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Baader Mark V vs Denkmeier Binotron binoviewer ?

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#1 vkhastro1

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Posted 02 May 2013 - 11:59 AM

Has anyone done a direct "shootout" between the Baader Mark V and the Denkmeier Binotron? Which is the preferred option based on ergonomics,
optical quality, smallest back focus (especially for SCT),etc ? I presently use the Baader Maxbrights and Baader Zeiss T2 prism setup for the minimal back focus in the SCT mode. I also have the Denkmeier II supersystem binoviewer with powerswitch/filter slider setup for use with refractor, reflector and SCT.

#2 denis0007dl

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Posted 02 May 2013 - 12:29 PM

johnnyha have them both, so we expect soon shootout :)

#3 johnnyha

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Posted 02 May 2013 - 01:36 PM

Well the Mark V clearly requires the least amount of backfocus. I have not had a chance to compare them head to head due to weather, but they are both excellent. The Mk Vs are of course known for their quality but I have been extremely happy with the B27's optical quality after just two outings. I also prefer the B27's ergonomically due to their easily adjusted diopters, I can incrementally shift the focus on either eyepiece "on the fly" while viewing with both eyes. This feature alone is so fantastic that it makes it difficult for me to even reach for the MkV's again. ;) I also love the collimation feature of the B27's and their lighter weight.

#4 Ryuno

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Posted 04 September 2013 - 07:48 PM

Hello Johnny
Are their any updates about your comparison of the binoviewers?
I am shopping for one and deciding between a Denkmeier, a Baader and a Vernonscope.

The Vernonscope is the cheapest of the three. Do you happen to know this bino or know someone who knows it?

Best regards from Tokyo
Heinz

#5 REC

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Posted 05 September 2013 - 08:09 AM

Where id Eddgie??

#6 Eddgie

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Posted 05 September 2013 - 08:31 AM

I have used both.

They are very different units with very different strengths.

Optically though, I find little difference. Both are optically superb.

The differences are basically mechanical differences. The Binotron without the powerswitch is lighter, but with the powerswitch is heavier.

The Binotron has excellent diopter function. Easier to access than the very thin ring on the Mark V, but the very low profile of the Mark V allows for a much shorter light path.

The diopter ring adjustment ring on the Binotron is recessed and I found it a little harder to get at even without gloves on. It is much easier to change eyepeices on the Mark V, but if you have the Supersystem you most likey do far less eyepiece changing, yes? So, one is easier to change eyepeices, the other greatly reduces eyepeice changes.

The Mark V is king of the hill for clear apeture. Even 28mm feild stop eyepeices are bright and crisp right to the edge.

The Mark V has a really excellent collimatino adjustment, but the Mark V I have has perfect collimation.. This could be a neutral, but for someone that has had trouble with merging, the Binotron would fix that problem.

And of course the Binotron can have a powerswitch.

A la carte, I personally still prefer the Mark V, but the powerswitch is an important factor, and I can easily seeing that beeing the over-riding factor in many purchases.

Optically though, I find the performance to be pretty much identical.

I want a Binotron, but at the same time, I don't see myself selling the Mark V. I actually prefer it for my EdgeHD 8". Due to apeture loss caused by the long light path, I found the Binotron not well suited to that scope, and in the Newt, I don't see a huge advantage to the Binotron other than the powerswitch.

Both are first class binoviewers, so it is more the mechanical features, powerswitch, and clear apeture that seprate them.

#7 REC

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Posted 05 September 2013 - 09:58 AM

Ed, just a quick question on my Denk2 PS...can the power switch be removed easily if I just want to use the BV alone and save some weight and light path? Does it just unscrew...seems to be on there pretty tight?

Thanks,

Bob

#8 Levine

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Posted 05 September 2013 - 10:16 AM

Eddgie, Thomas, and others:

Consider the following:

-Cost is off the table as a determining factor
-Flexibility, reliability, ease of use, and service after the sale are the primary concerns
-You are restricted to only ONE binoviewer:

Would you choose the Mark V or the Binotron?

