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Comparing Two Wide field Constellation Binoculars- Orion 2x54mm versus Kasai 2.3x40mm
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Comparing Two Wide field
Constellation Binoculars
Orion 2x54mm versus Kasai 2.3x40mm
I sat on the fence a few years before I decided to step off and gamble my money on these wide-field, low power Galilean binoculars. I've never been impressed with any sort of Galilean telescopes, field glasses or opera glasses and I suspected that they were just an expensive, trendy gimmick; but based on others' comments and experiences, I considered that these specialty items, with their wider than typical fields, might actually fill a niche in my astro-equipment arsenal.
In a nutshell, after trying them I found that yes, they do. I was truly surprised and impressed with how well a modern re-vamp of the Galilean system can perform.
Are they a replacement for my 7x35 wide fields, 8x42's or 12x50's?
Absolutely not! But they have their use and here's why:
I am a little bit near-sighted and have a small issue seeing at distance in low light conditions. In daylight my eyesight isn't bad enough to need correction according to the FAA medical examiner nor the driver license folks and I am perfectly happy with my uncorrected distance vision. But at night the stars are a little swollen and dimmer stars fade to invisibility. Therefore some amount of correction would be nice when looking at the night sky. I do not have nor want to deal with regular eyeglasses because the hassle/benefit ratio isn't worth it to me and I certainly won't deal with eyeglasses when using a telescope. But with their added magnification (though slight) these little binoculars tip the ratio in their favor. They provide that slight distance correction to sharpen up the stars with the added bonus of a magnitude boost which my aging eyes need. (My pupils don't dilate as much as they did when I was younger.) These little binocs allow me to see many more stars than my naked eyes (or eyeglasses) and many more satellites too! So that is the niche that these little Galilean field glasses fill, and they do it nicely.
The question remains, which of the three popular models is best for me? I chose to try two models which I considered to be the top end and the bottom end of the performance scale based simply upon the advertising literature. Here are the specifics of each:
WIDEBINO 2.3x40mm (28-degree advertised true field)
Kasai Trading Company, Tokyo, Japan. Cost: $155
This unit came in a very nice padded, nylon, zippered case. The eyepiece dust caps are fair. The objective dust caps fall off with a simple tap. I tossed them. I hate fumbling with binocular dust caps that aren't a single unit secured by the neck strap (like my Nikons have). The included nylon neck strap keeps the unit hanging with the objectives conveniently against the chest to keep them warm and dew free. The unit itself looks and feels to be of very good construction, with a solid dual center hinge. The individual focus eyepieces are smooth and easy to turn but it is also easy to accidentally defocus them. As they hang around the neck the eyepieces stick out pretty far and are the easiest parts of the unit to grab. Trying to grab them by the objective barrels usually results in bumping the eyepieces anyway, so I just hold them by the eyepieces. In daylight this isn't near the problem as when they are used on the night sky when focus is the most critical.
Eye placement is very critical for good focus. Setting the inter-pupillary distance accurately is a very necessary first step. Thankfully, the hinge is stiff enough to keep them where you set them. There is very little eye relief if you want to see the full field so I seriously doubt that anyone wearing eyeglasses could use these as effectively as those without. With my facial geometry, I need to sort of shove the rubber-covered eyepieces into my eye sockets to get a clear focus, therefore I was concerned about eyelash grease getting on the lenses, but the small eye lenses are recessed and fairly well protected by the eyepiece mechanical geometry. With extended use the eyelashes eventually win though. Cotton swabs and cleaner deal with that.
With my eyes under a moonlit sky and incomplete dark adaptation, they easily take in the entire hourglass of Hercules. They take in Bootes from the top of the ice cream (Nekkar) to the tip of the cone at Arcturus which is about 23 degrees. They can't quite make the stretch from Denebola to Regulus, but very close. They reveal many more stars than my eyes alone.
The literature mentions that the field of view increases with the diameter of the eyes' pupils. It is very easy to demonstrate this phenomenon by counting the visible slats of a nearby picket fence as day turns to dusk then turns to night. Considering that even in very dark conditions my almost 70-year-old pupils dilate to only 4.5mm, I'm very happy with the field of view rendered. By the way, the clear aperture of the eye lenses is about 8mm which will accommodate the advantage of younger eyes.
