, with the whole moon in the field of view was such a match. The 40mm 7/70 in my 10 inch f/4.5 showed nebulosity in the Pleiades better than the 20 inch scopes nearby. Every now and then, the symbiosis causes a synergy where the sum is indeed greater than the individual parts.
I have found that while viewing something small like Jupiter or Saturn, that not having to get close to the eyepiece in order to have to see the whole field of view goes a long ways towards making those types of eyepieces more comfortable to use. 4mm orthos for deep sky work is an exercise in frustration though. Also, on the moon, I prefer wide field, so the Konigs and especially the Pentax XL's are my favorite eyepieces for that purpose.
Since then, when I expressed some doubts about the 20mm Nagler, I was able to wander the constellation Orion at the meridian with the 16 incher and the 20mm Nagler in some average seeing. On that night, I was thoroughly thrilled with the eyepiece, especially in comparison to the coma produced by the 20mm UO SE and the 16mm UO Konig in the 16 inch f/4.6.
I, personally, have found that if you can afford to buy the eyepieces and do without the barlow, then the non-barlowed views of orthos do tend to be better on average for planetary viewing; though, sometimes I have actually found the barlowed views to work out better if one can get the right combination of magnification and seeing.
In general, the reason, in my humble opinion, to get a barlow is if you only want to have one or two eyepieces, or can only afford one or two eyepieces -- or if you are looking for higher magnification out of eyepieces that have good eye relief. Many people go with barlows due to the eye relief issue, and I can't argue with that.
In the advertising, the 16mm UO Konig is rated at 65 degrees. In actual measurement, I think it is a bit more, around 67 to 68. In actual usage, due to inadequate eye relief, it seems to come across around 50 degrees of usable field.
Actually, I found having the crisp sharp edge of field of the field stop of the 16mm UO SE to actually be nice. Once one sees the field stop, there is no reason to get closer to the eyepiece -- it helps keep the oil off. Sometimes massive huge field is over rated, especially if the eyepiece doesn't have enough eye relief to take it all in.
The 16 UO Super Erfle is a better eyepiece than the 16 Konig for a fast scope like my 16 inch. Due to coma correction and the consequent sharpness of the stars, the 16 SE seemed like a good move for me. I can't afford everything, so sometimes I have to sell one in order to get something that works better with my current set of scopes.
I viewed for an hour Wednesday night. I got the feeling that night that I have too many eyepieces. The seeing wasn't good enough to take advantage of the high power ones, and so half of my eyepieces weren't needed or didn't get used to advantage.
Your comment is interesting. That's the second time that you have indicated the 7mm Pentax XL to be superior to the 7.5mm Tak LE. I find that interesting. You know, I never compared the two. I have tons of comparisons I can make now, but I am subject to clouds just like everyone else. I have noticed that some nights the 7.5mm LE wins the UO orthos and other nights it doesn't. I haven't figured it out yet, but it might have something to do with seeing or changing scopes or eye relief or some such.
I noticed today that you are selling the 7.5mm Tak LE. Did you get that comparison, and find it lacking? I know the 7mm Pentax XL is a great eyepiece, as I recommended it to you; but, I find with the flimsy focuser on the 80mm f/11 refractor of mine that the XL eyepiece is just too heavy for the diagonal in that scope. I worry about the set screw coming loose and the eyepiece falling off onto the ground, as it has tried to do so a couple of times already. Now I don't use the 7mm XL with the 80mm scope due to weight, but instead prefer the LE's or the orthos. I guess each thing has its place.
Darwin Bagley
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December 18, 1998
I took delivery today of a 2" barrel 30mm 90 degree SUPER WideVue, manufactured by a Japanese firm called Kasai. The design of the eyepiece is smart looking. It looks to be black anodized, with white lettering, with a classy looking aluminum pinstripe around the middle.
The design and shape is basically close to the 30mm Leitz 88 that I borrowed from a friend a year ago. However the upper housing of the SUPER WideVue seems a bit smaller in diameter than what I remember the 30mm Leitz being. My 20mm Nagler is about 1/4 inch longer than the 30mm Kasai SUPER Widevue. The Kasai is about 1/8 to 1/4 inch wider in diameter on the upper housing than the 20mm Nagler. They both have a 2" OD barrel for the focuser of your scope. The Nagler's barrel is contoured, and the 30mm Kasai is not. They weigh essentially the same. I can't tell the difference without scales; but, my best guess is that the 20mm Nagler is slightly heavier than the 30mm Kasai.