...Or would you consider a 2" system (Siebert)?

...Or none of the above?!

Why?

:question:

#9 TG

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Posted 05 September 2013 - 11:08 AM

I have no experience of the Binotron but here's what I love about the Mark V:

- Optically perfect. Star testing my AP178 with the binoviewer, I find no difference from star testing it without. Shine a laser into the "nose" of the Mark V and two identical beams come out the eyepiece ends. Project them on a far wall and you can see how well it's collimated. It's no surprise that this is the only BV that AP recommends and sells.

- Perfect color balance. BVs typically have different hues for the two sides. The Mark V is perfectly balanced. It's easy to verify: put a white paper over your scope and illuminate evenly and take images from either eyepiece and compare the histograms; they come out identical.

- Solid Zeiss quality, Zeiss coatings. What more is there to say.

- Click-lock. Love this feature.

- 28mm clear aperture.

Here's what I don't like about it:

- Attaching to the diagonal can be fraught with peril as the many tales of Mark V's hitting concrete in this group attest.

- Sucks up a good deal of back-focus. I had to shorten the tube on my AP. With a mirror diagonal, I had observable spherical aberration in my C11HD till I went with the Maxbright prism diagonal.

- OCAs are all telenegative amplifiers. There is no zero power OCA available like the one from Siebert.

- Price. You could buy a 4" TV refractor on Amart for its price. But in the end I think the quality is worth the price, and it keeps it value very well.

- Minor nit: the opening/closing action to adjust the pupillary distance is fairly stiff. While it may be a feature, I much preferred the smooth action on Siebert's Black Knight BVs, the only other ones I've owned.

Sorry, I don't have a direct comparison with Binotron but I hope the above helps.

Tanveer.

#10 Levine

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Posted 05 September 2013 - 12:21 PM

Tanveer,

Thanks for this!

"Crashing Bino Syndrome" as it pertains to the Mark V, may be traced back to some not fully tightening the setscrew on the Quick Release adapter. The screw would then loosen further, fall out, and provoke tears.

This from Edggie, on another thread in this Forum. I have no personal experience with the Mark V.

#11 Eddgie

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Posted 05 September 2013 - 12:55 PM

Yes, the power switch can be removed. It unscrews from the bino body. The nose can then be threaded directly into the bino body.

This cuts about 19mm or so from the light path.

There is a very thin ring at the top of the threaded part of the powerswitch that screws into the base of the BV. You will see this ring when you separate them.

This ring may move when you remove the powerswitch.

The symptom will be that when you re-install the powerswitch, it may not line up perfectly with the body of the bino. The little thin ring is a stop that allows you to adjust the final stopping place of the powerswitch so you can restore the correct alignment. If the power switch rotates to far or not far enough on re-install, you can remove the power switch and raise or lower this little ring as necessary to get the rotation of the switch perfect.

It most likely will not move when you remove the powerswitch, but if it does, it is very simple to get it back into proper position.

Anyway, it should unscrew. I would not get crazy with the force, but it may take some amount of pressure to get it off the first time.

#12 DaveJ

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Posted 05 September 2013 - 12:57 PM

"Crashing Bino Syndrome" as it pertains to the Mark V, may be traced back to some not fully tightening the setscrew on the Quick Release adapter. The screw would then loosen further, fall out, and provoke tears.


There's no maybe about it, that's the only thing it could possibly be. Keeping the large easy-to-see, easy-to-grab screw tightened with a gentle twist is all that's required. I've never come close to dropping my Mark Vs. Someone mentioned it being too short. I lengthened mine with an inch of hard rubber fuel hose purchased for a few cents from an auto parts store.

#13 Levine

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Posted 05 September 2013 - 01:36 PM

"Crashing Bino Syndrome" as it pertains to the Mark V, may be traced back to some not fully tightening the setscrew on the Quick Release adapter. The screw would then loosen further, fall out, and provoke tears.


There's no maybe about it, that's the only thing it could possibly be. Keeping the large easy-to-see, easy-to-grab screw tightened with a gentle twist is all that's required. I've never come close to dropping my Mark Vs. Someone mentioned it being too short. I lengthened mine with an inch of hard rubber fuel hose purchased for a few cents from an auto parts store.


