WO Binoviewers

[Hitman77]

Hi folks. Looking at buying a se condhand pair of WO binoviewers to use with a 12" truss dob. I've been doing some research but keep finding conflicting info. I think there is an issue with back focus in my scope and I'm now wondering if purchasing them might be a waste of money. The sale only includes the binos, no barlow or ep's. That in itself isn't an issue as I have a x2 Revelation barlow and I was thinking of purchasing another 20mm TV plossl to use. Am I right in thinking that 20mm is about right? Also I have read that due to dimming DSO's might not be doable so I'm thinking they might be great for solar system and bright DSO like M13, M42 etc. If any of guys and gals could share with me why to go for it or why not to go for it I would appreciate mote experienced stargazers input. Cheers

[Beulah]

If you own the Skywatcher flextube truss tube Dob, there should be a second set of locking holes that someone had accidentally discovered works well with getting binoviewers in focus...

 

[Mak the Night]

I have used my WO bino with a Mak and plan to use it with a larger SCT very soon.

I use 32mm, 25mm, 18mm, 15mm and 12.5mm EP's with it and find it is good for everything from planetary/lunar viewing to Messier Objects. You should be able to order 1.6x and 2x Barlow nosepieces from FLO.

I don't know about using it on a telescope other than a Mak/SCT but a T-Adaptor like this Celestron may help between the bino and the telescope.

[brantuk]

20mm or 25mm wide angle eyepieces will be fine and you'll need a 1.5x barlow (I think that's what's in my WO bv's). Shorter refractors (400mm to 600mm FL) are a bit fussy with inward focus - sometimes there's just not quite enough to achieve focus. You'll have no trouble with them on Sct's and Mak's though which tend to have a lengthy focus throw in both directions. I understand from others that they can be used on dobs/newts - but I've never tried that particular combo myself.

The moon with bv's in an Sct is awesome - feels like you're flying a couple hundred feet up over the surface. And star fields take on a 3D like feel to them as if you're right in the middle of the stars. The WO ones aren't the best - but they are fabulous value for money in that price bracket - the next one being over £500. I wouldn't pay more than £40 - £50max for the ones you're looking at cos you can get that part brand new for ten or twenty quid more. You may be better off getting the whole set new including all the bits for around £220. Hth  

[Hitman77]

Thanks for the tips guys. The thread about extra holes is interesting although mines does not have them which is a shame

Andy

[Louis D]

I use the nosepiece from my Meade 140 2X barlow on my Arcturus binoviewer with my short backfocus dob just fine.  The view is sharp from edge to edge with no vignetting.  I use either 26mm or 32mm plossls, depending on how bright I want to make nebula appear.  They're bigger, but dimmer, in the 26mm plossls.  The 32mm plossls vignette due to the 22-23mm clear aperture of the binoviewer, but the center looks great.  I couldn't get either of the nosepieces supplied with binoviewer to work without tremendous distortion right to the center.

For a wider field of view, I use a 0.5x focal reducer about 25mm to 40mm behind the 2X nosepiece (the 2X is closest to the primary) using spacers.  It vignettes and introduces some field curvature, but the net magnification is only about 0.25x instead of about 3x.  The nearly 3 inch long nosepiece fits entirely inside the focuser, so no focus issues there.