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Equipment Discussions >> Binoviewers

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johnnyha
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Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: DENK "BINOTRON" - FIRST LIGHT new [Re: GlennLeDrew]
      #5678954 - 02/14/13 08:35 AM

I think he might be speaking SCT language...? It's all foreign to me.

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Mike Harvey
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Reged: 03/01/04

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Re: DENK "BINOTRON" - FIRST LIGHT new [Re: GlennLeDrew]
      #5679752 - 02/14/13 03:31 PM

Quote:

The sheer size of the 45s resulting in a light path so long that the 20s might be performing as 12s...

What on Earth does does this mean?




An assumption that, by virtue of the sheer physical size of this particular binoviewer, it work work like an extension tube...longer light path - higher amplification factor.
Without a reducer, even the TeleVue Binoview acted like a 3X Barlow.
I haven't heard that the Siebert uses a focal reducer (or OCS) to overcome this (TeleVue didn't). What am I missing?


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Bob S.
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Re: DENK "BINOTRON" - FIRST LIGHT new [Re: Mike Harvey]
      #5679787 - 02/14/13 03:54 PM

Quote:

Quote:

The sheer size of the 45s resulting in a light path so long that the 20s might be performing as 12s...

What on Earth does does this mean?




An assumption that, by virtue of the sheer physical size of this particular binoviewer, it work work like an extension tube...longer light path - higher amplification factor.
Without a reducer, even the TeleVue Binoview acted like a 3X Barlow.
I haven't heard that the Siebert uses a focal reducer (or OCS) to overcome this (TeleVue didn't). What am I missing?




Mike, You would be right if Harry Siebert hadn't designed a special set of OCA modules for this Siebert 45. The range of the OCA is 1.3x-2.7x. Bob

Edited by Bob S. (02/14/13 03:58 PM)


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Jeff B
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Re: DENK "BINOTRON" - FIRST LIGHT new [Re: Mike Harvey]
      #5679865 - 02/14/13 04:43 PM

Spoke to Russ and I'm on the list. I can't wait.

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junomike
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Re: DENK "BINOTRON" - FIRST LIGHT [Re: GlennLeDrew]
      #5679888 - 02/14/13 04:59 PM

Glenn, I believe this refers to how Binoviewers increase the Focal Length In an SCT and thus the overall magnification.
So in an SCT, because of the extra Optical Path of the 2" Binoviewer, 20mm eyepieces would yield the same magnification as 12mm would in Mono mode.
Not saying this is correct, but that's what I think was Implied.

Mike


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faackanders2
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Reged: 03/28/11

Re: DENK "BINOTRON" - FIRST LIGHT new [Re: junomike]
      #5685556 - 02/17/13 05:13 PM

I believe that is correct. OCSs usually act like barlows multiplying power to be able to focus.

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johnnyha
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Reged: 11/12/06

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Re: DENK "BINOTRON" - FIRST LIGHT new [Re: faackanders2]
      #5693159 - 02/21/13 05:13 PM

Russ he has just posted Zygo tests and beam splitter transmission data on his website, these Bino27 prisms are truly outstanding.

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Eddgie
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Re: DENK "BINOTRON" - FIRST LIGHT new [Re: junomike]
      #5693452 - 02/21/13 08:06 PM

It can be complicated in refractors.

The Maxbrights with a T2 required a 1.5x GPC to reach focus in my 6" APO.

But when I went to the Mark Vs (same prism), I could no longer reach focus with the 1.5x configuration, and I am not even sure that the 1.7x would work because these seem to be actually only 1.6x, and I only had about 2mm of in-focus left when using the Maxbrights.

If I went to a 2x configuration to be sure of reaching focus, I would increase my magnification 75%.

Some of this would be offset because I could use a bigger eyepiece in the Mark Vs.

If I went to a giant bino with a light path that was another 20mm or so, I might need even more magnification to reach focus.

In the SCT, it is not as bad, but past 200mm, and the C14 looses aperture.

So, If I went to a 2" diagonal to support a giant prism bino, I would have to add so much back focus that the system would loose a lot of aperture.

In fact, even with the standard Denkmeier Supersystem used with a 2" diagonal, the scope was already only working at 13.2" of aperture.

