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Denk Binotron rollout

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#1 MikeBOKC

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Posted 31 December 2012 - 09:17 AM

Saw an item in the February Sky and Telescope on this new system from Denk . . . looks like quite the upgrade for them! It does not appear to be out to retailers yet, but apparently can be ordered direct from Denk.

http://deepskybinovi...splay&catego...

#2 Jim7728

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Posted 31 December 2012 - 10:09 AM

Dang! Why was I not informed of this sooner? :rant: :grin:

Just bought a TV Bino-vue, but may have gone for the Binotron. :thinking:

#3 Eddgie

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Posted 31 December 2012 - 10:45 AM

Very nice looking unit. I Looks like they have partially emulated the Maxbright in the Collet area.

Curious to see what the normal retail price will be, but it looks like they have a great new product.

I am not a fan of the power-switch type units, and in particular, would like to know if they will allow mating to the Baader prisms for those that need a short light path.

And of course how much the bino head itself will be sold for.

#4 mich_al

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Posted 31 December 2012 - 02:03 PM

I am not a fan of the power-switch type units,

What don't you like about them? I'm trying to wade thru the info needed to buy some binoviewers.

#5 Eddgie

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Posted 31 December 2012 - 02:40 PM

In low power mode, the powerswitch caused aperture reduction in both my EdgeHD 8" and my C14. It is almost impossible to use any kind of reducer together with Binoviewers in an SCT and not loose any aperture, and the loss with the Denkmeier was extreme in both scopes. Far more than I can tolerate.

And the high power arm resulted in a power that was too big a step from the straight though for my tastes.

So, I found the low power arm induced aperture loss to be totally unacceptable, and since the jump to the high power arm was just too big, I found myself using intermediate powers which required a lot of eyepeice changing.

There is no way to get any meaningful focal reduction using binoviewers in an SCT without accepting aperture loss.

If someone using an SCT is willing to accept that though (and many are) then I think the supersystem is an easy way to change powers. To me though, if one is willing to accept a smaller apeture, why not just get a smaller telescope that has a wider field to begin with?

#6 Denimsky

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Posted 31 December 2012 - 03:00 PM

To me though, if one is willing to accept a smaller apeture, why not just get a smaller telescope that has a wider field to begin with?


Still you get the full aperture with the other two power factors. Am I right?
Then the power switch system is still useful and convenient.

And you lose aperture with the reduction arm but this power isn't available without the reducer anyway so what do we lose here?

For me, Binos without power switch system is a deal breaker. It is too much hassle for me to switch two eyepieces. Especially it is quite dewy here that I live and it is even more difficult to switch them with dew strips involved.

#7 Denimsky

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Posted 31 December 2012 - 03:04 PM

I'm just wondering if I need to upgrade my super system.
If I plan to, I should act quickly otherwise my super system will not worth anything soon :smirk:

#8 johnnyha

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Posted 31 December 2012 - 04:23 PM

I go along with Eddgie I am not a big fan of the PowerXSwitch. But if that thing has a T2 connection up front, I'm interested. Kudos to Denkmeier! This will set the bar for the new ES binoviewer that is being discussed.

#9 DaveJ

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Posted 31 December 2012 - 04:47 PM

...But if that thing has a T2 connection up front, I'm interested.


Congrats to Russ Lederman at Denkmeier for the new binoviewers, but I don't see anything at all on the linked site to indicate it has anything at all resembling a T2 connection. As a matter of fact, I highly doubt it - but I'm hoping I'm wrong on that.

#10 Eddgie

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Posted 31 December 2012 - 04:52 PM

Hey, what works for you works for you, but it didn't work at all for me.

The question was asked what I didn't like about them and I answered. And I was clear to say that others might not be bothered by this, but it bothers me.

I sold my C11 to move to a C14, so I don't see any great desire to turn my C14 back into a C11.

But again, this is me. It might be fine for everyone else, because everyting is a compromise in one way or another.

So, I just answered the question that was asked and did not suggest that everyone else was wrong for doing this. It just did not work at all for me personally.

If others are willing to accept the reduced contrast and brightness (which is already being reduced by the binoviewers themselves) then that is great by me. They get to look through their telescopes and decide what is best for them, and I get to look though mine and decide what is best for me.

#11 Denimsky

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Posted 31 December 2012 - 05:05 PM

Eddgie, I'm not saying that you don't have valid point and I respect your opinion because I know you are a very knowledgeable person about optics.

