spartinix

Vignetting at the exit of a binoviewer, as opposed to at the entrance (aperture reduction), depends on the exit clear aperture, the field stop of the eyepiece AND how close its field stop is to the exit clear aperture of the BV (some baffle). When an eyepiece's field stop is low in its barrel and thus fairly close to the exit baffle (exit clear aperture of the BV), a sharp falloff can occur (sharp vignetting). From a certain distance, it is said that, in general, an eyepiece field stop can be 10% larger than the clear aperture of the BV without being noticeable or particularly annoying.

Some calculations for SCT's... https://www.telescope-optics.net/SCT2.htm

It's also possible that your eyes are not sufficiently parallel. A lot of people have a mild case of this condition. In such a scenario, a binoviewer which allows internal alignment and/or external collimation can be adjusted to compensate your eyesight. The binoviewer would then be conditionally aligned to your IPD only though (+/- a few degrees).

Short focal length eyepieces to reach high power, rather than long focal length eyepieces with a corrector, will surely be much more demanding on collimation.

"No idea what I did!" -It could be that your eyes finally got the image merged. To a certain degree the eyes will automatically merge an offset, but that will usually cause eye-strain and fatigue after a while. Regarding the merging in general; it has little to do with the binoviewer brand, source, price etc. Sure enough, some binoviewers can be bought in excellent collimation, but just like a telescope, a binoviewer can require re-collimating (even due to the transport to your house). The William Optics binoviewer, afaik, provides no collimation means though, so upgrading to Maxbright might be a good idea. The MBII was tested against far more expensive binoviewers and the differences were minimal, if at all there.

Hello Arneb The holders are one unit with the plates in which the screws visible in this picture attach them to the binoviewer. No threads; the holders must be bored out to ~31.7mm to accept 1.25" eyepieces or adapters to accept T2 eyepiece holders must replace them. The original holders are actually the best configuration to collimate the binoviewer easily (with the 3 screws connecting to the body). This is one mistake btw Nicu Barbieru made (see above). He asked me for designs for personal use but went commercial with incomplete designs and temporary collimation instructions I gave him. He stated in private that he would make the adapters himself so I figured I'd give him what I had at that point and he would figure out the adjustments for precise collimation. There's a bit more to it than just replacing the original holders to achieve good collimation though, so buyer beware. The original holders can be fitted with supreme quality Zeiss W-PL, S-PL, OPMI and Leica microscope eyepieces for the absolute best optical quality, in combination with a corrector or not (Powermates highly recommended). The only thing needed then is a telescope connection adapter, which is the easiest and least expensive part. In the meantime, a second project round is almost finished now with new designs and a new dovetail allowing shorter optical path. Anyone is free to contact me on the availability on updated designs and new parts regarding collimation as well. The binoviewers can not be purchased new anymore though, since the mothership microscope has been upgraded by Zeiss. Not that most adapted binoviewers sold were new rather than refurbished models but anyway.

Other eyepiece holders will not take care of crucial collimation, as they usually sit on top of some collimation system. Only binoviewers with a lateral collimation system like the Binotron make it really easy. Such a thing can be implemented though.

Yes, the path is easily 25-30mm longer, depending on the particular configuration. Here's the path of the mirror binoviewer.

Thanks! I started the second collective buying initiative for these. Prices should be very interesting. Contact me asap for joining.

Some pictures of the finished binoviewer. The designs are available for who wants to make/order parts. NOT for commercial purpose. The CAD software licence does not allow it. I'm keeping track of this. Also, there are vendors enough I'd say. They all sell secondhand stuff and charge way too much. It's much cheaper to do it yourself. PM me for advice and more information.

That part of Crete is indeed very dark. And if you can observe from a few hundred meters above sea level in that area you get the best of both worlds; great seeing as well as transparency. About 30 miles south is the island of Gavdos btw, which is arguably the darkest place in the EU. It's true, in some places here one can content himself with just a pair of binos or even a few hours of naked eye observing. Some of the Milky Way's dark clouds can be seen as if hovering in the foreground over de brighter sky background and Milky Way stars.

With my dob, I also just pull out the binoviewer and OCS/GPC out and in goes the eyepiece, with or without adapter depending on 1.25" or 2" barrel. I don't have a refractor or SCT but if I had, I'd have the choice to change fast between mono and bino IF I had two diagonals as in your case and if I were using an OCA/GPC. IF I had only ONE diagonal, then preferably a T2 diagonal, and IF I used a BV at native focal length without OCS/GPC, then I'd have the Quickchanger permanently mounted on the diagonal and use a ChangeRing/Clicklock combo to switch to mono. In both cases it's of course possible also to have two OCS's; between the bv and the eyepieces. I should have also mentioned the 'native mode' condition (if the OCS was a Barlow or Bravais lens it could be left for mono too of course unless for low power viewing).

Baader-Zeiss Micro M42 Bayonet dovetail-ring connection to mount on the original rotating ring connection with three M3 panhead screws of 5mm length (first screenshot). No binoviewer dissasembly required. The main advantage is faster switching between mono and binoview-mode, in particular for refractors and SCT's, IF used with Baader Quickchanger, T2-diagonal, and Clicklock eyepiece holder(s) and Baader ChangeRing (also dovetail-ring) for mono configuration. Baader has now introduced the M48 Quickchanger, ChangeRing and accessories; https://www.baader-p...ter-system.html Baader-Zeiss M48 Micro Bayonet dovetail-ring connection to mount on the original rotating ring connection with three M3 panhead screws of 5mm length (second screenshot). PM for cad files.

They are indeed very good. I've been using mine for a few months now, with microscopic eyepieces, and before, with a temporary homemade telescope-side photographc T-ring-adapter. A binoviewer too heavy is where it all started for me.

Some more pics and screenshots.

A while ago I decided not to buy a modified Zeiss mirror-binoviewer. As this model has been modified by amateurs for years I thought I'd give it a go myself. I ordered one from a Zeiss dealer, but they can also be ordered here for about 360; model 415500-1401-000: https://www.micro-shop.zeiss.com/en/uk/shop/search/binocular tube?page=3 Once received, I removed the 3 screws attaching it to the microscope deflector and started to measure it up for designing the modification parts. Initially I was only going to adapt the binoviewer on the telescope side only. After all, microscopic eyepieces come highly recommended and the hassle of switching eyepieces can be avoided by combinations of barlows, Powermates, Glasspaths or some powerswitch system. A few weeks ago I decided to modify it completely, as it was suddenly announced that this binoviewer plays nice with 27mm fieldstop-eyepieces after all. The telescope-side part arrived recently, it attaches to the original rotating ring at the back of the binoviewer. No removal of parts needed, and no loosening and tightening of a set screw to rotate the unit. The part has an internal M42x0.75mm 'T2' thread for most common accessories like 1.25" and 2" nosepieces and various OCA's / GPC's. The part has also an M48x0.75mm external thread which can accept M48 accessories, such as 2" extension tubes (no undercuts!) for 2" focusers. The adapter is 15mm in thickness. The eyepiece-side parts, the eyepiece holder sockets; accept the common Baader T2/1.25" eyepiece holders. These parts can get relatively expensive depending on the choice of material and finish IF you only have one piece made at some CNC-service. So, in a collective buying effort with some others I made the order for 5 pieces per modification part and even at that quantity, the bulk prices for these kinds of small parts gets ridiculously low. The prototype eyepiece holder sockets I received proved good, am now awaiting the actual parts. Feel free to pm me for the design files if you wish to go diy on this one (no charge). Some renderings of the complete model I made, with and without Baader Clicklock #2458100 1.25"/T2 eyepiece holders.