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Understanding Binoviewers

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#26 Eddgie

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Posted 03 March 2024 - 09:23 AM

I have yet to dive into binoviewing, other priorities... got the best of me.

 

 

Question: What's the difference among the following... and which one would be recommended with Binotron 27 system and/or which one is included in the Binotron 27 SCT Super System...

 

 

IVB Power Switch Star Diagonal S2
IVB Power Switch Star Diagonal R1
IVB Power Switch Star Diagonal R2

 

 

.

It is an excellent question.

 

There are several advantages of the IVB over the power switch and overall, unless you have a dob, I would say the IVB/Star Switch is a better choice than the power switch on the binoviewr.

 

Here are the reasons why. 

 

First, the IVB Power Switch has a dovetail on the eyepiece holder which makes it easy to remove. This allows you to attach the binoviewer via a dovetail. In an SCT, this saves valuable light path length, resulting in far less aperture loss when using the built in reducer. 

Second, the diagonal has a built in dovetail that allows you to remove the eyepiece and attach the BV directly to the top of the diagonal. This also reduces light path, which is important for an SCT, but for a refractor, it reduces the moment of the binoviewer and eyepieces. This is important because when you have to put the binoviewer off to one side, the long moment of the binoviewer and eyepieces puts more torque on the retention mechanism on the telescope visual back (usually a brass compression ring) making it more likely to slip or break free and rotate. The dovetail also ensures that it won't fall out if this happens. 

 

Probably most important difference, is that you can use the IVB with regular eyepieces. so you turn one eyepiece into three eyepieces. The power switch on the BV is dedicated to the BV, and you get no other value from it. The diagonal allows you to use the power switch for regular eyepieces as well.  

 

The lenses in the diagonal are also much larger. The lenses in the power switch on the binoviewer are only about 25mm in diameter, making the well suited to 1.25" eyepieces, but they would vignette badly if used with longer focal length 2" eyepiece (assuming there was a way to use it this way, but there is not). For someone that wants to go back and forth between BV and single eyepieces, it is a excellent way to do it.  

 

This is my own opinion, and it is just an opinion.

 

The Power Switch binoviewer is at its best when used when the primary scope is a dob.  For someone that wants to binoview with a Dob, I recommend a power switch system with the Newt attachment as the absolute best way to do so. If they have a refractor that they occasionally use, they can still use it in the refractor, but it does not make going back and forth between regular eyepieces as easy as the diagonal power switch.

For hard core refractor users that want to banoview and would need to use a GPC or Barlow to reach focus, the Power Switch Diagonal and a binoviewer would be my top recommendation over buying the the power switch binoviewer.

 

For people with SCTs and refractors, while the T2 prism setup with a T2 binoviewer with short light path will give full aperture when using low power in most binoviewers, the power switch diagonal will have minimal loss and is worth the ability to quickly change to a 2" eyepiece when desired, and the low power arm will allow the 2" eyepiece to produce a much wider true field!!!!  Again, the system will lose aperture in low power, but the ability to get a much wider field and three useful powers makes the compromise a very good one. 

 

To me, the power switch diagonal is the most versatile for non-Newtonian users. For someone that uses them mostly in a Newtonian, the BV power switch will work elsewhere, but you do lose the ability to have a power switch with single eyepieces.  

 

I almost always recommend power switch systems, be it diagonal or binoviewer when a GPC or Barlow will be required for the binoviewer, and for people that use Newtonians and observe only with SCTs and Refractors, I would recommend the power switch diagonal as the best choice. Better to buy the BV a la carte and the power switch diagonal if you don't intend to use it in a Newtonian.  


Edited by Eddgie, 03 March 2024 - 09:23 AM.

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#27 mmalik

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Posted 03 March 2024 - 04:48 PM

Better to buy the BV a la carte and the power switch diagonal if you don't intend to use it in a Newtonian.  

 

Eddgie, much appreciate the (very) detailed writeup. My primary use case will be a refractor. In that case if I were to get a 'Binotron-27 à la carte', which one of the following diagonals should I complement it with? My question is what do S2, R1 and R2 mean exactly? Thanks in advance. Regards

 

 

IVB Power Switch Star Diagonal S2
IVB Power Switch Star Diagonal R1
IVB Power Switch Star Diagonal R2


Edited by mmalik, 03 March 2024 - 04:52 PM.


#28 Blueox4

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Posted 03 March 2024 - 08:15 PM

From the Manual at Russ’ website…

 

”Which Power Switch Star Diagonal To Choose?

There are several versions of the Power x Switch Diagonals available. The information provided below should allow the proper diagonal to be selected. We also produce an IVB Star Diagonal with no Power x Switch priced at $249 (Contact us for more information). Magnification factors were derived during testing with a C8 SCT and a Takahashi FS102 Refractor utilizing single eyepieces or a Denkmeier Binoviewer. These magnification factors may change with use of other binoviewer brands. Information indicating the amount of focuser travel for #R1 and #R2 is provided. This data will allow the refractor owner to select the diagonal that will work best in their telescope. Generally, #R1 should focus in all three magnification ranges when used with a binoviewer in almost all refractors. #R2 requires a larger range of focuser movement to cover the 6 magnification modes that are possible with a binoviewer. Weight may also be a consideration when choosing between #R1 and #R2 and such specifications are provided in this manual. Diagonals #S2, #R1 and #R2 include the Dovetail Connector. Information on the Dovetail Connector is also provided in this manual”

 

https://www.denkmeie...34f60db63d9.pdf
 


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#29 Blueox4

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Posted 03 March 2024 - 08:19 PM

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