What I like to know is that the Denk II still loses the aperture for the other two magnification factor (not the reduction arm is used): I think it is 1.2X and 2.8X.

If it doesn't lose aperture with 1.2X and 2.8X, 0.66X is just a bonus with some compromises.
If it loses the aperture all the time, that seems a serious problem.

So that (is it losing the aperture for 1.2X and 2.8X) seems to be more useful information than the fact that the power switch loses aperture used with the reduction arm used.

#12 johntrob

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Posted 31 December 2012 - 05:39 PM

Some people look at it as raw, dead fish (bait) others see it as sushi.

#13 GlennLeDrew

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Posted 31 December 2012 - 06:03 PM

Intriguing, indeed! I really like the new user collimation system; about time! I've long advocated for the inclusion of no-tools collimation in all binocular equipment, as I've been doing for my own home-made gear since '96.

Clearly, at least one manufacturer out there has been paying attention to forums like this, where the incessant bleating of the herd about merging issues can't be missed.

#14 mich_al

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Posted 31 December 2012 - 07:58 PM

Eddgie
Thanks for the input. I'm finding binoviewers have more of a learning curve than many other things.

#15 bcuddihee

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Posted 31 December 2012 - 09:20 PM

I did run a light protection test on my c8 with the power switch and the reducer reduced effective aperture to a hair over 6 inches. Straight through I was measuring around 7-3/8 effective aperture, the mag mode showed almost no aperture reduction. Just my results and in no way difinative other than that it did substantiate the effect of the power switch in the reduction of aperture. In addition...with the reduction of aperture with the CO being a constant, the CO percentage increases as well. Hope this helps.

#16 Paul G

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Posted 01 January 2013 - 09:42 AM

In the S&T review didn't they note that the power switch introduced some optical aberrations?

#17 Eddgie

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Posted 01 January 2013 - 12:11 PM

What I like to know is that the Denk II still loses the aperture for the other two magnification factor (not the reduction arm is used): I think it is 1.2X and 2.8X.



Remember, this problem is somewhat unique to telescopes with moving mirror focusing and baffles, though it could be encountered in some refractors if the in-focus allows the front of the focuser tube to cut into the light cone, which is a very real possibility in some cases.

To answer the question though, in the case of the MCT, I was loosing apeture in reduced mode (severe aperture loss) and staight through mode (minor loss).

This has to do with the fact that the Super-system I used was based on the use of a 2" diagonal.

The C14 and C8 both start to loose aperture once the back focus goes past about 200mm. The C9.25 I think starts loosing aperture once the back focus goes above about 170mm and the falloff is quick.

As an example, in my C5, as measured directly, I am using a back focus of 203mm, and the 127mm scope is being reduced to 122mm.


The Denkmeier System I used was based on a 2" diagonal, and the entire back focus required to use it was about 230mm or so.

With 230mm of back focus, the C14 is working at slighly less than 14" of apeture (Maybe 13.75") and the C8 would be working at about7.7". The plot that I have for the C9 suggests that the 230mm of back focus would give an aperture of 8.75".

Because the aperture is reduced, the central obstruction becomes bigger by percentage of aperture so the contrast is further lowered.

This is in straight through mode.

With the High Power arm in, the back focus requirment is reduced. I don't know how much it changes, but this would mean that the high power arm will give the system more apeture than straight though, because the mirror needs to be moved back slighly to re-position the focal plane.

Now I can only be fair about this and say that many people (perhaps most people) will not care about this very slight loss in performance.

So, it only matter if it matters, but for those that want to get the absolute best performance from their SCT or refractor, they want to make sure that they are not working with a reduced aperture.

If the new Denkmeier can be attached to a Baader Prism or other device that will shorten the light path, aperture loss can be reduced or prevented in SCTs, MCTs, and many refractors that were not designed to allow a full apeture when the focuser was fully racked in (and this is not at all unusual, though after the Stellarvue debacle 10 years ago, I think it doesn't happen so much anymore).

Again, the back focus is the issue, and the point where aperture loss is very model specific (The C11 has the loosest baffle of the Celstron SCTs).

But if the back focus is over 200mm, most SCTs will start loosing aperture, which means in straight through or reducer mode, many will work at reduced aperture. With the high power arm in, the amount of apeture reduction will either be reduced, or in some cases, perhaps even eliminated.

The key to doing this in these scopes is the Baader approach where the binoviewer attaches directly to the top of the diagonal and keeping the connection to the telescope as short as possible.