The 30mm Kasai came in an insignificant box. The Kasai doesn't have the annoying, dust collecting, leather pouch that the 30mm Leitz came with. Being one who loves dust caps on all his eyepieces, I found the lack of a 2" ID dust cap on the Kasai caused me to shoot off a letter to a friend asking where I can get 2" dust caps.
Holding the 30mm Kasai up to the shop light, I could sense what looked like a couple of specs of dust or paint on the innards. I essentially bought the eyepiece for the widest possible deep sky viewing, at the most optimum magnification in my 16 inch scope for viewing deep sky in city sky glow. Specs of dust on the innards of an eyepiece are potentially annoying if one is viewing the moon or viewing bright daytime objects. I have a 2" 32mm UO Konig and a 1.25" 30mm Celestron Ultima that are good for lunar and daytime terrestrial viewing, so my needs to have the 30mm Kasai be perfect for anything besides deep sky are not that pressing. Though one can only hope that specs of paint on the innards doesn't show up in the focal plane while viewing bright objects. I don't know whether it will be significant or not.
On the shop light, there is definitely some sign of lateral color to the image. Again, lateral color is only annoying on bright objects like the moon and during daytime usage. There are purple multicoatings that take on a yellow orange look right where the incandescent light reflects off the surface. My four year old daughter told me, "There's a rainbow in there." Her description, most likely of the coatings, but also possibly the lateral color that she was seeing while trying to look through the eyepiece.
I didn't have a hard time fitting it into my larger eyepiece case as there was an empty spot just sitting there waiting for it. I am excited to see how it performs; of course, it clouded up today right on schedule!
Darwin Bagley
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December 29, 1998
After some record breaking cold, that sounds as if it wiped out the orange crop in California, we got our 'January' thaw today, here in Utah. Unseasonably warm today -- sweater weather. Had clouds all day, but it cleared off right at sunset. I pulled out my Quantum 6 f/15 (Q6) Maksutov telescope for a look. The scope didn't have time to equalize; and, I also believe, as best as I could tell, that the seeing was also poor -- 190X was too much power for Jupiter, for example. But, it was at least clear for an hour or so, and warm. Had what I think they call a waxing gibbous moon, which was 'ruining' things; however, since the moon was the target of my observations, I guess there wasn't much for me to complain about. It will be on the wane in a week, so nothing like the present to test out some new eyepieces on the moon.
I put in my 32mm 2" barrel UO Konig and focused up. Might as well start with the best; and, for the moon through the Q6, I haven't found anything that I like much more than the low power Konigs. The 32mm UO Konig gives no chromatic aberration on or off axis, and it provides some nice crisp lunar details.
I then put the 30mm Kasai SUPER WideVue into the Q6 on the moon, and in comparison it was disappointing. The craters wouldn't snap into focus, and the image seemed washed out or soft, especially in comparison to the Konig. Through the Kasai, the limb of the moon or the circumference of the moon was surrounded in the purple outline of chromatic aberration, a nice thick band of it. Only on axis did the chromatic aberration disappear, not much help considering how huge the field of view was in the 90mm Kasai, enough to fit the whole moon in there.
With my right eye looking at the inside left towards my nose, I could focus a crater of the moon through the 32mm UO Konig on the left edge of the field, and the crater would remain sharp as I manually moved it with the slow motion controls across the axis and to the right edge. The crater would only lose sharpness as it passed out of the right edge, where my right eye doesn't work as well in the peripheral vision area. Anyway, in the f/15 scope on the moon, the sharpness of the 32mm UO Konig is about as good as it gets, and the color free nature of the Konig makes for a very pretty image. The 30mm Kasai couldn't hold its own against that.
I decided to break things up and went and got my 1.25" 30mm Celestron Ultima eyepiece. It provided the same nice crisp color free view of the UO Konig, with noticably greater magnification. For lunar observation, I am going to be reaching for the 32mm UO Konig or for the 1.25" Celestron Ultima, no surprise there. The surprising thing was that the 30mm Kasai performed on the moon basically as I thought it would, as I seldom get things right when I try to guess in advance -- it seems.
