Dusty detail in elliptical galaxy NGC 2768: The  soft glow in the picture above is NGC 2768, an elliptical galaxy  located in the northern constellation of Ursa Major (The Great Bear). It  appears here as a bright oval on the sky, surrounded by a  wide, fuzzy cloud of material. This image, taken by the NASA/ESA Hubble  Space Telescope, shows the dusty structure encircling the centre of the  galaxy, forming a knotted ring around the galaxy’s brightly  glowing middle. Interestingly, this ring lies perpendicular to the plane  of NGC 2768 itself, stretching up and out of the galaxy. The dust in NGC  2768 forms an intricate network  of knots and filaments. In the centre of the galaxy are  two tiny, S-shaped symmetric jets. These two flows of material travel  outwards from the galactic centre along curved paths, and are masked by the tangle of dark dust lanes that spans the body of the  galaxy. These  jets are a sign of a very active centre. NGC 2768 is an example of a  Seyfert galaxy, an object with a supermassive black hole at its centre.  This speeds up and sucks in gas from the nearby space, creating a stream  of material swirling inwards towards the black hole known as an  accretion disc. This disk throws off material in very energetic  outbursts, creating structures like the jets seen in the image above. A  version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Judy Schmidt. One of her  images, of newborn star XZ Tauri, was awarded third prize.

Name: NGC 2768
Type: Local Universe : Galaxy : Type : EllipticalLocal Universe : Galaxy : Activity : AGN : Seyfert
Category: Galaxies
Constellation: Ursa Major
Distance: 65 million light years
Release date: 8 April 2013, 10:00
Credit: ESA/Hubble & NASAAcknowledgment: Judy Schmidt

A unique cluster: one of the hidden 15: Globular  clusters are relatively common in our sky, and generally look similar.  However, this image, taken using the NASA/ESA Hubble Space Telescope,  shows a unique example of such a cluster — Palomar 2. Palomar  2 is part of a group of 15 globulars known as the Palomar clusters.  These clusters, as the name suggests, were discovered in survey plates  from the first Palomar Observatory Sky Survey in the 1950s, a project  that involved some of the most well-known astronomers of the day,  including Edwin Hubble. They were discovered quite late because they are  so faint — each is either extremely remote, very heavily hidden behind  blankets of dust, or has a very small number of remaining stars. This  particular cluster is unique in more than one way. For one, it is the  only globular cluster that we see in this part of the sky, the northern  constellation of Auriga (The Charioteer). Globular clusters orbit the  centre of a galaxy like the Milky Way in the same way that satellites  circle around the Earth. This means that they normally lie closer in to  the galactic centre than we do, and so we almost always see them in the  same region of the sky. Palomar 2 is an exception to this, as it is  around five times further away from the centre of the Milky Way than  other clusters. It also lies in the opposite direction — further out  than Earth — and so it is classed as an “outer halo” globular. It  is also unusual due to its brightness. The cluster is veiled by a mask  of dust, dampening the apparent brightness of the stars within it and  making it appear as a very faint burst of stars. The  stunning NASA/ESA Hubble Space Telescope image above shows Palomar 2 in a  way that could not be captured from smaller or ground-based telescopes —  some amateur astronomers with large telescopes attempt to observe all of the obscure and  well-hidden Palomar 15 as a challenge, to see how many they can pick out  from the starry sky.

Name: Palomar 2
Type: Milky Way : Star : Grouping : Cluster : Globular
Category: Star Clusters
Constellation: Auriga
Release date: 15 April 2013, 10:00
Credit: ESA/Hubble & NASA

A changing fan: The Universe is rarely static, although the timescales involved can be very long. Since modern astronomical observations began we have been observing the birthplaces of new stars and planets, searching for and studying the subtle changes that help us to figure out what is happening within. The bright spot located at the edge of the bluish fan-shaped structure in this Hubble image is a young star called V* PV Cephei, or PV Cep. It is a favourite target for amateur astronomers because the fan-shaped nebulosity, known as GM 1-29 or Gyulbudaghian’s Nebula, changes over a timescale of months. The brightness of the star has also varied over time. Images of PV Cep taken in 1952 showed a nebulous streak, similar to a comet’s tail. However, these had vanished when new images of the star were obtained some twenty-five years later. Instead, the blue fan-shaped nebula had appeared. Twenty-five years is a very short period on cosmic timescales, so astronomers think that the mysterious streak may have been a temporary phenomenon, such as the remnants of a massive stellar flare — similar to the solar flares we are used to seeing in the Solar System. At the same time as this was happening, the star itself was brightening. This provided the light to illuminate the newly formed fan-shaped nebula. This brightening might be related to the start of the hydrogen-burning phase of the star, which would mean that it was reaching maturity. PV Cep is thought to be surrounded by a disc of gas and dust, which would stop light from escaping in all directions. The fan-like appearance is therefore probably a result of starlight escaping from the dust disc and projecting onto the nebula. PV Cep is located in the northern constellation of Cepheus at a distance of over 1600 light-years from Earth. A version of this image was entered into the Hubble’s Hidden Treasures competition by contestant Alexey Romashin.

Name: GM 1-29, Gyulbudaghian’s Nebula, PV Cephei
Type: Milky Way : Star : Evolutionary Stage : Young Stellar Object
Category: Nebulae
Constellation: Cepheus
Distance: 1600 light years
Release date: 22 April 2013, 10:00
Credit: ESA/Hubble & NASA.Acknowledgement: Alexey Romashin

The remains of a star gone supernova: These delicate wisps of gas make up an object known as SNR B0519-69.0, or SNR 0519 for short. The thin, blood-red shells are actually the remnants from when an unstable progenitor star exploded violently as a supernova around 600 years ago. There are several types of supernova, but for SNR 0519 the star that exploded is known to have been a white dwarf star — a Sun-like star in the final stages of its life. SNR 0519 is located over 150 000 light-years from Earth in the southern constellation of Dorado (The Dolphinfish), a constellation that also contains most of our neighbouring galaxy the Large Magellanic Cloud (LMC). Because of this, this region of the sky is full of intriguing and beautiful deep sky objects. The LMC orbits the Milky Way galaxy as a satellite and is the fourth largest in our group of galaxies, the Local Group. SNR 0519 is not alone in the LMC; the NASA/ESA Hubble Space Telescope also came across a similar bauble a few years ago in SNR B0509-67.5, a supernova of the same type as SNR 0519 with a strikingly similar appearance. A version of this image was submitted to the Hubble’s Hidden Treasures Image Processing Competition by Claude Cornen, and won sixth prize.

Name: SNR B0519-69.0
Type: Local Universe : Nebula : Type : Supernova Remnant
Category: Nebulae
Constellation: Dorado
Distance: 150000 light years
Release date: 29 April 2013, 10:00
Credit: ESA/Hubble & NASA. Acknowledgement: Claude Cornen