If someone wanted to use the new Denkmeier in an SCT and keep the system working at full apeture, they would need to go to a Baader type diagonal with a short connector (Like the Baader SCT connector which only adds 15mm of back focus) and the Prism, which only adds I think 38mm of back focus. The Mark V binos add about 120mm of back focus, so this system will have a total requirement of about 173mm.

But in my Denkmeier, the power-switch alone added 18mm of back focus, so right there, if you go with a standard 2" SCT adapter and a standard lenght 2" nose, even if you used a Baader type diagonal, you are well over 200mm, which is the point that many SCT models will start to loose aperture.

Here are the numbers....

The Baader SCT adapter requires 15mm of back focus.

The Baader Prism requires about 38mm of back focus.

the Power Switch requires about 18mm of back focus (unless they have made it thinner).

A large prism bino will require about 120mm of back focus (this is what the Mark v requries).

Add this up and you get 191mm. If someone wants to use a powerswitch and avoid aperture loss with a moving mirror scope even in straight though mode, this will be the best configuration to use.

A 2" diagonal alone will put you well over 200mm, even if it is the Baader 2" diagonal.

#18 faackanders2

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Posted 01 January 2013 - 02:27 PM

I am not a fan of the power-switch type units,

What don't you like about them? I'm trying to wade thru the info needed to buy some binoviewers.


Power switches are the best part of Denkmeier binoviewers. I loved the first one so much I got the reducer/multiplier one as well and bothe powerswitches stay perminently mounted on (with the reducer side being used as my finder mode). Next couple this with the 48m OCS (45mm clear aperture 1.2x Multiplier or 38mm clear aperture 1.4x Newtonian and 1.8x? Multiplier OCSs) and this gives me 3x3x3=27 power options per pair of eyepieces. I have two eyepieces pairs 24mm 68 AFOV and 14mm 82AFOV so this technically gives me 27x2=54 total power options, although the 14mm and Multiplier OCS combination is not that usefull - just too much power with my 17.5" f4.1 dob.

In summary, "Powerswitches Rule!", and are so much quicker and cheaper than buying multiple pairs of eyepieces.

Now I don't have the Denk filterswitch, but have the 2" Astrocrum filter slide instead, and this enables me to swap filters quickly even with Denk 2" OCS intrusion (except for the very lowest o.89x? power intrusion), but I still love the Astrocrumb filter slide also.

#19 faackanders2

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Posted 01 January 2013 - 02:32 PM

Intriguing, indeed! I really like the new user collimation system; about time! I've long advocated for the inclusion of no-tools collimation in all binocular equipment, as I've been doing for my own home-made gear since '96.

Clearly, at least one manufacturer out there has been paying attention to forums like this, where the incessant bleating of the herd about merging issues can't be missed.


Glen, I really didn't understand the "self-colimating" featuture, especially when indoors. I'd be affraid to make colimation worse, and proably ony use it if I couldn't merge (i.e last resort, like cleaning eyepieces).

#20 johnnyha

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Posted 01 January 2013 - 02:59 PM

The PowerXSwitch reduces the clear aperture of the Denk IIs by at least a mm if not a little more, in addition to introducing extra glass and extra weight. It requires a huge amount of re-focusing for different powers. It requires extra backfocus. It can vignette the view and reduce the aperture of the scope. But what really made me stop using mine forever was when I had to send it in for repairs - I just really, really enjoyed using the binoviewers without those big handles sticking out, or constantly messing with them.

When the PowerXSwitch came back from repair I sold it. :grin:

All that being said, it works well at what it does, is built solidly, and has given me some of my best views of Saturn in my 15" dob.

#21 Eddgie

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Posted 01 January 2013 - 03:24 PM

I think that in a Newtonian, the benefits of the Powerswitch are far greater.

In an SCT, it entials a lot of compromise though, and since my primary scope is an SCT, the powerswitch simply did not work to my satisfaction.

But for a Newtonian, I am sure it is everything everyone says it is.

Also, I did not like it at all on my 6" APO. It put me into a high power box. With the reducer arm in, the view was so dim that it seemed like I was looking trough an 80mm refactor.

Also, to get the "Advertised" 1.3x from the Denk Supersystem in a refractor, you have to use the Denkmeier diagonal (or some other diagonal that has the same threads). Otherwise, the OCS yeilds about 1.4x rather than 1.3x. Denkmeier doesn't clearly say this on their web page, but in the User's Guide it explains that the benefit of the Denkmeier Diagonal is that it lowers the magnification factor from 1.4x to 1.3x.

