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Denkmeier Binotron-27 on F/6 Dobsonian: First Light

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#1 NeutronStar79



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Posted 11 July 2019 - 12:14 AM

Denkmeier Binotron-27 for Newtonian - First Light on the Moon and Gas Giants

Hello everyone,

I have just received my new Binotron-27 which I purchased after giving it much thought considering the high price tag. I'll say this right from the start: if you can afford them, they are worth every penny.

I had my first light with them last night, the seeing was good, and I had such a great experience that I woke up wanting to share it with the CN community, also in case it can be of assistance to those on the fence as to whether to start binoviewing.

I used the Binotron on an 8 inch F/6 Dobsonian with a pair of TV Nagler T6 13 mm.

My targets were the Moon, Jupiter, and Saturn.

The Unit

The Binotrons arrived in a nice hard case with room inside to hold two pairs of eyepieces and other stuff like filters or other accessories. The case contained, aside from the binotron, a collimating tool (which I didn't need and is not really indispensable for collimation) and a detailed and clear instruction manual.

I skimmed through the manual just to understand the basic functions and how to operate the Power Switch. The sky was clear but clouds were approaching from afar, so I postponed the full reading to later and got right on to business. I just sank the unit into my focuser, locked the Naglers (which was super easy) and pointed at the Moon. The Power Switch was set to mid-power (x2.3 of what your eyepiece would yield without it) by default, giving me about x183, but the seeing was pretty good so I cranked it up to high power, with a x3 multiplying factor which yielded a magnification of about x276 on my setup. Focus was easily achieved without having to tweak with the Middle Newtonian Spacer, which can be easily used to adjust the length of the unit to reach focus if needed. Collimation was perfect right out of the box, but the unit can be collimated if necessary and the instructions manual does a great job at explaining the process. I didn't go thru it but it seems quick and straightforward.

The whole thing isn't even that heavy to be honest. Definitely less heavy and cumbersome than I expected. I used a 500g counterweight and tightened a bit the clutches on my Dob and I had no problems. Of course, it's not like using a single eyepiece, but it's totally manageable.

The Viewing Experience

I have been a visual observer for about three years by now. I've enjoyed looking at planets with a number of different high-end eyepieces. Last night I was literally blown away by looking at those targets with the Binotron-27. Now a word of advice: I am far less experienced an observer than many folks here, so mine could also partly be some form of novice enthusiasm, but I have seriously never enjoyed planetary observing as much as I did last night with the B-27.

The views were just superior under so many respects. The veiws were crisp and clear. The Moon was huge, I felt like I was hovering over its mountain chains. I concentrated on the Appennine Mountains and the general area of the Apollo 15 landing (one of my fav parts of the Moon) and it was just so different looking at it thru the B-27. It felt so much bigger and I could see more details. It also looked more three dimensional. I made comparisons by changing the B-27 with an Ethos 10 mm first and a Nagler Zoom 3-6mm and they just didn't give the same results. I mean the views were great, but once I observed the area with two eyes there was no going back to monoviewing. It's - pardon the pun here - a completely different planet! I showed the difference to my brother who had looked through a scope maybe twice in his life and he agreed the binoviewing experience was far superior.

Jupiter though was what really left me awestruck. I didn't think one could see so much detail through visual observation. The GRS was so big and well-defined and visible, and the shadow of one of the moons (I didn't check which one it was) was so black and visible on the upper (lower in my dob) part of the planet! It must be the ability of our brain to better process these details when two eyes are used instead of one. The festoons on Jupiter were so well defined too. And the planet was just so much bigger than I had ever seen it before. I must have looked at it for an hour (in this regard, my new Geoptik Nadira astronomy chair really enhanced the experience!).

Same for Saturn. It was struck by its size compared to monoviewing. The different colours of the various parts of the planets, from the poles to the equator, were well discernible. The Cassini Division was great. Titans and a couple of other moons hoovered around the planet with a real 3D effect.

The larger aperture of the B-27 compared to cheaper units allows the full use of the 82 degree AFOV of the Naglers, leaving the planets in the FOV for a good time before having to nudge the scope even at high magnification.

One last word about Russell Lederman from Denkmeier: I contacted him for some info on the B-27 because I'm having a 12 inch Dob being built at the moment and he replied to me in an hour. He was helpful and he is a very kind guy.

