Binoviewer v binoculars - 20x100

[25585]

A question that niggles me. 

Having a rich field refractor 100mm OG (500mm fl), if I bought a binoviewer & another 25mm eyepiece (Vixen SLV) + neccessary whatnots to make the bv work, would the views be as good or better compared to (say) a Helios Lightquest 20x100 pair of binoculars?

 

[Chris]

It's a good question. Well assuming you don't need a glass path corrector with the BV's, both would give you 20x. The BV option will allow for different mags/eyepieces to be used and off course you'll have a more comfy 90 degree views when using a diagonal. The aperture will be effectively less with the BV's as you have 2x100mm objectives with the binos.

I've got a feeling the Lightquest would have a flatter field, I think I read they were close to the Lunt's in terms of flatness? Probably quite a bit of SA with a rich field achromat? assuming you have something like a Synta achromat.

[Wobbly Bob]

I have a pair of 100mm 90deg binoculars which have 1 1/4" openings for the more common eyepiece, just asking myself if I have double the aperture ? The view is three dimensional. The only real disadvantage is the weight.  

[Peter Drew]

For low power wide angle views I don't think the binoviewer will be as good as there is considerable light loss through the beam splitter  prism. Binoviewers come into their own when used for bright objects like solar, lunar and planetary.   

[Louis D]

Apples and oranges in many respects.  If the refractor needs an OCA to come to focus, you may not be able to reach as low of a power as in the binocular.  The view will be dimmer as well.  As stated above, that doesn't matter for bright objects.  There's also the matter of viewing comfort if the binoculars aren't right angle viewing.  Also, are either the binocular or refractor objective(s) achromatic, ED, or APO?  Better glass will mean cleaner views even at low powers.  Let's not forget flexibility.  The binoviewer can have all sorts of eyepieces used in it to yield high powers, ultra wide AFOVs, long eye relief, etc.  Does the binocular have interchangeable eyepieces?

[25585]

It's a Televue Genesis. So good for flat but has Ca on brighter objects. Theoretically TV's bv should be best in it as it's made for all types of scopes including their refractors. Mine is an APO Petzl I believe. 

The diagonal comfortable viewing & having a mount already mean I only need to buy a bv. I have bins 11x70 so 20x & 25x are the mags I would use. Beyond that cyclops or my dob would be used.