ELT construction moves forward

The European Southern Observatory (ESO) today signed contracts for the construction of the mirrors and sensor for its Extremely Large Telescope (ELT).

At a ceremony today at ESO’s Headquarters four contracts were signed for major components of the Extremely Large Telescope (ELT) that ESO is building. These were for: the casting of the telescope’s giant secondary and tertiary mirrors, awarded to SCHOTT; the supply of mirror cells to support these two mirrors, awarded to the SENER Group; and the supply of the edge sensors that form a vital part of the ELT’s huge segmented primary mirror control system, awarded to the FAMES consortium. The secondary mirror will be largest ever employed on a telescope and the largest convex mirror ever produced.

The construction of the 39-metre ELT, the largest optical/near-infrared telescope in the world, is moving forward. The giant telescope employs a complex five-mirror optical system that has never been used before and requires optical and mechanical elements that stretch modern technology to its limits.

Meanwhile it remains unclear when and where the Thirty Meter Telescope (TMT) will be built.

Groundbreaking — the literally blasting off of a mountaintop — took place today in Chile at the eventual site of the European Extremely Large Telescope (E-ELT).

Groundbreaking — the literally blasting off of a mountaintop — took place today in Chile at the eventual site of the European Extremely Large Telescope (E-ELT).

Once completed in 2024 this telescope will have a segmented mirror with a total diameter of 39 meters or 128 feet, the largest ever built.

Construction of the world’s largest ground-based telescope has been approved by the European Southern Observatory.

Construction of the world’s largest ground-based telescope has been approved by the European Southern Observatory.

No one should get too excited about this announcement. They still need to raise 90% of their funds to build it, and to do so they have to get agreements from the four member countries of the European Southern Observatory. It will be years, probably at least a decade, before this 40-meter truly gigantic telescope sees the light.

The coming blindness of astronomy

Fried Egg Nebula

The European Southern Observatory today released this infrared image today of what astronomers have named the Fried Egg Nebula. Taken by the Very Large Telescope in Chile, the picture shows the concentric dust shells surrounding a post-red supergiant star, thought to be transitioning to the next stage of stellar evolution called a yellow hypergiant. As the press release explains,

The monster star, known to astronomers as IRAS 17163-3907, has a diameter about a thousand times bigger than our Sun. At a distance of about 13 000 light-years from Earth, it is the closest yellow hypergiant found to date and new observations show it shines some 500 000 times more brightly than the Sun. . . . If the Fried Egg Nebula were placed in the centre of the Solar System the Earth would lie deep within the star itself and the planet Jupiter would be orbiting just above its surface. The much larger surrounding nebula would engulf all the planets and dwarf planets and even some of the comets that orbit far beyond the orbit of Neptune. The outer shell has a radius of 10 000 times the distance from the Earth to the Sun.

Yellow hypergiants are in an extremely active phase of their evolution, undergoing a series of explosive events — this star has ejected four times the mass of the Sun in just a few hundred years. The material flung out during these bursts has formed the extensive double shell of the nebula, which is made of dust rich in silicates and mixed with gas.

According to the science paper [pdf] describing this research, the stage of yellow hypergiants is a preliminary to the star evolving into a luminous blue variable, of which Eta Carinae is the most famous. In this next stage a star is thought to have a good chance of going supernova.

Though this image is truely spectacular, taken by a ground-based telescope of a star 13,000 light years away, what I find most significant about this image is its fuzziness. It reminds me of the kind of images astronomers and the public routinely accepted as the best possible, before the launch of the Hubble Space Telescope.
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Mature galaxy cluster found in young universe

A mature galaxy cluster has been found by astronomers at a time when the universe is thought to be only a quarter of its present age.

This discovery could be very significant, since astronomers think mature galaxy clusters need time to form, and shouldn’t exist in the early universe. “If further observations find many more [of these clusters] then this may mean that our understanding of the early Universe needs to be revised.”