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Stellarvue BV3: Binoeyes on the Skies

Posted by Rod Kaufman   01/20/2007 12:00AM

Stellarvue BV3: Binoeyes on the Skies
I've never enthusiastically embraced the concept of binoviewing. Perhaps it's because I've always been an observer with a trained eyeball dedicated to the cyclops mode and my non-observing eye is essentially in the "sleep mode". Or, maybe it's the thought of having a large kluge of a binoviewer with two eyepieces protruding from a weight-strangled focuser that's deterred me from the purported delights of a 3-dimensional viewing experience. Or, perhaps it's the thought of precious photons being lost in the transmission process from the primary lens or mirror with a pit-stop in the prism before reaching the eyepieces.

After a few "ho-hum" viewing experiences with relatively small scopes equipped with relatively large binoviewers on loan from fellow observers, I thought I would take the plunge and see if the new Sellarvue BV3 binoviewer would satisy my cravings for a new observing experience with my 16" truss telescope.

At a mere 19 onces, the BV3 binoviewer is a weight-saver. At approximately 5" in height it's the binoviewer equivalent of a "shorty" barlow. Add two supplied high quality 23mm 50 degree apparent field of view eyepieces and couple them with a high transmission 22mm diameter prism and you're ready for some serious observing, either planetary or deep-sky. I note "either planetary or deep-sky" because my scope would not come to focus with the binoviewer in place, either alone or with the supplied optical adapter and/or extension tube. I did need to add my own 2X power barlow for the binoviewer to focus, despite the claim on the Stellarvue website that the binoviewer will work with most newts.

With the barlow in place, I quickly experienced the joys of binoviewing. I observed M-42, the Orion nebula, from my home, and despite mild to moderate light pollution, the object appeared in a 3 dimensional form with billows of nebulosity evident together with six stars visible in the trapezium. I didn't expect to see the latter, given the less than optimum viewing conditions and the extra glass added from the barlow as well as the binoviewer.
Saturn floated effortlessly in the field of view with delicate shadings and bands evident on the globe and easily discerned divisons in the ring structure.
My impression is a binoviewer such as this one has the capability of high transmission despite the added elements of a barlow or optical adapter. I viewed M-81 and M-82 from my home through my 16" truss-dob and I was thrilled with the images.

Drawbacks? Yes there are some. Although the individual collets reportedly allow for very precise collimation and the individual diopter adjustments work well, the relatively narrow knurled focusing rings are hard to handle in cold weather. This is a quibble, however, because once they are set to the satisfaction of the observer, focusing is performed as usual from the primary focuser on the scope.

The instruction manual supplied with the binoviewer makes no mention of how to use the binoviewer with a newtonian telescope. The added caveat of the need for the use of a barlow with some newtonian telescopes should be included in the manual.

All in all, this is a high quality unit with excellent transmission characteristics at a very affordable price.
Two thumbs way up!

Click here for more about this subject. -Ed.