:ubetcha:

#14 REC

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Posted 05 September 2013 - 01:42 PM

Thanks Ed, do you think the 19mm saved would be worth removing the PS....maybe a little brighter.

I would like to do a final comparison between the WO I have and the Denk. Probably going to sell the WO.

Another thought is that my WO will work on my ED80 but not the Denk the way I have it now setup and would have to buy more "stuff".

Do you think using a BV in the 80ED is a good idea in the first place? I have to attach the 1.6x barlow in front of the diagonal to get it to focus.

#15 Eddgie

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Posted 05 September 2013 - 04:06 PM

Well, I think that it will be a much fairer test to compare the Denk to the WO with a bit more similar light path.

As for binoviewing the 80ED, I mean you can, but I don't know what the point would be. You are turning your wonderful wide field scope into a fairly narrow AFOV 70mm telescope (just figuring the dimming factor).

But that is me. I do use the Mark V on my C5, but this even seems dim to me.

I have thought about selling the C5 and replacing it with a C6, but it never seems to end, so for now, I am just hanging tight.

I did buy a cheap ($59) Celestron 4" Achromat and I am using it with binoviewers, though I had to cut the tube to do that. For $59, it was worth it....

But an 80mm scope is pretty small. I guess it just depends on you.

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#16 REC

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Posted 05 September 2013 - 05:41 PM

Good point on using the BV in the 80mm.

I bought that $59.00 close out as well....hella of a deal I could not pass up! I stuck it on my EQ2 that i have..looks like you have one like it as well. Pretty nice scope and I will compare it to my ETX-125 on Saturn tonight.

Clear Skies:)

#17 DaveJ

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Posted 05 September 2013 - 06:07 PM

Good point on using the BV in the 80mm...


I use binoviewers in my wife's 80mm triplet APO all the time and much prefer the view to mono-eyepiece mode. There's something magical about binoviewers regardless of aperture of the telescope. I've binoviewed through scopes from 80mm to 16" in aperture and have a hard time going back to mono now in any of them.

#18 Eddgie

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Posted 05 September 2013 - 06:33 PM

The Celestron did not reach focus with BVs. I had to cut 1.25" from the end of the tube.

Now it reaches focus with the Mark V/T2 Prism.

It actually works really well. I get about a 1.5 degree true field with 24mm ES68s, and about 1.55 degrees with the 35mm Ultimas. The Ultimas work great for faint targets but for general sweeping, I prefer the 24 ES expansive 68 degree field.

Still, the view seems dim to me. If my sky conditions were darker, I think I could get more into it, but from my city location, a 4" refractor just isn't much telescopes.

#19 johnnyha

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Posted 06 September 2013 - 01:38 AM

Hello Johnny
Are their any updates about your comparison of the binoviewers?

I haven't had a chance to use them lately so no real updates. I think Eddgie has covered the differences pretty well. I definitely prefer the B27 ergonomics altho I see essentially no difference optically. And I have nothing but good things to say about Russ's customer service at Denkmeier. As I have reported here before, turnaround for Denk repair was one week and for MkV it took 9 months so that is a pretty major difference and a very real consideration.

#20 Eddgie

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Posted 06 September 2013 - 08:50 AM

-Cost is off the table as a determining factor
-Flexibility, reliability, ease of use, and service after the sale are the primary concerns


Would you choose the Mark V or the Binotron?

...Or would you consider a 2" system (Siebert)?



Last one first.

I would not consider a 2" system. The back focus requirements are so onerous that I think you would find them to be impractical in most scopes.

The light path through this system is I believe over 150mm. By the time you add a 2" diagonal for an SCT, and a visual back, you are looking at a back focus of over 300mm. No SCT made will be better than barely within diffraction limit with this much back focus (spherical aberration will be near 1/4th wave).

