Extremely Large Telescopes? Yes Please!

Approval has been given for the Extremely Large Telescope, a 21st century, ground based instrument. It will be located in Chile's Atacama desert, which is about the best place on Earth to site an expensive telescope. This area is extremely dark and almost perfectly cloudless, both important considerations. After all, there is is little point to building a high tech instrument in an area where it can't be used!

Full story here.

The telescope will feature a 40m primary mirror, and cost around 1 billion Euros. This makes it the largest and most expensive ground telescope ever. The James Webb Space Telescope is far more expensive, but it has to be launched into orbit, greatly increasing the cost. Generally, a ground based telescope costs 1/10th as much as a space based one of similar size. Now, an orbital telescope with a 40m primary mirror would be an incredible instrument, capable of seeing just about anything. However, in today's economic climate, such a device is unlikely to be funded. Therefore, we must make do with telescopes on the ground.

Assuming it is funded, the telescope should be ready by 2022.

I must confess a certain disappointment. The primary mirror will be made up of 800 individually controlled segments, which is a triumph. However, I was hoping this next generation unit would incorporate liquid mirrors. A liquid mirror can theoretically be almost any size, and at a fraction of the cost of traditional mirrors. By using magnetic fields, the curve of the mirror can be adjusted in very tiny graduations, allowing for a wide range of focal lengths. This lets you zoom in and focus on objects at greatly varying distances. However, a liquid mirror of this size is untested, and thus I'm not too surprised it wasn't incorporated.

One day we'll see liquid mirror telescopes with 10,000m wide collectors. You can see just about anything you want with that.

 

1 Response

  1. Galileo did not invent the teoelcspe. That is usually attributed to a Dutch spectacle maker named Hans Lippershey (Anton Van Leeuwenhoek was inventor of the microscope, BTW).Galileo was among the first to build teoelcspes, though, and the first to report on observations of the planets using one.His most important planetary discoveries were the phases of Venus and the moons of Jupiter. Both observations supported the then-controversial (heretical, in fact) theory of Nicolas Copernicus that the Earth and the other planets orbit the sun. The changing phase and size of of Venus are indications that it is moving around the sun. The moons of Jupiter were significant because they were clearly orbiting Jupiter, while the belief at the time was that everything revolved around Earth.He observed Saturn but his teoelcspes were not good enough to resolve the rings. What he saw was a large blob on either side of the planet, which led to to say Saturn was triple .Not sure what you're asking about first document facts of the planets . Mercury, Venus, Mars, Jupiter, and Saturn, being visible to the naked eye, were known before recorded history.

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