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Siebert Optics Binoviewers

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41 replies to this topic

#26 Tak North

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Posted 18 February 2014 - 11:52 PM

They should do a "reality" TV show about him!

BV Dynasty! :grin:

#27 REC

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Posted 19 February 2014 - 11:02 AM

Yeah for sure, he is a nice guy. After the BV discussion with him, he started telling me about the large 3" EP's he is making for the large professional observatories.

Can you imagine looking through a 50mm WA EP in a 50" scope..you talk about a "space walk" !!!
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#28 careysub

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Posted 19 February 2014 - 02:38 PM

...

I guess this would be a case for shortening truss tubes (or getting a second set of truss tubes) if you had a truss tube dob...


In a Newtonian, that is pretty much it.

From this day forth, all of my Newtonians will be built with a two-optic path length option.

For straight strut scopes this is quite easy, just make a set of struts cut-down by the required extra path.

Truss systems can be more difficult - some set-ups are difficult to vary the truss angle, etc. and a specific design feature included at build time might be helpful (i.e. how about an upper and lower attachment point for the cage, leaving the truss the same?).

#29 Chuck Hards

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Posted 19 February 2014 - 04:03 PM

Can you imagine looking through a 50mm WA EP in a 50" scope..you talk about a "space walk" !!!


Well, I've looked through a wide-angle EP in a friend's 70" scope. Though our club's 32" is technically closer to 50".

:grin:

#30 REC

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Posted 20 February 2014 - 08:58 AM

Wow, that must have looked awesome no matter what you looked at!

#31 faackanders2

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Posted 25 February 2014 - 06:18 PM


Can you imagine looking through a 50mm WA EP in a 50" scope..you talk about a "space walk" !!!


Well, I've looked through a wide-angle EP in a friend's 70" scope. Though our club's 32" is technically closer to 50".

:grin:


What did you look at in a 70" scope, and how much color did you see? I assume it was an observatory.

#32 TiSaph

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Posted 08 May 2017 - 03:52 PM

The exact BN25 light path is 115mm, due to the long eyepiece holders.

I don't see this talked about often.  Siebert lists the 100mm path length of the BN25s as their major advantage over the competition (at 115mm).  The Siebert comparison page shows that the Earthwin 26mm CAs with 115mm path length cannot produce any fully illuminated field in an f/5.2 scope, whereas the BN25s at 100mm path length can, as well as the Baader Mark V.

 

So how does that interplay with your report, and others (https://www.cloudyni...prisms-quality/) that the BN25s are actually 115mm path length?



#33 BillP

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Posted 11 May 2017 - 11:56 AM

Whoa Eddgie I didn't mean to set you up for an ambush! I am always interested to learn from debates between more experienced users, and I am always grateful for the time and effort you put in to sharing your knowledge Eddgie.

I think it is most likely the case that you almost always get better value from quality used equipment vs new. In the case with the Denk II vs the BNs, a more fair comparison would be between a used BN and used Denk II. Assuming that the price spread between new BN and Denkmeier equipment translates into a similar price spread in the used market, the BNs seemed hard to beat.

Having said that, in the case of binoviewers, I have a slight bias towards buying something new from a proprietor who I can call if anything comes up.

 

Eddgie makes some good points...as he always does bow.gif .  I would not consider it a bias against Sieberts if he happens to recommend other gear.  He is simply relaying his experience and preferences on equipment, as we all do.  And since he's owned many different binoviewers, his opinion has a bit more credibility than those who might offer opinions based on paper specs and having no experience.  Many of us end up using our binoviewers on multiple scopes.  As Eddgie points out, when you do that, adaptability becomes an issue that can save you a lot of frustration.  My binoviewers, WOs, have had me build a large assortment of adpaters and Barlows to have them come to focus with all my scopes with and without OCA.  So I certainly feel the pain he is describing, and he's just trying to offer you the honest wisdom of his experience, as all of us do.  So based on his experience with a lot of equipment, he has an opinion and is offering it.  If that means he is tending to recommend people in a certain direction, then that is perfectly valid as he is talking from his experience.  No foul whatsoever and absolutely no cause to question integrity!!!

 

As for me, I've had the WOs forever and have decided to upgrade in the next year as I find binoviewers critical for planetary observing with smaller apertures.  For me adaptability will be important as well as I do not want to go through what I do now changing configurations and adapters and Barlows so much as it makes observing less intuitive.  That being said, a Denkmeier or Baader brand are what I will be primarily looking at.

 

btw, since you value being able to talk to the vendor of a product you own, yes you can call Harry at any time.  But Russ of Denkmeier is also an easy phone or email away as well, and for Baader, the main US rep Bob Luffel of Alpine Astro is also an easy phone or email away, Al is always on the phone if you go with TV binos.  I used to talk with Harry when I had his gear but have not in a long time.  Russ and Bob I contact often.  So you have no shortage of brands where you can talk to the vendor at any time...it is not unique to Siebert.


Edited by BillP, 12 May 2017 - 10:53 AM.

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#34 tmaestro

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Posted 31 May 2017 - 07:30 PM

 

...