Orion 2x54mm Ultra-Wide Angle 36 Degree. China. Cost: $180
This unit also came in a very nice padded, nylon, zippered case. In fact it is identical in every way to the Kasai case. It seems extremely unlikely that they came from different factories. Even the included cleaning cloth is identical. The neck strap has more width at the neck than the one supplied with the Kasai and all four dust caps fit securely. This unit looks and feels to be of excellent quality construction. The inter-pupillary adjustment and the focus adjustments are much stiffer than the Kasai unit, but that is not a bad thing - at least in moderate temperatures. I did not put them in the freezer for a cold-weather lubricant test. Accidentally knocking them out of focus just doesn't happen.
These 54mm glasses are bulkier and heavier than the little 40mm Kasais, giving the hands a bit more to grasp. It is natural to grab the unit by the objective barrels. The eye lens aperture is a generous 18mm and I found that precise eye placement and inter-pupillary adjustment with this Orion unit isn't nearly as critical as with the Kasai unit. I don't have to scrunch the eyepieces into my eye sockets to see the majority of the field and I suspect that these may be much easier for the eyeglass wearer to take advantage of than the Kasai.
Interestingly, I can see the difference in magnification between the 2.3X Kasai and the 2X Orion. I didn't think 15% would be that noticeable. It is not significant but it is there and frankly, I prefer the slight extra power of the Kasai. The big difference between the units is the field of view which is very significant. The Orion trounces the Kasai in that regard. At dusk, the Orions are noticeably brighter too.
Even at dusk before complete dark adaptation, the Orion takes in Procyon and Castor (about 27 degrees) without breaking a sweat. The Kasai struggles to make it from Procyon to Pollux even after dark. In the dark, the Orions will not only reach from Denebola to Regulus but all the way to Subra. You get the whole Lion.
Another item I might mention: The Orions, with their wider view, at dusk can give an almost "fisheye lens" effect when panning up and down near the horizon. This may be an issue for those who tend to airsickness. However on the night sky with the absence of nearby terrestrial reference points there is no issue.
The Orion unit appears to have a little more attention paid to baffling, and the edge correction is vastly superior to the Kasai. Galilean telescopes certainly do not "snap" to focus, but the Orion unit comes closer to a snap than the Kasai unit, which is visually a bit mushier. In the dark, the Orions show stars to be pinpoints across most of the field. With the Kasais I find myself constantly fiddling with the Focus, trying to get any pinpoints at all - even at center.
I feel like if the Kasai unit were a telescope eyepiece, it would be a .965" from an old Asian import, whereas the Orion unit is more like a modern 1-1/4" or even a 2" eyepiece. Or perhaps the difference can be compared to the jump from a 60mm refractor to a 6" Newtonian.
Aesthetically, the Kasai has more of the "opera glass" feel to it, while the Orion has more of the "binocular" feel to it. The Kasai is the nicely upholstered, compact and maneuverable Volkswagen; the Orion has the raw power and positive response of the Highway Patrolman's Crown Victoria.
The Kasai is smaller, lighter, more ergonomic in some regards and frankly, more elegant than the Orion. The edges of the eyepieces are rubberized and the barrels have a tapered section that prevent them from pinching your nose even if set to a smaller inter-pupillary distance than mine which is fairly narrow - about 63mm. The Kasai's, I think, would work better for children whereas the Orions might not.
The Orions are claimed to accommodate an inter-pupillary distance of as little as 58mm, but that doesn't tell the whole story. Their eyepieces are shorter and the objective barrels are squared off and blocky at the point which, unfortunately, is right where the nose goes between them. When set to my 63mm distance they actually cause discomfort in use and prevent me from getting the eyepieces completely up to my eyes. In cold weather that cold metal is going to hurt! However, to spare the nose a bit of bruising and get the eyes a little closer it is possible to set the inter-pupillary distance just a bit wider than my 63mm because the generous 18mm eye lenses of the Orion product are very forgiving of this. In fact, they do pretty well for me when set to as much as 68 or 70mm. My nose certainly appreciates it!
