The magnification of the Binotron will depend to some extent on the configuration but it will not very much.
The powerswitch pretty much mandates the use of the OCS, which behaves like a Barlow, and like a Barlow, the more space between the lens and the focal plane, the higher the magnification.
When used in a refractor with a standard 2" diagonal, the OCS is screwed into the filter threads on the diagonal nose piece and the BV is used in the normal manner with a 2" nose piece inserted into the eyepiece holder. In this configuration, the powers of the power switch will be 1.4x, 2.4x, and 3.1x
If you have a 2" diagonal with a nose that attaches with an M48 thread, that nose can be removed and the OCS can be screwed on to the front of the mirror box, and in this configuration, the power switch positions will give 1.3x, 2.3x and 3x.
Likewise, when the binoviewer is used with a Newtonian, the power factors will be determined by how much (if any) you need to extend the Newtonian Extension tube to reach focus. With no extension, the powers will be 1.3x, 2.3x, and 3x, but most mass produced Dobs will not be able to reach focus with the stock focuser with the extension tube in its shortest position. If you have to extend the tube to reach focus in low power, that will raise the magnification and 25mm of extension (which is probably about right for most mass produced scopes) will raise the powers to 1.4x, 2.4x and 3.1x.
For refractors and slower dobs, you can get buy with the 37mm OCS, but my advice would be to always get the 45mm OCS and with fast Dobs, it is really kind of important to use the 45mm or you can be working with an aperture loss in low power mode. Even with the 45mm, you can loose some aperture with very fast systems, but the loss will typically be minor and it is a good tradeoff for the lower power you can get, but I highly recommend that the 45mm OCS be used for
reflectors f/5 and faster. Also, if you sell, the 37mm is not going to limit your market opportunity. Bottom line, whether you think you need it or not, I recommend the larger OCS.
And last but not least, if you are going to work with a refractor and only a refractor or SCT, there is another option you should consider!
Denkmeier also sells power switch diagonals and this has many benefits over using a standard diagonal.
Now the nice things about the power switch diagonal is that it allows the use of any binoviewer and when used without the binoviewer and the OCA, you can put a 2" eyepiece holder on to the system and now have three powers with one eyepiece. Unlike the very small clear aperture in the binoviewer power switch, which can only be used with the binoviewer, the power switch diagonal has a much larger aperture on the lenses so if you use it with all by the longest focal length eyepieces, without vignetting.
So, it is an option that most people don't consider because they want the ability to use it in any telescope, but if you are a refractor or SCT guy, it is a very important option.
Here, you would not be affected by resale, because if you used a non Denk BV, you could sell the BV on its own, and you could sell the Power Switch Diagonal on its own and since you could use any BV you wanted, you have a lot of flexibility.
If I were only using it in refractors or SCTs, I would just but the R1 power switch diagonal and a binoviewer like the new Maxbright II or something like the BVs Dennis sells. That is because resale on these will be better than if you just tried to sell a Binotron A la carte. Best resale on the Binotron is when it is a system with 45mm OCS.
Edited by Eddgie, 22 October 2019 - 09:57 AM.