Desktop Telescope
I went to Fry’s this weekend and walked out with a telescope. Yes, I bought a telescope on impulse but I simply couldn’t resist. This isn’t just any telescope though; this is a truly “Desktop” telescope! Seriously, the tube isn’t much bigger than a liter bottle and I can pick the whole thing up with one arm easily.
I love it.
It’s made by Celestron and is marketed as a “first scope” and at 50 bucks it’s a steal. First off I think it’s really cool they covered the tube with the names of old astronomers. I remember at MIT that Killian court (the main courtyard with “the dome”) had the names of scientists lining the upper trim of the stone walls. As corny as this sounds, it was inspiring. It was inspiring to finish a test or finish learning some new concept and walk out through that court and see those names… Archimides, Darwin, Newton, and Copernicus. There were literally a hundred of them lining the entire courtyard, I felt like I was a part of something bigger, something important. In a smaller way, that is what this telescope does. This telescope isn’t much stronger than what Galileo used, isn’t it just as amazing?
Ok, I got side tracked, I often do. Now for the specs of the scope, it has a 3 inch mirror as its base and comes with 20mm and 4 mm eyepieces. These equate to roughly x15 and x75 power eyepieces. The optical quality of the scope is sound but the 75 power eyepiece is really too much for this caliber of scope. That being said, it’s still awesome! Remember, it’s NOT the Hubble. It’s not the Hubble and I don’t live in the desert of New Mexico. Nevertheless, Sarah and I took it out and immediately saw the rings of Saturn! Saturn’s rings are very thin right now and the image still has significant aberration but we could definitely see the rings. When Jupiter comes back out it will also be able to image the 4 Galilean moons and the planet’s disc. This scope is really mostly for viewing faint star clusters, bright nebula and globular clusters. I can’t wait to spend more time with it.
So this telescope is a reflector type telescope. The image comes from a mirror on one end that focuses lots of light right onto the eyepiece. The size of the mirror doesn’t do any magnification; it just increases the amount of light the telescope can gather. It’s effectively like stretching out your pupil to the size of the mirror, or 3 inches The actual magnification of the image is done by the eyepieces. So what’s the reason you can’t just keep magnifying up (past 75 power for instance)?
Well there are two reasons. The first is because the mirror isn’t perfect. The mirror is effectively warped in some areas and that translates to an imperfect image at the eyepiece entrance. Also, there is only so much “light” in an image. If you magnify it, it gets duller and at some point the whole thing will get washed out.
Here is the kicker though, most faint things like nebula in the sky are actually quite big “angularly”. This means you don’t really need to magnify them all that much. What is really needed is a biggish mirror because nebula are very, very faint. This telescope is a great compromise between mirror size, mirror quality, magnification and price! What a great way to celebrate 401 years with the astronomical telescope.
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