It is very disappointing that the Orions are not tapered at that nose contact point like the Kasais are. It would certainly make them more enjoyable to use for those with narrow-set eyes and/or big nose bones. If you have both of those anatomical attributes, I recommend that you try them before you buy them!
So, which of these units do I like best?
Both! The Kasai unit is cute. Even though the Orion unit surpasses it in the clarity and field of view departments, the Kasai unit is lighter and smaller and fits comfortably about anywhere you want to put it, and it does a decent enough job on the night sky without pinching my nose. The 15% greater magnification is a plus. It was the first one I played with for a couple of weeks before the Orions showed up and it was my first love, convincing me that this kind of product is worth having around. But when compared to the Orion unit I think it will better serve as a sports glass, or perhaps a backup unit tucked into a corner of an eyepiece case. It works pretty well as a sort of terrestrial "night vision enhancer" around the yard too.
Which would I keep if I could only have one?
Sorry, Kasai. Performance trumps comfort under the night sky and the night sky is the whole point. Orion wins. I'll take the big block V8 over the whiney VW any day of the week, especially for only $25 more in cost. But your mileage may vary.
- NinePlanets
- Mark Strollo, ddastro, CeleNoptic and 21 others like this
58 Comments
As mentioned earlier in the thread Orion was just branding them, they weren’t unique to Orion. You can still get the SkyRover version which is identical.
Good to know 😎👌
Sky Rover makes them and you can find them under Omegon's brand.
They are. The are actually made by Sky Rover but you can find them under Omegon's brand
I love the Orions I have. When I use them, the slight magnification bringing out more stars, but still a wide field of view. Reminds me of how it was looking up at the night sky as a kid with better eyes than me now, decades later.
Years ago, I had a pair similar to the Kasai. I did not like them because I could not wear my eyeglasses when viewing through them. The conical eye settings did not allow me to wear my eyeglasses. Without my glasses, the view was terrible. I dislike astronomy gear like this that seems to be designed for people who don't wear glasses. DON'T ASSUME! I couldn't wait to sell them.
About a year ago, I bought a pair of the Orion. I'm able to keep my glasses on while viewing through these. Much, much better!
The Orion does not pinch my nose. My nose is relatively narrow at the bridge and I do not have deep-set eyes.
For practical reasons, I reject any binoculars of any type which do not allow me to keep my glasses on.
So now, in my opinion, there are three Orion products that will be missed:
- ST80
- ST120
- 2x54 binos
I'm glad I have all three.
Mike
I own the 2x54 under the Omegon brand. I bought them because I was hoping that I could see some more stars under my Bortle 9 metropolitan sky. Well, obviously that was a bit naive, because as the review says, light pollution is a problem with their aperture.
At first I would regret spending money on them but I have since learned to love them. I enjoy sweeping the nightsky with the when I travel to darker skies. Checking on T CrB over the summer has been so easy with them.
So, yeah, they are a bit niche but they complement every setup nicely.
Thank you for the well written review.
I just recieved the 2x54 from Sky Rover Optics for $127
Well made and crisp view, I can't wait to get a clear night.
I got mine last week and after a few nights out with them I have to say that they are a blast to use. Just enough magnification to make out M33, M31, and lots of OCs in Cassiopeia, sharp and bright and, best of all, no hand shake visible. I keep these in the pouch on my belt and keep my Canon 12x36 IS on a strap around my neck and they make a great combination.
FWIW, I notice that they are now out of stock, so I’m glad that I got them when I did.
Edited for typos.
Until recently, I haven't been keeping track of the DSO I've seen with my 2x54's. So far, my "official" observations through these binos have been:
- M31
- NGC 457 (ET Cluster)
- M39
- M13
- M15
- Double Cluster
- Melotte 20
- M34
- M45
- Hyades
- Collinder 39 (Coathanger)
It'd be interesting to keep a running tally of which DSO can be seen through these.
