The New Childrens Encyclopedia

EYE SPY SPACE

■ Overall height 81 ft (24.6 m)
■ Total moving weight 300 tons (270 metric tons)
■ Total weight of glass 16 tons (14.6 metric tons)
■ Location 13,800 ft (4,200 m) above sea level on
Mauna Kea, Hawaii

The largest optical telescopes today are

the identical Keck I and II, each with

33 ft- (10 m-) wide mirrors. They are

on an extinct volcano in Hawaii.

Their telescopes are linked so that the

light they collect can be combined.

Giant air conditioners run constantly

during the day, keeping the dome

temperatures at or below freezing.

Keck I and II
Largest optical telescopes today

■ Height 432 ⁄ 3 ft (13.3 m)

■ Weight 23,855 lb (10,843 kg)

■ Mission length 23 years

■ Location Earth orbit

Launched in 1990, the world’s most

famous space telescope has a 7^1 ⁄ 2 ft

(2.4 m) mirror. It is named after

American

astronomer

Edwin Hubble,

who showed

that the universe

is expanding.

Hubble space observatory

Famous NASA-ESA observatory

■ Length 72 ft (22 m)

■ Weight 14,300 lb (6,500 kg)

■ Mission length 5–10 years

■ Location 1 million miles

(1.5 million km) from Earth

In 2013, the James

Webb Space

Telescope will

replace the

Hubble Space

telescope. It will have a

21 ft (6.5 m) mirror

(nearly three times bigger

than Hubble’s).

James Webb

Largest space telescope

■ Size 27 dishes, each 82 ft (25 m) across
■ Length of each railroad arm 13 miles (21 km)
■ Location Socorro, New Mexico

The Very Large Array is currently the

world’s largest radio telescope array,

consisting of 27 dish

antennae. The dishes

can be moved

along the arms

of a Y-shaped

railroad

network.

Very Large Array

27-dish radio telescope

■ Length 451 ⁄ 3 ft (13.8 m)

■ Weight 10,560 lb (4,800 kg)

■ Mission length 10 years

■ Location Earth orbit

Today, large space observatories, like

Chandra, are used to study very hot

X-ray objects such as supernovas,

white dwarfs, and active galaxies.

X-rays are captured by four pairs of

cylindrical mirrors.

Chandra

Most powerful X-ray observatory

■ Size 350 dishes, each 20 ft (6.1 m) across

■ Location Hat Creek, California

Currently under construction the array

is planned to contain 350 dishes inside

a^2 ⁄ 3 mile- (1 km-) wide circle. They will

be linked and act as a single dish to

study the distant

universe

and

search for

alien life.

Allen Telescope Array

350-dish radio telescope

■ Height Seven 27^1 ⁄ 2 ft (8.4 m) mirrors

■ Total moving weight more than 1,100 tons

(more than 1,000 metric tons)

■ Location Cerro Las Campanas, Chile

Due to be completed in 2017, the

Giant Magellan

will produce

images ten times

sharper than the

Hubble Space

Telescope.

Giant Magellan

Seven mirror optical giant

SPACE

Each main mirror is

made of 36 segments

that act like a single

piece of glass.