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Equipment Discussions >> Binoviewers

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MikeBOKC
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Denk Binotron rollout
      #5597565 - 12/31/12 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://deepskybinoviewer.com/index.cfm?fuseaction=category.display&catego...


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Jim7728
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Re: Denk Binotron rollout new [Re: MikeBOKC]
      #5597646 - 12/31/12 10:09 AM

Dang! Why was I not informed of this sooner?

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


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Eddgie
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Re: Denk Binotron rollout new [Re: MikeBOKC]
      #5597712 - 12/31/12 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.


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mich_al
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Re: Denk Binotron rollout new [Re: Eddgie]
      #5598052 - 12/31/12 02:03 PM

Quote:

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.


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Eddgie
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Re: Denk Binotron rollout new [Re: mich_al]
      #5598104 - 12/31/12 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?


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Denimsky
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Re: Denk Binotron rollout new [Re: Eddgie]
      #5598132 - 12/31/12 03:00 PM

Quote:

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.


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Denimsky
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Reged: 01/21/07

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Re: Denk Binotron rollout new [Re: Denimsky]
      #5598140 - 12/31/12 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

Edited by Denimsky (12/31/12 03:05 PM)


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johnnyha
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Re: Denk Binotron rollout new [Re: Denimsky]
      #5598300 - 12/31/12 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.

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DaveJ
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Re: Denk Binotron rollout new [Re: johnnyha]
      #5598337 - 12/31/12 04:47 PM

Quote:

...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.


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Eddgie
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Re: Denk Binotron rollout new [Re: Denimsky]
      #5598350 - 12/31/12 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.


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Denimsky
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Reged: 01/21/07

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Re: Denk Binotron rollout new [Re: Eddgie]
      #5598375 - 12/31/12 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.

Edited by Denimsky (12/31/12 05:12 PM)


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johntrob
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Re: Denk Binotron rollout new [Re: Denimsky]
      #5598438 - 12/31/12 05:39 PM

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

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GlennLeDrew
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Re: Denk Binotron rollout new [Re: johntrob]
      #5598480 - 12/31/12 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.


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mich_al
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Re: Denk Binotron rollout new [Re: GlennLeDrew]
      #5598657 - 12/31/12 07:58 PM

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


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bcuddihee
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Re: Denk Binotron rollout new [Re: mich_al]
      #5598767 - 12/31/12 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.

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Paul G
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Re: Denk Binotron rollout new [Re: Eddgie]
      #5599268 - 01/01/13 09:42 AM

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

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Eddgie
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Re: Denk Binotron rollout new [Re: Denimsky]
      #5599470 - 01/01/13 12:11 PM

Quote:

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.


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faackanders2
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Re: Denk Binotron rollout new [Re: mich_al]
      #5599729 - 01/01/13 02:27 PM

Quote:

Quote:

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.


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faackanders2
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Re: Denk Binotron rollout new [Re: GlennLeDrew]
      #5599738 - 01/01/13 02:32 PM

Quote:

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).


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johnnyha
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Re: Denk Binotron rollout [Re: faackanders2]
      #5599779 - 01/01/13 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.

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.


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