Mike
I saw M33 with them a few nights ago, but on some nights I can see M33 unaided. On that night, they made the difference.
The magnification is only 2x on the 2x54's. Many DSO that can be seen with them will probably only be detected as a spot of light. No structure seen at all. So, it will be a matter of comparing the star field through the binos with what you see on a chart. For this, I would use SkySafari on a smartphone. Hold the binos in one hand, the smartphone in the other, while comparing the star field and chart.
Mike
Nice list. Can you add some info on the condition under which you use them (Bortle scale etc.). That would be extremely helpful to get an idea of what's possible for others.
I viewed these DSO from my yard, which is Bortle 4-4.5. So, not super dark like some spoiled observers enjoy, but also not super light-polluted like I suffered at my previous home.
When the Moon leaves the sky again, I'll try some others.
By comparison, I've observed 268 DSO with my Canon 10x42 IS binos. The aperture is less than the 2x54's but the magnification is five times greater. I don't think I'll be able to detect and verify all those 268 DSO with the 2x54's. At any rate, it should be a lot more difficult due to the lower magnification.
Mike
City dweller here, so super light-polluted skies for me. That's were the 2x54 let me down a bit. I thought I could get more out of them from my home base.
Do love them whenever I travel, though.
Worth noting are the Vixen 2.1x42 binoculars, likely the actual first manufacturer of these which then got copied by Kasai, or Orion or some combination.
I believe you can still find them, it's worth the extra cost for good glass, around $200 usually.
These are a secret to observing from the city, and they act as finderscopes for your binoculars. I enjoy using in bortle 8 and of course under dark skies as well. Some people get DIY glasses attachments even and they're great for reclining. The Galileo style lense and dual eyecup focus takes patience to get to use, and don't expect panorama optics, but it's worth it when you nail the focus and have an entire constellation reveal itself in one view.
I would say the opposite. I use these purposely under Bortle 8 since it lets you see what is not visible a little better, which is useful then to orient your next binoculars for closer views in a spot your body and head is already turned to so you don't lose the spot. Of course the Vixen 2.1x42 pair I use are great under dark sky too.
Yes, that was the reason I bought mine, to actually see the stars in constellations that are washed out from my light polluted back yard.
I can also vouch for the SkyRovers, excellent binos.
Just for what little it might be worth, please allow me to say that I had one of the well-built and optical sound original Russian 2.4 x 50s a few years back and used them once and only once! There are 3 reasons for that, namely:
1.] because I live in a city with plenty of light pollution, with a limiting magnitude diminishment to about mag. 2.5 - 3.0 with the naked eye, while the glass was only able to go roughly 1 magnitude deeper than that, which was probably because;
2.] any two-eyed -- since these things aren't actually binoculars -- optical system with such HUGE exit pupils is wasted on old farts like me who have only a ~5mm ocular optical system. That means that my eyes can only take in about 1/25th of the actual total light output of these glass! In fact, even if I could somehow dilate my pupils to 8mm, -- which would require either breaking in to an ophthalmologist's office for dilation drops or, worse still, taking a hefty dose of LSD, neither of which bad options seem to me like games worth the small candle of improved depth throughput to me using glasses like these -- I would still only be able to take in 1/4th or so of the total light output! ... and
3.] At least for urban, suburban, and exurban dwellers, almost ANY pair of real binoculars, -- you know, those things that have prisms inside them -- will blow away the performance of any of these, to my mind totally GIMMICKY huge exit pupil devices. [If you don't believe me, have a comparison look yourself. Take out, say, that old pair of 8x24 Nikons or Pentaxes that you use for hiking trips and A/B them with any of these 2.3-3.0 X 42-50mm devices and see which performs better. Relative limiting magnitude for binoculars is largely approximated by the old magnification X square root of objectives diameter rule of thumb. So those older binocs would have a relative sky depth penetrating power of 39.2. A 2.3 X 50 glass, by contrast, would have a power of only 16.3, -- only three times better than a 5mm naked eye! -- and that of course assumes that you could use all of the latter's vastly oversized exit pupils, which no human ever could!