The 1.25" 30mm Ultima has a bit of the 'too close' kidneybean effect, or just a minor touch of spherical aberration of the exit pupil. For my 80mm f/11.4 scope that only takes 1.25" eyepieces, the 30mm Ultima is the logical choice to go with. The 32mm UO Konig has the tunnel effect when getting too close or too far from the eyepiece. I find that overall, I do prefer the 32mm UO Konig with the Q6 on the moon; but, I do like the extra touch of magnification from the 30mm Ultima for that particular scope, as well.
Since the new guy on the block was the 30mm Kasai, I was paying close attention to all the little things. There were a few pleasant surprises with the Kasai, which I will get to a bit later.
The 30mm Kasai has a lot of glass in there. I don't remember eye relief being a problem, but I need to remember next time to put on my glasses and give it a try. While viewing through telescopes, I got into the habit of taking off my glasses a decade ago. My glasses produce annoying ghosts on such things as the moon, and sometimes the specs of dirt on my glasses actually end up visible in the image. I find it best to remove them, so I sometimes am a poor one to remember the eye-relief-eyeglass issue. But, without my glasses, I didn't have problems with eye relief, but I did have problems with my nose getting in the way.
I noticed that with my left eye it was very hard to get on axis with the eyepiece, as my nose kept getting in the way and hitting against the housing. The 30mm Kasai will black out completely if one is far enough off axis, something that is common with many wide field eyepieces. Anyway, my nose must be closer to my left eye, as I had a very hard time getting the left eye on axis so that the 30mm Kasai wouldn't blackout on me.
The Kasai SUPER WideVue has an 'explosion' of light on the edge of field while viewing the moon, which I assume to be reflections off of internal surfaces of the eyepiece; the moon is bright after all. It also has a minor 'purple coatings' ghost way off axis, an image of the corrector plate and secondary reflecting off the internal diagonal of the scope showing up in the coatings of the Kasai; it was not a reflection nor a ghost image of the moon itself. Being that everything takes place at the edge or way off axis, and due to the wide field of the eyepiece, I found the ghost and reflection aspects of the Kasai to not be that big of an issue in actual usage; they weren't interfering with the image of the moon itself.
The 32mm UO Konig doesn't have any of those problems. Someone described the 30mm Kasai as servicable in a pinch for lunar observation. That was my assessment. I went back and played with it a lot more trying to figure out the softness issue. I noticed that as I moved the terminator of the moon right on the axis of the Kasai, that it did sharpen up into a good usable image. Anyway, in my f/15 Maksutov, the Kasai does sharpen up tolerably right on axis, but it softens as one moves the terminator off axis. It has a lack of off axis sharpness for lunar observation, and no amount of work with the focus knob could correct it off axis.
Due to the huge field of view, the explosion of light at the edge of field and the off axis reflections were easily ignored, but the lack of off axis sharpness really got my attention and was impossible to ignore on the moon.
The 30mm Kasai, surprisingly on the moon, seemed to have no kidneybean problems, or NO spherical aberration of the exit pupil. I have a hard time believing it. But, the image was all there or it would completely blackout, but no kidneybeans that I could detect. The Kasai image was there and seemed to stay there once acquired, it was just soft with a lot of chromatic aberration. One of the complaints I read about the 30mm Leitz from time to time is that it has spherical aberration of the exit pupil. I have tried the 30mm Kasai in only one scope, so maybe the kidneybeans will show up in some other scope or on brighter objects during the day. I also remember having problems with dust in the images while using the 30mm Leitz with some of my scopes, something that I don't remember anyone else ever reporting about the eyepiece. Maybe it was only the eyepiece I had, or maybe I was wrong.
A year ago, I didn't like the 30mm Leitz with my scopes on the moon all that much, but I have had people write to me and tell me that I am wrong -- they like their 30mm Leitz a lot with their scopes on the moon. We are all different and we all have different preferences and different telescopes; and I have been wrong on more than one occasion. But, to date, I believe my 32mm UO Konig in the 2" barrel to be the best lunar eyepiece in that particular power range, especially with my scopes.
