Posts Made By: Donald Durbin

Hi Tim,

I own Burgess, Denkmeier, and Siebert 22mm 1 1/4" binoviewers, I also own a pair of Siebert 45mm Elite 2" binoviewers.

To the best of my knowledge the binoviewers that you mention come from the same Chinese factory. Some of the earlier ones were in the range of 17 to 18 mm clear aperture. They have since been opened up to 20 or 21 mm clear aperture. Please be aware that there are many different methods by which people measure clear aperture. I think when people are talking about 23mm clear aperture, they are speaking of the aperture at the base of the binoviewer.

No one that I know of is changing out the beam splitter or prisms from the original equipment, so that would indicate that they all have the same internals.

The Baader version has a few Baader add-ons like the Baader Glasspath Compensator and the Baader diagonal. I have not seen a pair up close yet but they are interesting enough to make me want to take a look at them. I do not think they come with a pair of EPs but I could be wrong about that.

There are other versions that come with EPs and basic optical correctors.

What type of scope are you going to use them with?

Don Durbin

Hi Adolfo,

Sounds like you might be missing a piece for focus in a refractor. The Multi OCS part should be threaded into the binoviewer. There should also be a separate piece that screws into the diagonals filter threads.

The OCS is a focal reducer. It purpose is to bring down the magnification that you get when you screw the other piece into the diagonal. That piece is actually a Barlow element.

Take a close look at the 2" Multi-Purpose OCS. There should be two pieces there. One piece will have a label on it that says 2" Multi-Purpose OCS FMC. If you hold this element up in front of a light bulb in your house the light bulb will look bigger. The other element is probably not labeled. If you hold it up in front of a light bulb, it will make it look smaller.

If you do not have the second element you can use a 2" Barlow in front of the diagonal.

You should get two ranges of power. One with the 2" Multi-Purpose OCS in front of the binoviewer and one without it.

The real trick to reaching focus here is the Barlow element in front of the diagonal.

Don Durbin

Hi Mark,

One of the most common experiences most people have with binoviewers is the perceived change in the size of the object you are observing. If you close one eye and use the binoviewer in Cyclops mode and then suddenly open the other eye the object you are observing seems to increase in size by 20% or so. This is assuming you can easily merge the images. Some small percentage of people do have trouble with that.

The next advantage is lack of eye strain. I have heard many people comment on losing track of time while checking out all the features of the moon with both eyes open. You can get lost in the view only to realize that it is suddenly cold out and your back hurts because you have been bent over looking through the binoviewer for 45 minutes or more. When binoviewing most people learn quickly to bring a chair and get comfortable.

I think the advantage I just described also directly translates to another advantage in longer viewing allows your eyes a better chance to adapt to the current conditions.

The 3D effect is also a real crowd pleaser, but I think ,most people will say that it goes away a bit as you become more accustomed to binoviewing. At least it has for me.

For me, binoviewers improve the quality of eyepieces. I think this may be because minor imperfections perceived in only one eye are cancelled out by the view through the other eye. My own personal opinion is that binoviewers make mediocre eyepieces good, good eyepieces great, and great eyepieces become extraordinary.

Don Durbin

Michael,

The binoviewer probably will not come to focus with the 1.9X corrector alone. However, a 1 or 1.5 inch tube with filter threads is probably all it would take to make this work with your DOBs.

There are also correctors out there for $69 or $79 with less magnification that will allow your binoviewer to focus.

My Burgess binoviewer does come to focus with the stock 1.9X in my 8" Orion Atlas, but it is a close thing.

Don

The 22mm Blacknights have diopters.

Here is a three-some.

Don

Here is my SiebDenk. Its a Denkmeier premium binoviewer with a Siebert Multimag OCA.

This combination will do a near zero magnification in a reflector without entering the light path.

Don

John,

I have a 1 1/4" SE Denk Star sweeper that I use with my Burgess in my C9.25. It is an excellent combination. The a 1 1/4" SE Denk Star sweeper has standard 1 1/4" filter threads and screws right into the bottom of the Burgess.

Do not get the Denk 2" SE StarSweeper version as it screws into the Denk custom threads and will not mate with the Burgess.

Another solution is the Siebert focal reducer which also screws right into the Burgess binoviewer. I think Siebert has two different power optics that he can put in there. I have the one with less power.

They both give a very nice wide FOV.

Don

Hi Wingko,

The Denk Power switch is threaded specifically for a Denk binoviewer. It screws in where the nosepiece screws in.

Denkmieir does make a few different Diagonal power switch combinations that will work with your Televue.

Don

Bennett,

I have had some success with high powered EPs, but the conventional wisdom is 10mm EP are a good high power. I always push things a little more and I have a pair of 9mm HD Orthos that I like. I also have a pair of 4.8mm Naglers but when you get to that power, merging the images can be a bit of a challenge.

Don

Jim,

Put the 1.9X adapter lens in the front of your 1.25" diagonal and you should be able to reach focus without any problem. The magnification will probably be around 2.5X.

Don Durbin