X rays From HCG 62
9.03.2001

Scanning the skies for galaxies Canadian astronomer Paul Hickson and colleagues identified some 100 compact groups of galaxies, now appropriately called Hickson Compact Groups (HCGs). With only a few member galaxies per group, HCGs...

X Ray Rainbows
11.05.2001

A drop of water or prism of glass can spread out visible sunlight into a rainbow of colors. In order of increasing energy, the well known spectrum of colors in a rainbow runs red, orange, yellow, green, blue, indigo, violet.

X Ray Rainbows
28.09.2002

A drop of water or prism of glass can spread out visible sunlight into a rainbow of colors. In order of increasing energy, the well known spectrum of colors in a rainbow runs red, orange, yellow, green, blue, indigo, violet.

Recurrent Nova RS Ophiuci
24.02.2006

This pretty star field in the constellation Ophiucus is centered on a star not often seen - RS Ophiuci. In fact, early last week RS Oph suddenly became visible to the naked eye for the first time since 1985.

La Superba
18.12.2008

Y Canum Venaticorum (Y CVn) is a very rare star in planet Earth's night sky. It's also very red, exhibiting such a remarkable spectrum of light, 19th century astronomer Angelo Secchi dubbed it La Superba.

Companion of a Young, Sun-like Star Confirmed
4.07.2010

The first direct image of an extrasolar planet orbiting a star similar to our Sun has been confirmed. Located just 500 light-years away toward the constellation Scorpius, the parent star, cataloged as 1RXS J160929.1-210524, is only slightly less massive and a little cooler than the Sun.

The El Gordo Massive Galaxy Cluster
22.04.2014

It is bigger than a bread box. In fact, it is much bigger than all bread boxes put together. Galaxy cluster ACT-CL J0102-4915 is one of the largest and most massive objects known. Dubbed...

The Tarantula Nebula
26.02.2016

The Tarantula Nebula is more than a thousand light-years in diameter, a giant star forming region within nearby satellite galaxy the Large Magellanic Cloud, about 180 thousand light-years away. The largest, most violent star...

APOD: 2023 September 6 Б HESS Telescopes Explore the High Energy Sky
6.09.2023

They may look like modern mechanical dinosaurs, but they are enormous swiveling eyes that watch the sky. The High Energy Stereoscopic System (H.E.S.S.) Observatory is composed of four 12-meter reflecting-mirror telescopes surrounding a larger telescope housing a 28-meter mirror.

APOD: 2026 May 21 Б A Collision of Galaxy Clusters
21.05.2026

This big beautiful spiral shines in X-ray light. It is about 20 times larger than our Galaxy. It belongs to Abell 2029, a galaxy cluster one billion light-years away. (To see only the galaxies...