No Newtonian or no refractor is going to reach focus without at least a 2x barlow and maybe more. This means that while you can use 2" eyepeices, you may still get a wider true field using 1.25" eyepecies in either the Denk or the Mark V. The big barlow requirement imposed by the big light path length does more to offset the big prism than the big prism buys you by allowing the use of a big eyepiece. Lets not even get into the weight issue.

And before I answer further, let me be clear that off axis performance is extremely important to me. This means that I want a field that is completely free of vignetting, and that is not loosing off axis rays from the light cone so that the illumination is falling off (these are two different things). I value these things perhaps far more than most people.

With that said, if you made me pick, I would pick the Mark V.

The details of the answer would bore the life out of any reader out there, but in the end, I believe that for my particular mix of scopes, the Mark Vs would give me the best overall result.

If the only scope I had was a medium focal ratio Newt or Dob, the answer might be different.

But I have a variety of scopes, and I get the best balance of function in all of the scopes with the Mark V.

That is me though, and you asked me for my own answer. I am sure that others will differ.

One use of any powerswitching system made in the EdgeHD 8" though would tell you immediately that it is not a good match. You cannot use this kind of system in this particular scope without serious performance compromises.

If the only scope I was going to use was the 12" f/4.9 dob, It would be a more difficult decision.

The 24mm ES 68s don't give quite the same low power, but the much larger field stop than the D21s makes the true field surprisingly close.

The 1.7 GPC is a true coma correcting design and even inexpensive eyepeices like 24mm Hyperion seem to give very sharp off axis performance.

My biggest concern about the powerswitching systems though is that in the low power arm, the field illumination is very uneven, being much brighter at the center and falling off evenly from there. The illumination of the Mark V with 1.7x GPC seems much more even to me though to be fair, this is over a slightly narrower true field (though if you do the math, you realize that the field is not that much smaller).

On the other hand, using a powerswtich type system, many observers could go all night without having to change eyepecies, and there is a lot to be said for that.

So, if cost is no object, I would say to own them both.

But if you really made me have to choose, then with my own mix of scopes and my own preference for a fully unvignetted and well illuminated field, it would be the Mark Vs. The EdgeHD was completely unsatisfying to use with the Binotron, even with a T2 Prism diagonal. In low power, I might as well have been using a C6 with a Maxbright/T2 prism. In the EdgeHD, the Mark V with a pair of 35mm Ultimas gave a far better result than the low power arm of the powerswtich did. There is simply far to much aperture loss when you use any kind of reducer system with the EdgeHD 8" and back focus over about 110mm.

I think that one of the other forum members (REC) may also be seeing aggressive aperture reduction in another SCT (f/8 I think).

Anyway, my own requiremts for no vignetting and an even field illumination would make me choose the Mark V.

I like the Binotrons and intend to buy a pair, but they just are not a good choice for my other scopes. In the Newt though, I think that even with the field illumination dropoff, I will still use them.

But the question was absolute, and my answer is absolute as well. If you made me pick one of the other, it would be the Mark V.

#21 REC

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Posted 06 September 2013 - 09:21 AM

Ed, yes my scope I'm using the Denks in is a 8" SCT f/10. But, just wondering about your issue withe the Edge HD. My scope is an ACF model which is different from a traditional SCT and has a flat field and no coma at the edge.

Does the use of a different secondary in an ACF have any effect in when using the BV?

Bob

#22 Eddgie

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Posted 06 September 2013 - 10:21 AM

The issue with the EdgeHD 8" is severe aperture loss.

Even the Mark Vs only work at about 7.8" of aperture, and this is with the 10mm SCT to T2 connector (10mm of light path) T2 Prism (38mm of light path) and Mark V (123mm of light path). This is a total light path of about 171mm, and even with this short a path, I am loosing .2" of aperture.

The Binotron has about 127mm of light path with the diopters fully racked in, and if I mate it to the T2 Prism, I add about another 8mm to that for the Quick Connector. The Powerswitch adds 19mm, and we still have 38mm for the diagonal and 10mm for the connector. Total light path is 202mm. That reduces the EdgeHD 8" from 8" of aperture to less than 7.5" of aperture, and that is only in the "both arms out" position.