With my current configuration (Baader Clicklock, Baader T2 Standard prism, and Mark Vs, (total back focus of about 198 mm of back focus).

This gives a focal length of about 4000mm, but full aperture (My scope starts to cut off the light cone right at 200mm).

A big bino though, using a 2" diagonal but with a light path of 140mm, would have a total of perhaps 270mm of back focus (maybe more).

In this case, the C14 would be working at about 4300mm focal length, but the aperture would be reduced to about 13 inches or less.

You can overdo it on the prism size for refractors or SCTs. The bigger the prism, the more Barlow or back focus you need, and in the SCTs, you would almost for sure loose aperture (except C11).

I did some quick calculations, and in almost every case for refractors, if the change from a Maxbright size bino to a Mark V required a step up in GPC, the advantage of the bigger prism would be almost completely negated.

In other words, you could get the same size true field from the Maxbrights using a 20mm Explore Scientific as you could get from a Mark V using 24mm Panoptics if the Mark Vs required one step up in GPC strength.

And if you had a 2" with a big enough prism to use a big 2" eyepiece like a 27mm Pan, you might need even more GPC, so that in the end, you might wind up with no bigger true field than the Maxbrights.

Light path is the the great evil of binovierwers. Unless one is willing to modify a telecope that cannot reach focus without a GPC or OCS, it is very difficult to get a wider field by going to a bigger aperture bino for refractors, and many SCTs will experience aperture loss when giant prisms are used, unless they use an OCS of course, but then what would be the point of the bigger prisms?

I went to the Mark Vs for the C14 because the increase in field size in this case was enough to justify it, but I wrote off the notion of using them in the 6" APO.

Think about it this way..... If I had to use 2x in the 6" APO to reach focus, that would give me 2430mm of focal length.

Heck, I can use them on my EdgeHD 8" and get 2350mm with a brighter field that is every bit as sharp? What would be the point?

I simply abandoned the idea of using the binoviewers with the 6" APO when I realized I could get a bigger, brighter true field out of the EdgeHD 8". It did not make any sense at all to pursue getting the Mark Vs to work on the 6" APO.


Edited by Eddgie (02/21/13 08:08 PM)


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mhilscher
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Reged: 07/13/11

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Re: DENK "BINOTRON" - FIRST LIGHT new [Re: Eddgie]
      #5693481 - 02/21/13 08:18 PM

well explained

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johnnyha
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Re: DENK "BINOTRON" - FIRST LIGHT new [Re: mhilscher]
      #5693639 - 02/21/13 10:00 PM

It's very well explained but also completely due to the longer tube on Eddgie's scope. I'm actually considering keeping my MkVs when the B27's arrive just for the spectacular view they render in my 6" APO at 1X with Pan 24s or Brandon 32s.

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Fred1
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Re: DENK "BINOTRON" - FIRST LIGHT new [Re: johnnyha]
      #5693849 - 02/22/13 12:29 AM

Quote:

It's very well explained but also completely due to the longer tube on Eddgie's scope. I'm actually considering keeping my MkVs when the B27's arrive just for the spectacular view they render in my 6" APO at 1X with Pan 24s or Brandon 32s.




Keep 'em both. There are times when I am sooooo glad I have two sets of binos.


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faackanders2
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Reged: 03/28/11

Re: DENK "BINOTRON" - FIRST LIGHT new [Re: GlennLeDrew]
      #5709883 - 03/03/13 02:37 AM

Quote:

The sheer size of the 45s resulting in a light path so long that the 20s might be performing as 12s...

What on Earth does does this mean?




The Multipurpose OCS may require an extension or more infocus than the Newtonian OCS (it does when I am at lowest LL power mode of dual power switches). If you require an extension it would change the focal length of the system. If it is just infocus (without an extension) I don't know what he is talking about either?

I knew exactly what all the powers were with just one power switch. Adding the second one (reducer/multiplier) increased the length and changed all the powers a little.
I only know the LL and HH for sure provided by Russ, and had to estimate multiplying the powers of both power switches in series.

I guess we could do the drift time measurement to know for sure.