In sky penetrating power magnification makes a big difference! For example, I currently have a pair of Canon IS 18x50s, and not only do they blow away gimmicky things like 2.3 X 50 glasses, with their relative sky depth power ratio of 127.3 they even quite noticeably better my older Canon IS 15x50s with a sky power measure of 106.
One last point, if you DO decide to buy one of these big-eyed monstrosities, you can certainly get them for much less than $180. In fact, Ali Express, and no doubt other online optics discounters have very similar products selling for around $45-55. But caveat emptor on those too! If you don't like them, it may be a hassle to ship them back to China, whether by "slow boat" or hyper-fast maglev trains, which latter you will need to wait maybe five more years for, since Chinese engineers are still deciding how best to get their next generation of still faster hypersonic trains to cross on top of the Pacific Ocean. [Take that, you 50 mph limited, AMTRACK! The only purpose YOUR trains seems to be to shine a bright light for all the world to see just how far behind China this country has allowed its transportation infrastructure to fall.]
Alas, I am teetering on the edge of politics so I will end things here!
This statement is wrong. These are Galilean telescopes, not Keplerian, and therefore their exit pupil is virtual and inside the telescope. The objective diameter has nothing to do with the exit pupil size. Instead, the entrance pupil of your eye is magnified by the magnification of the telescopes. The objective diameter of a Galilean is related to the field of view, and that's why they are so large in the design to provide the large field of view.
DVexile is correct.
The whole point is field of view - not brightness, which is a very slight bonus.
"The objective diameter has nothing to do with the exit pupil size."
Hmm?? In that case why can't I buy a pair of 120mm binoculars with an exit pupil of only 5mm and a nice widefield low magnifying power of, say, 6X? Those would certainly be a gas to use for all kinds of applications! But as I learned when I first got interested in optics as a kid of 12 or so, such binoculars, with optical systems capable of actually "concentrating" their light cones cannot be built. For ANY optical system, one can only lower the magnification at the expense of increasing the diameter of the exit pupil. Thus the binocular system just described, which has very large 120mm objectives, could only render a power as low as 6x with an exit pupil of 20mm -- since 120/6=20. This is simply an optical limitation we must all live with. Thus, despite what you may have heard or read elsewhere; "The objective diameter has EVERYTHING to do with the exit pupil size."
"The whole point is field of view - not brightness, which is a very slight bonus."
Well, yes, we certainly all love an ultra-wide virtual field of view, and one can purchase -- generally very expensive binoculars that have apparent fields of up to around 80+ degrees. Such binoculars will also provide significantly more"brightness," i.e. total light throughput, than a regular non-wide field glass of the same magnification. In fact, low power ultra wide field binoculars, with exit pupils up to around 7mm gain their amazing characteristics by being able to take any small region of the view and render it as bright as is physically possible.
This is why, mutatis mutandis, a 14x50 binocular, although it may have up to 2x the resolving power of a much more common 7x50 binocular, can, by the laws of optical Physics, never be more than 1/4 as bright per region viewed as the latter. Should one then step up to a 28x50 binocular, the resolving power could almost double again -- although in practice 1.5X is closer to the mark -- but the brightness would drop to 1/4 of the 14x50, and a mere 1/16th of the original 7x50s! 10x50 and 12x50 binoculars thus still make good sense to mass produce, since they have exit pupils of only 5mm -- for us now visually-challenged old farts -- or ~4.14mm respectively.
The aforementioned 14x50s, with exit pupils of only 3.57mm could, and do, also perform very well with higher resolution images still bright enough to satisfy for most purposes. That binocular size is, however, considerably rarer than the 12x50s, 10x50s or 7x50s. That probably has more to do, I would assume, with the simple fact that 14x binocs, with whatever diameter their objectives may be, are invariably quite difficult for most people to hold steady enough with their hands alone to be profitably used.
If one has ever viewed through a cheapo "ultra wide field" designated binocular, one will generally notice immediately that the image is considerably dimmer, and far less satisfying to view, than it is through any reasonably well-built binocular of similar power. Thus "brightness" is not "a slight bonus," but an absolutely essential component of any superior binocular.