While viewing the moon with the Q6, the lack of kidneybean along with no visible dust on the focal plane gives me hope that the 30mm Kasai might be tolerable for use as a terrestrial eyepiece. I remember seeing dust in focus with the 30mm Leitz which made that eyepiece annoying to use during the day and on the moon with my Q6. I don't remember well and would have to read my report from a year ago, but I think the 30mm Kasai had less blackout problems than what I remember experiencing with the 30mm Leitz. From memory, I think I would rather have the 30mm Kasai than the 30mm Leitz for lunar with the Q6, but neither eyepiece could beat the color free crispness of the 32mm UO Konig for lunar observation. From what I have seen of the 30mm Kasai, I believe that there is a good possibility that the 30mm Leitz would be a lot sharper across the field of view on the moon.
I have heard that the 30mm Leitz lenses have been mounted in different housings by different manufacturers over the years, and maybe the majority don't have dust in the focused image. I find seeing dust in focus to be very distracting, with any eyepiece on the moon.
Being that I don't have a 30mm Leitz on hand to test in side by side comparisons, my memory is not all that clear as to the merits and weaknesses of the Leitz. Since it's being done out of memory, take it all with a grain of salt, and you can read my Leitz report on Todd's web page to make your own conclusion of the differences and their weight if any. I just remember being more unhappy with the 30mm Leitz on the moon, than what I feel in regards to the 30mm Kasai; the Leitz was unacceptable due to dust and blackout, whereas the 30mm Kasai was tolerable.
Again, from memory on the moon, I liked the 35mm Panoptic I used to own better than I liked the image from the 30mm Kasai. But, again, for lunar observation, the 32mm UO Konig was better than them all, though the 30mm Celestron Ultima 'newcomer' in my arsenal is quite nice as well. And, for the moon, people with more experience than I have are telling me that their Zeiss orthos in the 20mm to 40mm range are the best -- some grapevine hearsay that I have received.
The 30mm Leitz was about the worst eyepiece for daytime and for lunar, and it was the best for deep sky in a fast scope. Being, from memory, that the 30mm Kasai is slightly better for lunar than the Leitz in my Q6, it gives me hope that it would prove to give an adequate second place performance to the Leitz for deep sky. I sold my 10 inch reflector that I used to test the Leitz, and the 30mm Leitz has been returned to its owner. I have a 16 inch f/4.6 now. Being that 16 inches is closer to what I like for deep sky, I am hoping that the 30mm Kasai will come into its own with that scope on some of those deep sky objects and starfields. Time will tell.
I did a few other comparisons. My favorite 'ultra-wide' eyepiece with the Q6 on the moon is my 20mm Nagler. There is some yellow chromatic aberration on the edge of the moon's limb, but I find yellow a whole lot easier to ignore than the purple halo that the 30mm Kasai was producing. On the moon, the 20mm Nagler appears to give a clean crisp image across the field of view. A nice eyepiece or at least an adequate eyepiece for lunar observation.
I also stuck in the 14mm Pentax XL to get a feel. It too is very nice. There is an infrequent 'too close' kidneybean that I get from time to time with the 14mm XL on the moon with the Q6; however, the eyecup put into the proper position keeps me far enough away so as to avoid the kidneybean look for the most part.
All of these eyepieces I mentioned, I preferred them for lunar observation with the Q6 over the image presented by the 30mm Kasai. Pretty much right on schedule for a 30mm ultra-widefield. With the moon on the meridian, and high cirrus moving in, I fought the urge to pull out the 16 incher so as to finish it.
I must exercise patience. I want to wait for waning moons or new moon before trying to see if the 30mm Kasai can do the job that I think it was designed for -- open clusters and starfields with a large aperture fast telescope. I hope it proves to be as good as what I remember the 30mm Leitz being for deep sky work.
Darwin Bagley
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January 5, 1999
I got out my 16 inch f/4.6 telescope and set it up. My goal was to try the 30mm Kasai SUPER WideVue on a variety of deep sky objects. My hopes were quite high, as I figured that the eyepiece would work very well with a fast scope, just because an eyepiece with a 90 degree field of view begs for a deep sky application.
