While the telescopes that scan the stars in the night sky all look pretty much alike, those that study the star in the daytime sky -- the Sun -- can be quite fanciful. Their tall towers provide sharper images of the Sun while helping keep the telescopes cool. Clockwise from top: The fairy-tale Einstein Tower in Potsdam; the Dutch Open Telescope, which looks like a Martian war machine from "War of the Worlds;" the Jetsons-like Solar Observatory Tower Meudon; and a modern-day obelisk, the Dunn Solar Telescope in New Mexico. [Astrophysikalisches Institut Potsdam; 2pem; Plindenbaum; National Solar Observatory]
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It’s hard to miss the research telescopes that study the night sky. Just look for a big dome with a couple of giant shutters, and there’s sure to be a telescope underneath.
But the telescopes that study the daytime sky are a little harder to pick out. Their enclosures can be far more fanciful. One looks like a modern take on an Egyptian obelisk, for example, while several look like airport control towers. There’s one in France that looks like the Jetson’s apartment building, and one on a Spanish island that looks like a Martian war machine from “War of the Worlds.”
All of these telescopes were built to watch the Sun, which presents some special problems. The main one is heat. As the ground warms up during the day, it radiates heat into the sky. These “heat waves” blur the view. So many solar telescopes are built atop tall towers — hence the odd designs. And one, in California, sits atop a lake, which stays cooler than the ground around it, so it radiates less heat.
Because they’re looking at the very bright Sun, solar telescopes generally have long focal lengths, so light has to travel a long way from the top of the telescope to the scientific instruments. Some telescopes have an open framework to keep that long pathway from overheating, while in others, the pathway is sealed up and the air is pumped out.
These techniques help astronomers study our star in great detail — which is about to get even better. More about that tomorrow.
Script by Damond Benningfield, Copyright 2013