18 replies to this topic

[revans]

Due to recent tree trimming along power lines in my neighborhood by the power company I have a larger view of landscape features roughly a couple of miles away (actually about a mile as the crow flies).  The slope of a rocky hill near an abandoned granite quarry has a painted feature known locally as the "Rock" which high school students paint each year with the number of the current graduation year and plenty of adjacent small graffiti.  I used this as one target to observe from my 2nd floor deck using these three binoculars.  A second target was near the "Rock" and consists of a non-painted natural surface of dark flat sloping rock studded with bushes and with some manmade debris scattered on it.

 

I used all three binoculars mounted.  The Astrolux was a little problematic being mounted via it's special bracket on my Manfrotto 804RC2 photo tripod because the eyepieces don't extend far enough out and my mouth and teeth and chin hit against the tripod mounting head with my eyes properly positioned in the eyepieces.  This did not happen with the Oberwerk 20x80 Explore on the same tripod.  The Oberwerk BT-82 45 was mounted on its Oberwerk TR3 tripod with twin pan handle mount head.

 

I recently completed a detailed collimation of the 20x80s and I can say that they are very well collimated.  So is the BT-82.  And naturally, the Astrolux was perfectly collimated right out of the box.

 

So.... what conclusions did I draw.  The Astrolux showed me no small detail that the 20x80 failed to show.  Handheld the Astrolux has a nicer field of view than the 20x80, but mounted on the Manfrotto 804RC2 tripod the 20x80s were much more pleasant to use.  The smallest feature I could reliably identify was on a rocky surface near the "Rock" and consisted of a small white old picket fence about one foot high and broken in many places.  All features of this were plainly visible in the Astrolux and the 20x80s at a distance of something close to a couple of miles away. 

 

The Oberwerk BT-82 outperformed both the Astrolux and the Oberwerk 20x80s using a pair of Explore Scientific 24mm eyepieces for 18.75x.  These revealed much finer detail not even suspected in the other two binoculars.  And when I exchanged the 24mm eyepieces for a pair of 6.5mm eyepieces for 70x the amount of new detail went off the charts at the expense of a little bit of dimming of the field of view.

 

Rick

[fishhuntmike]

This is why I personally feel that if I am going to stand/sit behind a tripod mounted straight thru bino, it might as well be my BT70 due to the improved performance and comfort. In this configuration (tripod-bino grab-n-go) I dont think my little BT70 is much different in effort. My straight thru binos need to be used alone or braced to fit a reduced effort level and greater freedom the BT70 cant. Lack of neck flexibility is a contributing factor for me though and weight isnt.

[BUDSBOY]

Now do this same comparison (with the correct mount for the Nikon) on a clear/dark night.

My Honda sports car is terrible in the snow compared to my Ford truck.

[revans]

Now do this same comparison (with the correct mount for the Nikon) on a clear/dark night.

My Honda sports car is terrible in the snow compared to my Ford truck.

Yes, when the sky clears out from under all these clouds and this rain.  The big surprise for me was how incredible the BT performed compared to the two straight through binoculars (mounted), even at about the same magnification.  And it isn't Oberwerk's best model... it is "only" an Oberwerk BT-82 XL ED and not an SD. 

 

Rick

[RobertoG]

I wonder what helped the 82bt reveal more at 18.5x that the 20x80 couldn't reveal. Is it the ED glass or the better eyepieces, something else maybe?

[revans]

I wonder what helped the 82bt reveal more at 18.5x that the 20x80 couldn't reveal. Is it the ED glass or the better eyepieces, something else maybe?

I can't be certain.  The Oberwerk BT-82 XL ED has FK-61 glass I believe.  The Oberwerk 20x80 ES is considered an entry level binocular and as far as I know it is a basic achromat.  Also, my Explore Scientific 24mm eyepiece pair likely is superior to the eyepieces in the 20x80 ES.  

 

Although a more basic and entry level type binocular than the Astrolux, the 20x80 ES do have the advantage of a bit more aperture and 96% transmission and slightly higher magnification.  Apparently the physics of this keeps them roughly on a par, to my eye at least, with detail visible in the Astrolux in this particular comparison today.  Obviously the Astrolux are a better binocular but size matters as well to some extent I guess.

 

Rick

[DaveL]

The BT has a 5.5 focal ratio which is much more forgiving of aberrations. The straight through binoculars are probably between F3 and F4.

[fishhuntmike]

The BT has a 5.5 focal ratio which is much more forgiving of aberrations. The straight through binoculars are probably between F3 and F4.

Yes its probably the combination of F5.5 vs ~F4, ED glass and premium eyepieces. My BT70 seems to outperform (day and night) my 15x70 explore, Fujinon 16x70 and Nikon 18x70 BUT at the expense of twice the weight or more, much less convenient size and lack of handholdability. On a tripod I'll choose the BT70 when size, weight and space are not an issue. When traveling it can sometimes be an issue. Not at home for me. When hiking forget it all together.

