Great Observatories Explore Galactic Center
11.11.2009

Where can a telescope take you? Four hundred years ago, a telescope took Galileo to the Moon to discover craters, to Saturn to discover rings, to Jupiter to discover moons, to Venus to discover phases, and to the Sun to discover spots.

ROSAT Explores The X-Ray Sky
8.10.1996

Launched in 1990, the orbiting ROSAT observatory explored the Universe by viewing the entire sky in x-rays - photons with about 1,000 times more energy than visible light. This ROSAT survey produced the sharpest, most sensitive image of the x-ray sky to date.

ROSAT Explores The X-Ray Sky
19.08.2000

Launched in 1990, the orbiting ROSAT observatory explored the Universe by viewing the entire sky in x-rays -- photons with about 1,000 times more energy than visible light. This ROSAT survey produced the sharpest, most sensitive image of the x-ray sky to date.

A Transit of Mercury
12.05.2016

On May 9, the diminutive disk of Mercury spent about seven and a half hours crossing in front of the Sun as viewed from the general vicinity of Earth. It was the second of 14 transits of the Solar System's innermost planet in the 21st century.

NGC 1898: Globular Cluster in the LMC
3.10.2018

Jewels don't shine this bright -- only stars do. And almost every spot in this glittering jewel-box of an image from the Hubble Space Telescope is a star. Now some stars are more red than our Sun, and some more blue -- but all of them are much farther away.

Looking Back at an Eclipsed Earth
2.01.2011

Here is what the Earth looks like during a solar eclipse. The shadow of the Moon can be seen darkening part of Earth. This shadow moved across the Earth at nearly 2000 kilometers per hour.

A Sunspot Up Close
6.11.2005

Why would a small part of the Sun appear slightly dark? Visible above is a close-up picture of a sunspot, a depression on the Sun's face that is slightly cooler and less luminous than the rest of the Sun.

A Sunspot Up Close
5.10.1998

Sometimes, small regions of the Sun appear unusually dark. Visible above is a close-up picture of a sunspot, a depression on the Sun's face that is slightly cooler and less luminous than the rest of the Sun.

APOD: 2024 March 24 Б Looking Back at an Eclipsed Earth
24.03.2024

Here is what the Earth looks like during a solar eclipse. The shadow of the Moon can be seen darkening part of Earth. This shadow moved across the Earth at nearly 2000 kilometers per hour.

Mercurys Transit: An Unusual Spot on the Sun
24.08.2014

What's that dot on the Sun? If you look closely, it is almost perfectly round. The dot is the result of an unusual type of solar eclipse that occurred in 2006. Usually it is the Earth's Moon that eclipses the Sun. This time, the planet Mercury took a turn.