I was very disappointed. For pinpoint stars and color correction, my 2" 32mm UO Konig was vastly superior. For coma correction and aberration correction, my 40mm 7/70 UO Konig was vastly superior. And, my 20mm Nagler was vastly superior for pinpoint stars throughout the whole field of view.
With my 16 inch f/4.6, the 30mm Kasai performed on deep sky just like it did on the moon with my f/15 Maksutov. In the fast 16 inch f/4.6 scope on the Orion Nebula region, the bright stars at the outer thirty percent of the field of the 30mm Kasai were prismatic clam shells. Not only is the eyepiece poorly corrected for edge of field, but that lack of correction also takes on the features of chromatic aberration. Only the central 10 percent (20 percent if one wants to be kind) of the field, right on axis, is the eyepiece any good at all -- just as well go with an ortho.
I can't remember being so disappointed with an eyepiece. I thought a bit of cool down along with a tweak on the collimation might improve things -- hardly. After my best attempt at collimation, I tried wandering through some star fields. The stars of any importance at the edge of field had the appearance of planetary nebula in my peripheral vision.
The 30mm 88 degree Leitz that I tried a year ago was detectably superior to the Konigs (32mm and 40mm) for edge correction and coma correction in my old 10 inch f/4.5 scope. The 30mm Kasai in my 16 inch f/4.6 telescope was noticably and undeniably inferior to anything that I could find to compare it against for the Orion Nebula region and for the star fields I tried it on.
Now for my usual disclaimers. First, the eyepiece I received might have been a lemon or might have been improperly assembled. If they are all like the one I received, then the news will get out and people will learn to avoid the eyepiece; one eyepiece in a couple of telescopes hardly makes for a complete assessment of the subject.
Second, I don't have a coma corrector. The 16mm UO Konig that I tried in this scope performed almost as poorly for edge correction and coma problems, though not so for chromatic aberrations; so, I know from experience that some eyepieces can indeed have a very bad time coping with my 16 inch scope. However, I expected the 30mm Kasai to be on par with the 32mm and 40mm Konigs, along with the 20mm Nagler. The Kasai is not.
I figure that my only hope of getting satisfactory performance out of the 30mm Kasai with my 16 inch scope would be to purchase a $250 2" barrel coma corrector. If I do that, I might have a chance of getting some usage out of the eyepiece. But, that will only serve to help eliminate the Kasai's only real advantage over the 30mm Leitz, the price advantage.
Third, there is indeed the possibility that I was expecting more out of the eyepiece than what it is capable of, and that could potentially be clouding my results in some way; maybe for the price, I shouldn't be expecting it to perform like a Leitz.
Barring the ever present possibility that I ended up with the rotten apple of the bushel or the possibility that I don't know what I am talking about, I feel confident that my money would have been better spent on a 27mm Panoptic or a 28mm Pentax XL; in fact, I feel like the 32mm 2" barrel UO Konig is a much better deep sky eyepiece.
There was one good aspect to the 30mm Kasai that I ended up with; it is extremely well corrected for blackout problems. You just step up to it and the image is there. Quite nice for deep sky. In contrast, I have to work a bit with the 32mm UO Konig to get the eye in the right spot. It's just too bad that 85 to 90 percent of the stars won't pinpoint in the 30mm Kasai.
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I gave the Kasai and the scope three hours to cool down. I tried it again with the same results. Just take the Trapezium the smallest bit off axis, and the four stars of the Trapezium are no longer pinpoints. I imagine that a coma corrector would make the Konigs and the 20mm Nagler perfect with the scope; but, all I believe a coma corrector could do for the Kasai is make the eyepiece tolerable, if coma is the root problem.
Maybe the Kasai was not designed with a fast scope in mind; but, it is not the answer to the 30mm Leitz with my two scopes. Nothing changes the performance of an eyepiece like changing the telescope that it is used in; but, for my scopes, the 30mm Kasai is not what I was looking for.
The 16mm UO Konig was one of the best eyepieces I have ever had with most of my scopes, just not enough eye relief; however, the 16mm UO Konig was 'horrific' for coma in my 16 incher, whereas the 16mm UO Super Erfle was great with the 16 inch scope. The new owner of the 16mm UO Konig, who has a different scope, describes the 16mm UO Konig as potentially the best eyepiece out of any that he owns with that particular scope. The worst in my current scope is the best in his scope, and maybe that's the answer to the 30mm Kasai. A disappointment in my scopes, but it may be fine in some others. Who knows? I guess I am trying to think up some explanation to account for my disappointment.