Edited by fishhuntmike, 18 May 2025 - 02:33 AM.

[revans]

I solved the positioning issue using the Astroluxe on the Manfrotto 804RC2 with the Nikon adapter.  The curve of the neck of the adapter has to point back toward the eyepieces as shown in my photo below, otherwise your face will make contact with the mount head when you position your eyes into the eyepieces.  

 

 

Rick

[gwlee]

Rick,

 

I am enjoying reading your comparison of BT to conventional, straight through binoculars for astronomy and long range terrestrial viewing. For several years I have been using 70-92mm refractors equipped with a high quality AMICI prism for the same purposes.  However, I found myself using the refractor less and less, and handheld binoculars more and more, so the refractor and most of its paraphernalia went to new homes recently.

 

I kept the Manfrotto 475B tripod that had been under the refractors and purchased a Manfrotto NT608 fluid head when it went on sale for $300. At the moment, I am using the 475B/NT608 combo under my Nikon 7x50 SP, but want use it to experiment with larger conventional binoculars and perhaps one of the smaller BTs as a possible replacement for my refractor, so look forward to reading more about your findings. 
 

Gary

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Edited by gwlee, 18 May 2025 - 03:43 PM.

[revans]

Rick,

 

I am enjoying reading your comparison of BT to conventional, straight through binoculars for astronomy and long range terrestrial viewing. For several years I have been using 70-92mm refractors equipped with a high quality AMICI prism for the same purposes.  However, I found myself using the refractor less and less, and handheld binoculars more and more, so the refractor and most of its paraphernalia went to new homes recently.

 

I kept the Manfrotto 475B tripod that had been under the refractors and purchased a Manfrotto NT608 fluid head when it went on sale for $300. At the moment, I am using the 475B/NT608 combo under my Nikon 7x50 SP, but want use it to experiment with larger conventional binoculars and perhaps one of the smaller BTs as a possible replacement for my refractor, so look forward to reading more about your findings. 
 

Gary

It seems to me that at a certain size point it becomes necessary to mount binoculars rather than depending on handheld use.  I think for me that happens at or above 4.5 lbs weight, 20x magnification without IS, and 80mm aperture.  And if you have reached these limits then you might as well use a BT rather than a straight through binocular.  I have three BTs with the smallest being 82mm.  I don't see a big advantage only disadvantages to using anything larger and I think a 70mm BT might be fine.  There is nothing wrong with a 100, 120 or 127mm BT but the inconvenience of use, for me, outweighs the gain in what you can see over the smaller sizes.

 

The Astrolux 18x70 is an interesting binocular because it sits at the border zone between handheld and mounted.  I think it is the largest binocular you can really use handheld and not regret it.  I haven't had a good night session with it because of clouds and rain being the main weather pattern since it arrived.  In daytime, for long distance landscape views, it gives a very richly colorful and very three dimensional view that is very sharp.  The view is much more appealing than using my Oberwerk 20x80 ES but at the same time the advantage is mostly aesthetic, and I can't say that I'm missing out on small details using the 20x80ES.  The field of view is just prettier in the Astroluxe.  It seems to function in a sweet spot that the Oberwerk 20x80 ES can't quite find.  But if I have to be mounted, then I'd rather use my BT-82 XL ED than either of these straight through binoculars. 

 

If I have to choose between my smaller Oberwerk 15x70 ES and the Astroluxe 18x70 for handheld use, then I can't and I have to take both of them outside with me.

 

Rick

[gwlee]

It seems to me that at a certain size point it becomes necessary to mount binoculars rather than depending on handheld use.  I think for me that happens at or above 4.5 lbs weight, 20x magnification without IS, and 80mm aperture.  And if you have reached these limits then you might as well use a BT rather than a straight through binocular.  I have three BTs with the smallest being 82mm.  I don't see a big advantage only disadvantages to using anything larger and I think a 70mm BT might be fine.  There is nothing wrong with a 100, 120 or 127mm BT but the inconvenience of use, for me, outweighs the gain in what you can see over the smaller sizes.

 

The Astrolux 18x70 is an interesting binocular because it sits at the border zone between handheld and mounted.  I think it is the largest binocular you can really use handheld and not regret it.  I haven't had a good night session with it because of clouds and rain being the main weather pattern since it arrived.  In daytime, for long distance landscape views, it gives a very richly colorful and very three dimensional view that is very sharp.  The view is much more appealing than using my Oberwerk 20x80 ES but at the same time the advantage is mostly aesthetic, and I can't say that I'm missing out on small details using the 20x80ES.  The field of view is just prettier in the Astroluxe.  It seems to function in a sweet spot that the Oberwerk 20x80 ES can't quite find.  But if I have to be mounted, then I'd rather use my BT-82 XL ED than either of these straight through binoculars. 

 

If I have to choose between my smaller Oberwerk 15x70 ES and the Astroluxe 18x70 for handheld use, then I can't and I have to take both of them outside with me.

