Tonight’s Sky: April 2014 (by Hubble Space Telescope)
Backyard stargazers get a monthly guide to the northern hemisphere’s skywatching events with “Tonight’s Sky.” April is a good month for eclipses. Lucky viewers will see a total lunar eclipse or a partial solar eclipse.
"Tonight’s Sky" is produced by HubbleSite.org, online home of the Hubble Space Telescope. This is a recurring show, and you can find more episodes — and other astronomy videos — at HubbleSite.org.
Visit Tonight’s Sky on HubbleSite.
ESOcast 64: First Ring System Around Asteroid (by Eso Observatory)
This ESOcast shows how observations at many sites in South America, including ESO’s La Silla Observatory, have made the surprise discovery that the remote asteroid Chariklo is surrounded by two dense and narrow rings. This is the smallest object by far found to have rings and only the fifth body in the Solar System — after the much larger planets Jupiter, Saturn, Uranus and Neptune — to have this feature. The origin of these rings remains a mystery, but they may be the result of a collision that created a disc of debris.
This video is available for download in various formats on: http://www.eso.org/public/videos/eso1…
Visual design and editing: Martin Kornmesser and Luis Calçada.
Editing: Herbert Zodet.
Web and technical support: Mathias André and Raquel Yumi Shida.
Written by: Ryan Laird and Richard Hook.
Presented by: Joe Liske (Dr. J).
Narration: Sara Mendes da Costa.
Music: John Stanford (johnstanfordmusic.com).
Footage and photos: ESO, Felipe Braga Ribas, Luis Calçada, Martin Kornmesser, José Francisco Salgado (josefrancisco.org), Alexandre Santerne, NASA, ESA and M. Showalter (SETI Institute).
Directed by: Herbert Zodet.
Executive producer: Lars Lindberg Christensen.
An international team of astronomers, led by Felipe Braga-Ribas (Observatório Nacional/MCTI, Rio de Janeiro, Brazil), has used telescopes at seven locations in South America, including the 1.54-metre Danish and TRAPPIST telescopes at ESO’s La Silla Observatory in Chile, to make a surprise discovery in the outer Solar System.
Secrets at the heart of NGC 5793
This new Hubble image is centred on NGC 5793, a spiral galaxy over 150 million light-years away in the constellation of Libra. This galaxy has two particularly striking features: a beautiful dust lane and an intensely bright centre — much brighter than that of our own galaxy, or indeed those of most spiral galaxies we observe.
NGC 5793 is a Seyfert galaxy. These galaxies have incredibly luminous centres that are thought to be caused by hungry supermassive black holes — black holes that can be billions of times the size of the Sun — that pull in and devour gas and dust from their surroundings.
This galaxy is of great interest to astronomers for many reasons. For one, it appears to house objects known as masers. Whereas lasers emit visible light, masers emit microwave radiation . Naturally occurring masers, like those observed in NGC 5793, can tell us a lot about their environment; we see these kinds of masers in areas where stars are forming. In NGC 5793 there are also intense mega-masers, which are thousands of times more luminous than the Sun.
A version of this image was submitted to the Hubble’s Hidden Treasures image processing competition by contestant Judy Schmidt.
 This name originates from the acronym Microwave Amplification by Stimulated Emission of Radiation. Maser emission is caused by particles that absorb energy from their surroundings and then re-emit this in the microwave part of the spectrum.
NASA, ESA, and E. Perlman (Florida Institute of Technology)
Acknowledgement: Judy Schmidt