From what I have seen, those with the 30mm Leitz eyepiece are better off with that eyepiece. They don't have to feel too sheepish about the $1000 that they spent, though some of them may have some scopes that the Leitz doesn't work well in, for all I know. For myself, I can't visualize myself spending $1000 to $1500 for a single eyepiece; though tonight, I wish that I had that kind of money, as I would like to get a 30mm Leitz and pass the 30mm Kasai onto someone else who might have a scope that it is more suited for.
In hind sight, it is rather surprising that the 30mm Kasai would have so many aberrations in an f/15 telescope like my Maksutov. I just thought that it was 'overly' corrected for fast telescopes; but, after using it in my fast telescope and finding no correction for anything at all, I didn't know what to think.
The 30mm Kasai I received is just not doing what I purchased it to do, and that's disappointing.
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I went back out and tried all my more expensive deep sky eyepieces looking for coma with my 16 inch scope.
7mm XL
10.5mm XL
14mm XL
20mm Nagler
32mm UO Konig
40mm 7/70
It was clear to me that the eyepieces above would benefit from a coma corrector; but, the coma had to be looked for in order to see it. It didn't detract from the image and was ignorable. With all those eyepieces above being acceptable with the 16 inch scope, it became quite clear that the problem wasn't with the scope per se, but that what I was seeing was some sort of limitation in the 30mm Kasai.
The coma was so severe in a 16mm UO Konig that I had, that it actually ruined the images of the 16 inch f/4.6 scope at times; so, I sold the 16mm Konig to a friend who doesn't have coma problems with his scopes. There was no way that I could ignore the coma problems with that particular eyepiece in the fast 16 inch scope.
The same appears to be the case with the 30mm Kasai. The coma (if that's what it is) is immediately apparent and very severe; it ruins the image, and is not ignorable. Maybe it would take a quality coma corrector to make the 30mm Kasai usable with my scope; but, I was trying to get the right collection of eyepieces so as to avoid having to get a coma corrector.
The thing that disturbs me as much as anything is that I experienced the same lack of off-axis sharpness with the 30mm Kasai in my slow f/15 Maksutov; which makes me wonder if there is something wrong with the design besides coma.
Darwin Bagley
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January 7, 1999
I checked with the previous owner of the 30mm Kasai, a person I trust, and I was told that I got the pick of the litter of about ten Kasai 30mm eyepieces. According to him, some did have problems, but not mine. So, my theory about it being a defective eyepiece has been disproved. The eyepiece is what it is.
I was also told that people using 10 inch and 11 inch f/10 Schmidt Cassegrain scopes have been getting some satisfactory usage out of the 30mm SUPER WideVues that have been sold, including the one I received. The 30mm Kasai sounds much like my experience with the 32mm UO WideScan. If the 32 WideScan was matched to the right scope, it was some people's most favorite eyepiece. If the 32 WideScan was put into the 'wrong' scope, the results were less than favorable. Some consider it amazing that the 32mm UO Widescan works at all for anyone.
It kind of sounds like the same applies to the 30mm Kasai. Apparently, it has to be matched with the right scope in order to get the best results. If that is the case, then it is probably not quite as versatile as the 30mm Leitz.
As far as I know, I am the first person in the United States (and maybe the world) to try a 30mm Kasai in a fast f/4.6 telescope with lots of aperture. Until I came around, nobody knew that a 30mm Kasai was going to exhibit problems with a fast light bucket. The previous owner of the 30mm Kasai certainly didn't expect me to get the results that I got with my 16 inch f/4.6.
The 30mm Kasai has been generating a lot of curiosity. I shared parts of my previous review with the handful who have asked. One commented that any 90 degree eyepiece in the 30mm range is a miracle. He described the fact that the 30mm Leitz works at all, to be contrary to all the laws of physics. The Zeiss stuff is put together with much more exacting standards, so that it has the greatest chance of succeeding; but, there probably shouldn't be a 30mm 90 degree eyepiece in this world, if one gets right down to it. That's not exactly what he said, of course, I am just paraphrasing what I got out of his conversation from my own point of view.