 

Rick

When the atmosphere is steady enough, I enjoy using a conventional mounted binocular for long range terrestrial use, but I have never enjoyed using the same combination for astronomy. It’s just too uncomfortable on my neck when looking up. This leads me to believe the best one-binocular compromise might be the largest conventional binocular that I am comfortable using handheld from my ZGC to replace my 7x50 SP.

 

From long experience doing it, I know a 10x50 would work for me in this role. From experience using an 8x56, I am reasonably confident that a 10x56 would also work. What I don’t know is how much larger in aperture and higher in magnification I can go. 

 

How do the 15x70 ES and 18x70 compare for CA (lateral and on axis) for long range  terrestrial viewing in daylight? Which is easier to use handheld?

Edited by gwlee, 18 May 2025 - 04:37 PM.

[revans]

When the atmosphere is steady enough, I enjoy use a conventional mounted binocular for long range terrestrial use, but I have never enjoyed using the same combination for astronomy. It’s just too uncomfortable on my neck when looking up. This leads me to believe the best one-binocular compromise might be the largest conventional binocular that I am comfortable using handheld from my ZGC to replace my 7x50 SP.

 

From long experience doing it, I know a 10x50 would work for me in this role. From experience using an 8x56, I am reasonably confident that a 10x56 would also work. What I don’t know is how much larger in aperture and higher in magnification I can go. 

 

How do the 15x70 ES and 18x70 compare for CA (lateral and on axis) for long range  terrestrial viewing in daylight? Which is easier to use handheld?

Using the Astrolux 18x70 the past couple of days, I have noticed a very pale bluish ghost-like fringe along some brilliant white architectural features such as parts of a church steeple.  This is also present using the two Explore series Oberwerk binoculars that I have.  As far as I know all three of these are achromats.  I don't see it in my Oberwerk BT-82 XL ED during daylight observing,  but it is present as a thin rim around a gibbous or full moon. 

 

Rick

[gwlee]

Using the Astrolux 18x70 the past couple of days, I have noticed a very pale bluish ghost-like fringe along some brilliant white architectural features such as parts of a church steeple.  This is also present using the two Explore series Oberwerk binoculars that I have.  As far as I know all three of these are achromats.  I don't see it in my Oberwerk BT-82 XL ED during daylight observing,  but it is present as a thin rim around a gibbous or full moon. 

 

Rick

Thanks

[Mark Y.]

Very nice report and it's always fun to get a new binocular.That bunch is fabulous....but....C'mon! You know you like your O.B. 15x70 Deluxe the best. 

[revans]

Very nice report and it's always fun to get a new binocular.That bunch is fabulous....but....C'mon! You know you like your O.B. 15x70 Deluxe the best. 

I don't see much difference between the performance of the Explore and the Deluxe but 1) the Explore is lighter to handhold and 2) the Deluxe has the look and feel of a more expensive binocular (which it is).  But I've been using the Explore more lately because it is easier to hold for longer periods of time.

 

This morning I took out a spotting scope I bought last year and haven't used much.  It was one of the last things I bought from Orion before it closed... an 80mm variable angle 20-60x spotting scope called the Grandview.  I put it onto the same subject matter as I'd been viewing in the past few days with the binoculars (i.e. the "Rock" and adjacent landscape).  I used the same photo tripod. 

 

This spotting scope has never really caught on with me although as spotting scopes go, it isn't bad.  The zoom magnification feature is nice but the apparent field of view is claustrophobic.  I think that is why I use this scope so little.  It will show more detail than 15-20x binoculars to the extent that I can read graffiti on the "Rock" that I otherwise couldn't.  But the experience overall isn't very satisfying largely because of the narrowness of the field of view.  So, I switched to using my SV48P 90mm achromat with 500mm focal length, mounting it on my Oberwerk fork mount and Manfrotto 161Mk2B tripod.  I used a 45 degree erecting prism and then a 45 degree mirror diagonal with 25mm, 14mm and 6.5mm eyepieces.  It was a better experience than the spotting scope, but the 6.5mm eyepieces didn't produce a crisp view with this scope when they had done so in my BT-82 with its 450mm focal length. 

 

Using the BT-82 is a quantum leap forward because you get both a nice apparent field of view (depending on the eyepieces chosen) and as much magnification as you could want.  Plus the sharpness is much more crisp and the colors richer than the spotting scope or the SV48P provided.

 

Rick

[sevenofnine]

The Oberwerk 20x70EDU should be in this shootout  I wonder how it compares?

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Edited by sevenofnine, 21 May 2025 - 08:05 PM.

[revans]

The Oberwerk 20x70EDU should be in this shootout  It would be interesting to see how it compares.

rsz_img_2148.jpg.

Well, that was the choice.  I ended up picking the Astrolux and they are probably too similar to buy both.  I expect they are more similar than different with regard to the views they give.

 

Rick

[wrighty338]

Mounted, the BT sounds favourable. Of course you can mount the Astroluxe and Explore, but you can't really unmount the BT for hand held.