If you kick in the reducer, the aperture falls to less than 7". The field is wider, sure, but at the expense of a lot of brightness loss.

Remember, as the aperture gets smaller, the secondary shading as a percentage of aperture gets larger.

For a 7" aperture, you only have 38 inch of light collection and you loose 5 square inches because of the obstruction, so now you are at 33 square inches.

By the time you factor in transmission loss, you are looking at a pretty dim image.

Also, in arms out mode with the Binotron, not only is the aperture less than 7.5", but the system the focal length of the scope is 90mm longer than with the Mark V.

If you start with 2300mm of focal length (which is about what you have with the Binotron in the EdgeHD) and you take .63 of that, you are working at 1449mm. This mean D21s give you 68x.

If you use the Mark V with 35mm Ultimas, you get about 63x, and the bigger field stop of the Ultimas means that the field is wider than with the D21s. You are using a bigger field stop at a lower magnifications. The Apparent field is of course bigger in the D21s, but the true field and exit pupil is bigger in the 35s, which helps offset some of the binoviewer imposed dimming.

And you could use 35mms in the Denks, but they vignette notcibly in the low power arm, and as I mentioned previously, I do not like to see any vignetting. In the EdgeHD, the 35mm Ultimas are bright and sharpt to the edge. The same eyepecies in the Denks vignette.

And remember, this is comparing a 7.8" aperture to a 6.9" aperture. Which one do you think gives a brighter image..

I did not like the Binotron in the EdgeHD 8". It is not a good match for the scope.

Even with the Mark V, I am not working at full aperture, but it is close enough to make it difficult to see the difference in brightness.

And remember, I am using the shortest possible light path possible for the Binotron. There is no way to get it as short as the Mark V even If you remove the power switch arm, and if you do, you still have the smaller prisms in the Denks so the outside of the field is not as well illuminated as with the Binotrons using 24mm Hyhperions or 35mm Ultimas.

Again, this is me. I am very sensitive to field illumination..

What works for others is much different than what works for me, and I did not like the result in the EdgeHD 8".

#23 Scott99

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Posted 06 September 2013 - 12:04 PM

The little screw on the Baader is somewhat annoying but I've never been close to dropping it either, even with frozen fingers.

I enjoyed using a friends 2-inch BV but I wouldn't want one. I don't really like the way BV"s dim the view of DSO's, so I don't do much low power, wide-field binoviewing. Mostly I use it for planetary, or a quick look around at low power with 25mm Plossl eyepieces.

For higher power the 2 inch system is overkill. I spent the money getting better transmission and clarity with the Mark V.

#24 Pingster

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Posted 06 September 2013 - 04:55 PM

Eddgie, thats a very informative reply, I have been thinking very hard about the binotron. And the points you raised mirror what I fear.

I love my mrk5s perfect fov in 24pans. Denki, I dislike the way in lower power arm you get vignetting plus you can see uneven brightness around one edge of the fov... caused by the power switch lens getting in the way! Really annoying.

Also I remember when I used precise parts custom part to mate the mrk5 with the PXS, I noticed the optics of the pxs added false colour and was not good over x150mag. I found that a pair of baader zooms gave the same effect as the pxs with more graduations and better optics. Only negative of the zooms is the narrow fov at low mag setting.

The problem with astro gear is that you rarely can have your cake and eat it, theres always compromises.

#25 Paul G

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Posted 07 September 2013 - 10:37 AM

"Crashing Bino Syndrome" as it pertains to the Mark V, may be traced back to some not fully tightening the setscrew on the Quick Release adapter. The screw would then loosen further, fall out, and provoke tears.


There's no maybe about it, that's the only thing it could possibly be. Keeping the large easy-to-see, easy-to-grab screw tightened with a gentle twist is all that's required. I've never come close to dropping my Mark Vs. Someone mentioned it being too short. I lengthened mine with an inch of hard rubber fuel hose purchased for a few cents from an auto parts store.


Same here, have used the MkV extensively and never had a problem, but I always double check set screws or clamps on my setup.






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