Wednesday, 29 June 2016

The Bino-Dobson

As I already explained, one of the main problems that we, visual astronomy observers, have to confront is the desire to see more. Moving to a dark sky always helps a lot but even then our hunger for more can't be satisfied fully. Why can't I perceive that dustlane in that distant galaxy while my friend with his bigger telescope can? Why doesn't that nebula reveal those delicate filaments which I've seen on a photo? 

So in the end, many of us take the great leap forward and sell our telescopes in order to buy a bigger one. Which will keep us happy for a while until we're once more disappointed because also that bigger scope turns out to have its limits. At this point the astronomy community becomes divided. There's one half that resigns because of financial or practical reasons. Even if they can afford an even bigger telescope, where can they store it? Or how would it still be possible to transport such a monster to their preferred observation site? Or what would be the sense of buying something so big that it takes an hour to set up?

Then there is the other half. Those that never give in, regardless of the cost or practicality. They'd give an arm and a leg just to see that extra nebula filament with their own eyes. Yes, I have to confess... I'm part of this group, the group with unstoppable "aperture fever" (referring to the aperture of the telescope, or in other words the size of its lens or mirror). I used to own a respectable home-built 18" (46cm) Dobsonian telescope, which has given me many satisfactions for almost 10 years. But unfortunately it wasn't enough. Moreover, I experienced ever greater difficulties observing with one eye only. It's terribly tiresome and doesn't give you nearly as many satisfactions as observing with both eyes, such as with binoculars. The feeling of immersion, really "being there", floating through space without limits or boundaries that binocular observation offers can never be obtained with a single eyepiece, even the fancy ones with their 100° field of view. I've experimented for many years with all kinds of binoviewers, which split the light beam of a telescope in two so you can look with both eyes. I've used the cheap ones, the expensive Denk II and I've even been the proud owner of a gigantic 2" Siebert. In the end, none of them, not even the 2" model, satisfied me because they always resulted in a compromise with too many disadvantages such as light loss (even with the 2"!) and an undesired magnification increase. 

Hence the great leap forward: a binoscope. This is in fact two 18" Dobsonian reflectors glued together as it were, which you can use with both eyes like true binoculars, albeit that they are a little bit bigger. This time no more compromises and the true performance of a 25" to even 32" (faint objects) telescope! The only drawback is its size and above all its complexity to use. Let me make this clear: this is NO telescope for newbies or for people who don't like to collimate or fiddle with their telescope. This must be the most complex telescope design on the amateur market and I can assure you that aligning all of the mirrors is not child's play. But it has its compensations, such as an image so bright, rich, infinite, contrasty and even 3D-like that no other telescope could possibly compete. Perhaps I've finally found the telescope that will cure my severe case of aperture fever? Well, if this one won't, I don't think any telescope would. 

To conclude I'd like to express my sincere thanks to Mr. Otte, the builder of this amazing instrument, for his incredible craftsmanship, his personal and dedicated service and last but not least his friendship. It's a real pity that my scope was the last one that he's built and that he's giving up his telescope manufacturing company because it's only because of men like him that we amateur astronomers can truly enjoy the sight of the heavens.

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