Accessories - Binoviewer
The binoviewer allows to observe with both eyes, which is more convenient but losses some light due to additional optical elements in the light path and imposes narrower field of view. Usually binoviewers work better with large scopes, so I decided to get one for my C14 and I started with a cheap Burgess Optical Binoviewer. I think it is a very interesting experience to observe with both eyes. The two eyepieces supplied with the binoviewer (15mm) produced a bit too high magnification with C14, so I soon bought the second 20mm Expanse. Two 20mm Expanses worked much better with noticeably wider FOV.
When Obsession 18" became my visual scope I had to use 2x Barlow in order to come to focus. However, I soon got a set of shorter trusses for my Mallincam, which helped with binoviewer as well. With shorter trusses, I use 1.6x Barlow lens (SBW-1.6x OCA for binoviewer from Siebert Optics), and field of view is much better.
I don't use binoviewer every night, but I do use it fairly often. For me the most noticeable effect is that the field of view seems to be much larger. Not that it spans more of the sky, it is the same part of the sky, but somehow spread out ...