Improved Reflecting Telescopes

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Can you tell the difference between these two telescopes?

I’ll give you a hint. They are both reflectors. I know I wrote before that you’ll normally find the eyepiece (the little bit tacked onto the telescope tube) on the side with reflectors, but as you can see here, this isn’t always the case.

Here’s another hint. The mounting setup isn’t the difference I’m talking about. I realize the most obvious difference is probably that one is on a “fork mount” (right) and the other is on an equatorial mount (left), but I’m thinking of something related to the optics.

Don’t worry, we’ll talk about these two mounting systems in a later post.

So, can anyone venture a guess and tell me what’s different about these two telescopes? Continue reading

Telescope Powers

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Have you seen one of these guys before?

You probably have, even if you don’t recognize this brand-new innovation. This is the European Extremely Large Telescope, or the E-ELT. I know, imaginative name, huh? Anyway, it’s not all that different from one of those white observatory domes you’re used to seeing.

Astronomers keep building new observatories. They keep putting new telescopes into space—Hubble, Spitzer, and James Webb, to name a few. But the common goal of all the telescopes they build is to make telescopes that are as big as possibly possible.

Why? I mean, are astronomers just huge braggarts that like to impress us all with their big toys?

Well…I’ll admit that we astronomers have a lot of fun with our toys. But we need huge telescopes for a much better reason than bragging. Continue reading

Refracting & Reflecting Telescopes

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Right next to light, the telescope is an astronomer’s most valuable tool. There are so many different varieties of telescopes, it can be hard to keep them all straight. But they can all be sorted into a few basic types, and that makes choosing one a lot simpler.

Two very common types are reflectors and refractors, and each one in the image above is one of these. You can tell a reflector by its cylindrical design. They all look like cylinders, you say? Well…refractors are a little bit different.

Take the two telescopes on either end of this lineup, for instance. These two—the far left and the far right—are refractors. And you may notice that, unlike most of the rest, they’re not perfect cylinders.

Look closely. You’ll see that, not only is the end pointing up a bit wider than the rest of the telescope, but there’s a little tiny piece tacked onto the end. That same little tiny piece is tacked onto the side for the reflectors.

Every reflector and every refractor can be recognized by these basic qualities. But what they do with light is more important. Continue reading