Frankly, I didn't like finding that out. I felt kind of deceived by the web page.

Anyway, I did not find it to be all that useful in my 6" APO because I don't use that scope for planets, so the high power arm was of no particular benefit to me in that scope.

Again, I think in a Newt or a refactor that will reach focus without the OCS, this would be a great way to go!

#22 faackanders2

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Posted 01 January 2013 - 03:53 PM

Newtonian reflectors definitely require OCS's to focus (believe the same is true for refractors as well).

Also believe star sweeper OCS can only be used by SCTs.

#23 Eddgie

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Posted 01 January 2013 - 04:01 PM

I did run a light protection test on my c8 with the power switch and the reducer reduced effective aperture to a hair over 6 inches. Straight through I was measuring around 7-3/8 effective aperture, the mag mode showed almost no aperture reduction. Just my results and in no way difinative other than that it did substantiate the effect of the power switch in the reduction of aperture. In addition...with the reduction of aperture with the CO being a constant, the CO percentage increases as well. Hope this helps.


Thanks for sharing this data.

Can you tell me what your configuration was, or do you happen to know the back focus for the entire system? I am collecting this info for reference to use when this topic comes up again.

I personally an not at all surprised by the numbers. I know that the first time I used the low power arm in my C14, something was seriously wrong. The view was nothing short of horrible! I remember thinking that it looked like I was looking though a C10!!! I did not do a measurment, but I estimate that the aperture was less than 11"!

Straight though, It was about 13.3". This does not sound like much, but I could see the difference (and this is about a 12% difference in image brightness so anyone should be able to see this. Eyepiece forum guys can see a 4% difference.. LOL).

Also, you might be interested to know that using the Baader diagonal and the Glee Telescopressor, AstroJensen was able to get his C8 to work with only 10mm aperture loss. This is about as good as it gets with an SCT and a reducer. I am not aware of another configuration that comes close to this. But he was also using the Maxbright Binoviewer, and while this unit has smaller prisms, it also has 10mm less light path than the Mark Vs and even the standard Denk. I suspect that the new Binotron will have at least as much as the mark V, and maybe more.

I do not know if he used the Baader SCT to T2 converter in his light path or not, but if he didn't this might improve the situation a bit. But again, he was using the Maxbrigth/T2 which is the shortest light path in the bino world that I know of.

But thanks for confirming this message. I don't want people to think I make this stuff up.. LOL.

Bottom line is that a focal reducer (low power arm) and binoviewer used with just about any SCT made will entail a pretty serious aperture reduction, and 2" based systems will often not work at full aperture on many SCTs even in straight through mode.

This is why I went to the Mark V/T2 Prism. It gives the shortest possible back focus in a large prism bino when used in an SCT.

And while some SCTs may still loose a bit of apeture, this will give them the largest possible aperture in a big prism bino. You only trade a couple of millimaters of aperture but this is compensated for by being able to use a 24mm Pan or similar so you can get reasonably larger true field.

#24 Eddgie

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Posted 01 January 2013 - 04:43 PM

By the way.. No one should think that I am slamming the Binotron in any way. I think it is an exciting new product! Just want to make sure that the powerswitch issue was clearly and cleanly addressed. This is just an SCT issue, but an important one if you own an SCT.

And this.. If Denkmeier is smart, they will introduce a very short back focus solution, or list a dovetail adapter that would allow the use of the Baader prism on their web page.

Just going to the T2 prism can save anywhere from 15mm to 50mm of back focus.

And no one should use a 2" diagonal on a binoviewer in an SCT. Not only does it usually reduce the aperture, but it also makes a big increase in focal lenght, which raises magnificaiton and reduces field size.

This is what made the Mark V so attractive to me, and unless Denkmeier can counter, people that have done their homework may still move to the Mark V because of the shorter light path.

Home run for Newt onwers though. Beautiful unit. I am impressed.

#25 bcuddihee

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Posted 01 January 2013 - 05:04 PM

I don't know the back focus numbers but I am using a William Optics 2" diagonal with a WO SCT threaded adapter to couple it to the visual back (no nose piece). The power switch is attached directly to the top of the diagonal(the S2 config),with binos with 2" adapter sitting on top. actually I got some heat on one of the threads for making a point of the aperture reduction issue, as if I was trying to put down SCT's or something. Nothing could be further from the case. The C8 I own is one of the best examples I've seen and I wouldn't part with it for a even 6"AP...........well maybe:)
bc






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