Another friend, an optical designer, was actually wondering how much Mr. Kasai lost on the manufacture of the 30mm Kasai SUPER WideVues. How's that for a different point of view? Apparently it is very expensive to put together a 30mm 90 degree eyepiece, even using the cheapest of parts. Over the last decade, I have heard rumors of Al Nagler saying that a 30mm or 32mm 'Nagler' would have to sell for around $2000 or more in order for Al to make a profit, even under mass production. If memory serves, my optical designer friend has spent $4000 or more to have similar 'specialty' eyepieces designed for exacting applications over the years.
One of my friends told me that I should be very angry and try to get my money back. I am not angry. With eyepieces you win some and you lose some, that's the nature of the game. No eyepiece is the complete and total solution to everyone's problems. Yes, I am disappointed that the eyepiece didn't work well with my scopes, but I have learned that it's no guarantee that the eyepiece will fail with all scopes. Nothing changes the performance of an eyepiece more than to change the scope with which it is being used. However, from my limited experience, I don't think the 30mm Kasai is as versatile in as many scopes as the 30mm Leitz or the 32mm UO WideScan would be; but, I may be wrong.
The last month I have seen reviews of the 30mm Kasai on the internet from different people. I had a hard time believing that they were using the same eyepiece that I have. Maybe theirs is better than mine. Maybe I am more thorough in my reviews or more picky about what I like. Or maybe I have a different scope. But, at times, I think simple one paragraph 'pie in the sky' reports regarding any subject do more harm than any good that they do; but, that's just my opinion. Some of the reports I have seen on the internet regarding the 30mm Kasai are more thorough than others, and I do feel that the more thorough reports were indeed the more useful. As far as I know, I am the first to report any severe problems with a 30mm Kasai -- maybe there is something wrong with me.
One of my friends suggested to me that he has doubts that a coma corrector would do anything at all to help the eyepiece; but, from my point of view, I figure I won't really know until I have tried.
For myself, I know that in my fast telescopes, I got better results out of the Paul Rini eyepieces, and for less money; except the 30mm Kasai has the best control over the blackout issues of any eyepiece I have ever tried in that power range. Of course I could be wrong on that as well, or your mileage might vary.
At this point in time, I am curious to borrow a coma corrector and see if it helps the 30mm Kasai or just makes things worse. The 30mm Kasai is an interesting curiosity; and, I still think it looks nice, the way the glass has been mounted. But, a little caution is recommended as with any eyepiece -- it may not work for you.
Darwin Bagley
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SUMMARY:
That's what I love about people in this astronomy hobby; they each have a completely different way of looking at things. Over the past decade, I have talked to dozens of people at the local star parties, and over the past two years I have corresponded with a couple dozen people on the internet. With some of these topics, I can ask each one of these people the same question and get 100 different answers or opinions. Some would say that they can't all be right; but, from what I know about some of these people and some of the topics I have discussed with them, I would say at times that they can indeed all be right -- at least from the point of view of their own personal circumstances.
They each have different telescopes. They each have different eyepieces. They each have different likes, different preferences, different technical backgrounds, different budgets, different friends, and different opinions.
In this astronomy hobby, sometimes I think I have discovered an 'eternal truth' whenever I discover that a handful of people actually agree on a subject. When I talk to people in person and they ask me for my opinion, I sometimes see their eyes glaze over, and I know that they have a different opinion or a different set of experiences. Some have the courage to share their opinion; others don't. Some with 30 years experience will flat out tell me that I am wrong, even though their opinion of 30 years contradicts what a couple dozen other people have told me.
If I correspond or talk with a person long enough about the hobby, they will eventually tell me something that just doesn't match with my personal experiences. I have also found that over time my opinions change; it seems like I am always proving myself wrong. The hobby is infinite in its variety. I am sure that my opinions don't all correspond with your experiences, and maybe they never will; though given enough time you might find yourself in agreement with me, only to discover that I have changed my opinion.
And there you have it. You now know what I have been doing since the last time I checked in. Take it all with a grain of salt, as mine is only one opinion; and, in the overall scheme, I don't have a lot of 'personal experience' to draw upon, so I could easily be wrong.
Best of luck to you all, in your journey of exploration.
Darwin Bagley