I guess this would be a case for shortening truss tubes (or getting a second set of truss tubes) if you had a truss tube dob...


In a Newtonian, that is pretty much it.

From this day forth, all of my Newtonians will be built with a two-optic path length option.

For straight strut scopes this is quite easy, just make a set of struts cut-down by the required extra path.

Truss systems can be more difficult - some set-ups are difficult to vary the truss angle, etc. and a specific design feature included at build time might be helpful (i.e. how about an upper and lower attachment point for the cage, leaving the truss the same?).

 

I seem to remember someone saying that they use a Sky Watcher collapsable dob for this reason.  They can lower the UTA on the struts just a little bit.



#35 rcg

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Posted 25 February 2019 - 11:35 PM

An alternative to the power switch is baader click stop zooms, supposedly designed with binoviewing in mind, 5 eyepieces? Granted that a used binoviewer will be cheaper than a new of comparative value if they are comparable. Looking at this

 

pagehttps://www.sieberto...comparison.html

 

shows a difference in what the optical path can mean for light transmission, although the effect of soft vignetting is debateable. The effective total necessary Optical path can be further reduced by using the T2 system to eliminate the nosepiece of the binoviewer and connect it straight to the diagonal, although that distance isn't specified, since it could change depending on the diagonal.



#36 rcg

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Posted 31 March 2019 - 06:43 PM

Should have my 2" seiberts by the end of April, will do a review on my scope/binoviewer combo this summer most likely.



#37 Albert P

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Posted 19 January 2020 - 03:00 AM

How are your Seibert's?

#38 GOLGO13

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Posted 31 January 2020 - 03:37 PM

I picked up some used Siebert black nights that come with the 1.25 multi mag setup.

 

Any advice on successfully using them? I've tried binoviewers in the past and wasn't able to really get them to work to my satisfaction. Whether it's how my eyes work or the units I had not sure.

 

When I mean successful I mean seeing a distinct advantage or getting them to work well in my scopes.

 

I do know now one situation was actually the scope's fault. The scope I had at the time had a custom flange made for the moonlite and it was too long. So the scope didn't have proper back focus.

 

 

The past ones were Earthwin (when they first came out) and William Optics.

 

My problem with the Earthwin was in my Dob something was off with the adapter. Like, things would be in my light path. It could have been my mirror was pushed down too far. They were OK in my refractor at the time, but I felt like the 10 inch was the primary scope to benefit from them and I returned them.

 

With the William Optics, as I mentioned it didn't have a proper chance in the refractor. But otherwise I just wasn't too impressed overall.

 

So giving it one more try to see how things go.

 

And by the way I like Eddgie's help and opinions! haha. Little harsh on him in the thread. I actually was looking at Denk IIs and was about to jump on one, but the Siebert came in pretty low cost and that worked better for me in my current situation. I also feel the Denk dudes were pretty crappy back when the whole earthwin split happened. So I'm a bit sour on them. Though I may have still bought one at the right price.



#39 GOLGO13

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Posted 31 January 2020 - 03:37 PM

Should mention I have not received these quite yet.



#40 GOLGO13

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Posted 03 February 2020 - 02:26 PM

Got the binos and they work well once I got everything figured out on how to use them.

 

Going to try getting another 16mm Brandon and give that a go.

 

I'm still not sure if I like binoviewers more than single eyepiece, but I'm going to give it another go. 

 

My left eye is pretty crappy, so I'm wondering if that has impact. But so far this is the best view I've had.

 

Also, I have plenty of backfocus with this system. It has the 1.25 multi mag OCA which gives 1x and 3.5x on the refractor. Seems to work pretty well. Have no tried it on my 10 inch dob, but I'm sure it will work. Though I think that's only one magnification from what I can tell.



#41 junomike

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Posted 03 February 2020 - 06:15 PM

Got the binos and they work well once I got everything figured out on how to use them.

 

Going to try getting another 16mm Brandon and give that a go.

 

I'm still not sure if I like binoviewers more than single eyepiece, but I'm going to give it another go. 

 

My left eye is pretty crappy, so I'm wondering if that has impact. But so far this is the best view I've had.

 

Also, I have plenty of backfocus with this system. It has the 1.25 multi mag OCA which gives 1x and 3.5x on the refractor. Seems to work pretty well. Have no tried it on my 10 inch dob, but I'm sure it will work. Though I think that's only one magnification from what I can tell.

IME they (Singe EP/BV) compliment each other as oppose to compete (with each other).

 


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#42 daslolo

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Posted 16 February 2020 - 03:55 AM

The funny thing is, I've owned my 2" Black Knights for 3 years now, but I've never really "used" them. Yes, I,ve had a look using an OCS, but putting an OCS on that system negates the benefits if 2" EPs with the resulting magnificatuion one might as well Use the Denk system with powerswitch and reducer.

It reaLly requiers a scope with about 300 mm of backfocus to get the 2" BVs with a 2" duagonal to reach native focus. I'm bulding such a scope now, at which point I will finally be able to "use" my Black Knights!

Did you finally use your 2" bino?




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