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Jeff B
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Re: DENK "BINOTRON" - FIRST LIGHT new [Re: Fred1]
      #5710227 - 03/03/13 09:47 AM






Keep 'em both. There are times when I am sooooo glad I have two sets of binos.




Amen!


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Eddgie
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Re: DENK "BINOTRON" - FIRST LIGHT new [Re: Mr. Bill]
      #5710337 - 03/03/13 10:44 AM

Quote:

With my IPD (67mm) I only use 1 1/4 eps....the largest fieldstop for 1 1/4 is 27mm (24mm Pans) so 30mm and more is not needed


.

The Baader Hyperions have a 28mm field stop.

When measured with a caliper, I got 28mm.

The Televue 40mm Plossls were 27mm.

Is 1 millimeter a big deal?

Well, yes and no I suppose. On one hand, I very much like to see a very sharp field stop in my eyepieces with zero softness. For many this is not important at all and while it is cosmetic, it is what I personally like. The 24mm Hyperions have a very sharp field stop.

And as for the difference, well a 3% wider field in a binoviewer is a 3% wider field in a binoviewer.

And if you are using a C14, it all adds up.

I have no investment in what other people buy. Only trying to say that there are bigger field stops in 1.25" eyepeices.

Does it matter to you or to anyone else? Maybe not.

Juat a fact so I though I would introduce it.


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swampdog
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Reged: 10/18/12

Loc: Minnesota
Re: DENK "BINOTRON" - FIRST LIGHT new [Re: Eddgie]
      #5752715 - 03/23/13 09:04 PM

I'm looking for more 1st. light reports! Subsequent "nights out" from actual owners also! I appreciate everyones contribution, sure looks like a nice product. Thanks for sharing your experience.

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Mauikj
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Reged: 06/08/08

Loc: Maui, Hawaii, USA
Re: DENK "BINOTRON" - FIRST LIGHT new [Re: swampdog]
      #5754812 - 03/24/13 07:34 PM

Hey Swampdog,

Had my Binotrons with Denk 21's out a fews days back hooked up to my Tak TOA 130. The conditions were much better than my first night out and WOW did they perform. The moon was amazing. The Tak by itself is great on the moon but with the binoviewers the view was breathtaking. Razor sharp and beautiful subtle coloring of the lunar surface. Jupiter was also a wealth of detail and the moons perfect tiny disks. What is really amazing to me (and I know most binoviewer users already know this but it is new to me) is how relaxing it is to view with two eyes instead of one. I can't wait to bring them to a really dark site and put them in my Dob. This night was in my yard which is kind of dark -(I don't know the darkness scales but I can see the milky way from my yard but not distinct light and dark areas within it - it is just a hazy band of light.). The binos really performed beyond my expectations.


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George N
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Reged: 05/19/06

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Re: DENK "BINOTRON" - FIRST LIGHT new [Re: Mauikj]
      #5754981 - 03/24/13 09:11 PM

When upgrading from the Denk II, can't one keep the old PowerX switch? I also have the Newt reducer lens..... Would I keep that?

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swampdog
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Reged: 10/18/12

Loc: Minnesota
Re: DENK "BINOTRON" - FIRST LIGHT new [Re: Mauikj]
      #5755109 - 03/24/13 10:21 PM

Right on..and Aloha! Nice report, nothing like a good, comfortable pair of binocs for viewing. My experience is daytime scenic/hunting scenarios, like most people I suppose, and the higher end glass, if you're fortunate enough to own, really is a pleasure to use. And that's what I was hoping, in considering these binotrons. You know, I'm 50 yrs. old & started this astronomy hobby 2 yrs. past, I like the fact when using a scope, you bow your head when you look to the sky, and sometimes just look up, take it all in. I didn't know much of these astronomy things were even availiable to most people...so thanks again.

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johnnyha
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Reged: 11/12/06

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Re: DENK "BINOTRON" - FIRST LIGHT new [Re: swampdog]
      #5760921 - 03/27/13 05:50 PM

Mine shipped today!

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Aquarist
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Reged: 08/27/12

Loc: Illinois
Re: DENK "BINOTRON" - FIRST LIGHT new [Re: johnnyha]
      #5761087 - 03/27/13 07:16 PM

Well Johnny, we will be waiting for a report!

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