Conclusion: I don't think I will go back to monoviewing when it comes to solar system targets. Binoviewing is just far superior to it and so much more comfortable. The B-27 are simply outstanding, albeit admittedly very expensive. But with the power switch you essentially just need one pair of eyepieces. Two if one really wants all ranges of magnification for deep sky and planetary. With my 200/1200 Dob, I think a pair of 24mm in addition to my two current 13mm Naglers will be perfect. I haven't tried deep sky yet but I will as soon as we start approaching New Moon in 10 days or so.
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#2 Eddgie



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Posted 11 July 2019 - 06:14 AM

Thank you for sharing your experience.


The sensation of seeing things larger when using two eyes at the binoviewer vs how it looks with one eye is an often reported one.   I would guess that is is simply due to the enhanced visual acuity offered by using both eyes.  Most of us can probably relate to going to the doctor's office and asking to view the chart with one eye and struggling to read a line, but then opening the other eye and reading it easily.  My own right eye is has a defect in the cornea but if I use my left eye, which is good, but then open my right eye, even though my right eye has that defect, I can still see distant things more sharply than if I just use my good left eye.  The brain processes out imperfections from between the eyes and "Stacks" the data to build the best possible image.


And yes, the Binotron is a great piece of gear.   I have owned everything from inexpensive Burgess to Mark V, and I constantly champion the power switch binoviewers (and the B27 is the best of these) as being the best solution for binoviewing.   It works with all telescopes and having three powers with one pair of eyepieces will spoil you so badly that you may never be able to go back to a binoviewer where you have to constantly change eyepieces.


You can spend a lot of money on other binoviewers with all kinds of special OCS types of setups and a case of eyepeices and just never achieve the same user experience as with a good power switch system.


It sounds like are happy with your decision!   

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#3 NeutronStar79



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Posted 11 July 2019 - 07:41 AM

Yes, I'm happy as a clam about that purchase. My 12 inch F/5 should be ready in less than three weeks and I look forward to seeing how the B-27 works with that.

If I manage to stay awake tonight until the Moon sets I'll try them on a few deep sky targets. I'm quite curious to see how they work on M13, and actually for that I might not even need moonless sky!

#4 Jeff B

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Posted 11 July 2019 - 10:38 AM

Welcome to the bino-view world Neutron!


And it's not just newbie enthusiasm, I get it too.


Jupiter with it's moons, especially when they are close to each other, can give a decided 3D effect, as though Jupiter is an actual ball you can look around and the moons appear in front of or behind the planet....or each other (!).


I love the Denk stuff too, and like Eddgie, encourage the use of the power switch system, even with off label viewers (like those from Denis Levatic) with special adapters.  Russ is great and a very, very, clever man who knows this stuff up one side and down the other.  I can certainly recommend "Neutral" pairs of his 32mm Plossls and 21mm LOA's.  Both are excellent eyepieces in their own right as "Neutrals".





#5 REC


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Posted 11 July 2019 - 11:17 AM

So you are "hooked" not a bad thing. My first notes on viewing the moon with my BV where " the only way to view the moon"! Saturn was my next object was Saturn that night. Between the rings and the moons and planet, I did get a 3D effect I thought.


Star clusters at low power really jump out at you. Try M27 and 57 next with a nebula filter and watch them float among the stars. Later in the year when the double cluster and M42 come out will also impress you!

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#6 NeutronStar79



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Posted 11 July 2019 - 10:48 PM

Thanks REC,

I definitely look forward to the nebulas, and in particular to M42. That should be quite a treat!

#7 rob.0919


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Posted 14 July 2019 - 08:01 AM

Nice report. I'm glad you are enjoying your new binoviewers.


Although i don't have the B27, i use a 'sister system' -  the Earthwin Newtonian binoviewer, which is basically the older Denk 2 bino.

I went for the Earthwin as it was a bit cheaper, and also has a combined powerswitch / filterswitch.


The powerswitch magnifications are a bit lower, which is what i wanted ; i get 1.2x 1.9x and 2.4x


I can really recommend a pair of 24's as well ; my Panoptics are IDEAL for binoviewing, giving me 60x - 90x - 120x (approx)

which is pretty much as good as it gets for wide angle, low power, rich field two-eyed viewing with a 12" mirror.


+1 for great service from Russ at Denk and Bill from Earthwin.

Both are supremely knowledgeable and just great to speak to and deal with / order from.

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