Tuesday, 11 May 2010

Size Matters

Look at this beast. It is a 12 inch, Dobsonian, reflector telescope and it stands almost six feet high when on end. Right now, it is pointing at the ceiling and taking up valuable space in the living room.

Unlike many other things in this world, the bigger the telescope, the better it works, because the larger the parabolic mirror inside is, the more light it will gather and - consequently - the higher the resolution of the image will be. I chose this telescope because it was the biggest one I could fit into the back of a Volvo estate. If I had bought a 14 or 20 inch mirror, I would need a step-ladder to look through the eyepiece at the top of the tube.

It is really designed to pick out the feint nebulosity of distant star-clusters and galaxies in deep sky - it is a deep-sky telescope. If you insert a high magnification eye-piece though, it will bring you to within about 200 miles of the moon's surface, and you can take an unguided tour of it's mountains a plains as if you were flying over it in a small spacecraft. When you look at the moon through this thing, the image is so bright that you have to use a smokey filter to cut down on the glare coming up from the layers of dust, and only about 20% of it is visible at any time.

But yes, I made the classic mistake that so many novice astronomers make who live in a small apartment in town - it is too big to conveniently carry downstairs and pop into the car for a trip to the dark countryside, so I really need to sell it and get something a little more compact, like an 10 inch Matsukov, which doubles the effective focal length by passing the light through a hole in the primary mirror, in a 3 foot tube.

I know that I will have to accept a lot less money than I paid for it, but be warned - buyer collects. It would be good in the dark, French countryside... Any offers?


  1. For the moment you must have a fabulous view of the ceiling!

    I'm not often jealous, but I'm slowly getting there over this. I'd love one of those. Even with my meagre binoculars it's wonderful looking at the moon. I can hardly imagine having something quite SO powerful to use.

  2. p.s. That really is a big bugger. How much does something like that cost? Or sell for? Or both!

  3. I spent £800 on the scope, plus another £300 on eye-pieces and filters (there are some fancy filters that allow you to see much more of the hidden veils, coated in rare metals and minerals...)

    You can have it for £500. Can't say fairer than that Guv. I'd be biting me own hand orf. Get in touch and we'll come to an arrangement. The Universe could be yours...

  4. p.s. The finder scope on the side (black) is probably a lot better than the average binocular, and could be used as a telescope in it's own right!

  5. Hmm. Looks to me like someone is overcompensating. ;-)

  6. You're not the first person to suggest that, Carol. I was looking through the window at a large spotting scope in town a few years ago, when a lady friend came up, looked at what was fascinating me and said, "So, a bit wanting in the trouser department, are we?"

    There's no psychological connection, I assure you. Now my gun collection, on the other hand...