My Telescope

6 luglio 2012

I started with a small 60mm refractor, which kept me happy for about twenty years. It was the perfect instrument to learn about the sky and I dare say that I used it up to its very limits. Then, as often happens, I got a severe stroke of what astronomers call “aperture fever”. The larger the lens or mirror of a telescope, the more you can see. And I wanted to see a lot more. So I bought an 8″ Schmidt-Cassegrain, the dream of my youth. But then I realised that what used the be the nec plus ultra of the amateur astronomer in the eighties, had since many years been surpassed by a new phenomenon: the Dobsonian telescope. Its concept is very simple: it’s a Newtonian (mirror) telescope made out of wood which lacks all of the electronic toys that all of the other modern telescopes have, such as an automatic object search and automatic tracking. But… the Dobsonian offers an aperture size which you could only dream of previously at a very affordable price.  I bought a 14,5″ Dobson and it felt like opening my eyes for the very first time. That’s how impressed I was… in the beginning. I hardly dare admit it, but I still wasn’t satisfied. So eventually I built my own 18″ Dobson.

This is most of the material I used. Doesn’t really look like a telescope, does it? :-)




But slowly, putting the pieces together, the structure emerges.





This is the mirror box, with the mirror support cell in place. Behind the cell I’ve installed two large cooling fans because it’s vital to keep a telescope mirror at ambient temperature to avoid unnecessary turbulence. The larger the mirror, the more important this becomes.


A couple of layers of paint…






…and DONE!





Here’s a view of my treasure: the high-quality 18″ Galaxy Optics mirror. It’s the “eye” of the telescope and it’s capable of capturing about 5.300 times more light than the human eye. or in other words, with this mirror you can see objects in the sky which are 5.300 times fainter than what you can see with the naked eye. Because contrary to what is generally believed this is the main task of a telescope: capturing as much light as possible. Most people think that a telescope has to magnify as much as possible and that’s it. But that’s just a myth because a lot of objects are actually quite large and don’t require a lot of magnification at all. It’s just that they’re so faint that the naked eye can’t see them. Then again, the larger the optics, the more you can zoom in on the object before the image becomes too dim.

And finally…  the telescope in its new, Italian environment, proudly standing in front of the shed I specifically built for it:

After all of these years of observing, I got tired of doing it with one eye only. I find it tiresome having to close one eye all of the time and feel that it doesn’t let you see all there is to see. There are many binoviewers on the market, which allow you to observe with both eyes. But unfortunately most of them make you lose a lot of light and the image becomes a lot dimmer than with one-eyed viewing. Therefore I invested in the 2″ Siebert VP Echelon, which has an aperture unmatched by any other brand and for the first time I believe that there doesn’t have to be any penalty for wanting to observe with both eyes.

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