Bino Viewer problem.

[banjaxed]

I have recently purchased an Astro Engineering bino viewer and a pair of 15mm Plossl eyepieces. A very kind member posted a copy of the original instructions on this site which were very clear and it looked like an easy task to get set up and focused. I used my 127 mak as it is not supposed to need a barlow or extension to obtain focus but all I am getting is a white light through the lenses however much I adjust the eyepiece focus or the telescope focus. Does anyone have any idea why this is happening or could the binoviewer be faulty ? Any help would be greatly appreciated.

[mikeDnight]

You could try it with a barlow between the scope and bv just to see if you can obtain a focus, then at least you'll know if the bv is working.

Edited January 20, 2020 by mikeDnight

[joe aguiar]

What's weird is a sct or mak norm doesnt need a Barlow.

Try each eye alone is it same thing?

U can also try the Barlow thing doesnt hurt to try

Joejaguar 

[banjaxed]

In case it helps anyone I have discovered that I can obtain focus if I use a diagonal. Now trying to find a way to use it on my Dob.

[Waldemar]

Most diagonals have a lightpath of about 4 inches (10 cm) Just get an extension tube of that length and you're done, or of course a Barlow would do the trick too

[Stu]

Were you trying to use it straight through? Perhaps not surprising that you needed an extension in that case, even a Mak will be designed to work with a diagonal I would think.

[Cosmic Geoff]

I have used a binoviewer successfully with my 127mm Mak and my 203mm SCT.

The key issue here is that the binoviewer adds around 100mm to the optical path. This is a major change in path length, and the focus mechanism of the Mak will cope with it if you wind it enough. Point the telescope at a very bright point target, eg Sirius or Venus, and wind the focus in the direction that makes the 'donut' smaller, till it comes in focus.  You will have to do the reverse to stop using the binoviewer.

Some telescope designs, eg the Newtonian reflector, will not cope with the extra 100mm path at all unless you can use a Barlow, but Maks and SCTs will all be fine.

[banjaxed]

2 hours ago, Stu said:

Were you trying to use it straight through? Perhaps not surprising that you needed an extension in that case, even a Mak will be designed to work with a diagonal I would think.

No I wasn’t using it straight through but it only works with a 45 degree diagonal and not with a 90 degree ?

[banjaxed]

I have tried every way with my Dob and nothing works so it looks like it will be just used on my Mak.