A galactic disc, edge-on and up close: This image snapped by the NASA/ESA Hubble Space Telescope reveals an exquisitely detailed view of part of the disc of the spiral galaxy NGC 4565. This bright galaxy is one of the most famous examples of an edge-on spiral galaxy, oriented perpendicularly to our line of sight so that we see right into its luminous disc. NGC 4565 has been nicknamed the Needle Galaxy because, when seen in full, it appears as a very narrow streak of light on the sky. The edgewise view into the Needle Galaxy shown here looks very similar to the view we have from our Solar System into the core of the Milky Way. In both cases ribbons of dust block some of the light coming from the galactic disc. To the lower right, the dust stands in even starker contrast against the copious yellow light from the star-filled central regions. NGC 4565’s core is off camera to the lower right. For a full view of NGC 4565 for comparison’s sake, see this wider field of view from ESO’s Very Large Telescope. Studying galaxies like NGC 4565 helps astronomers learn more about our home, the Milky Way. At a distance of only about 40 million light-years, NGC 4565 is relatively close by, and being seen edge-on makes it a particularly useful object for comparative study. As spiral galaxies go, NGC 4565 is a whopper — about a third as big again as the Milky Way. The image was taken with Hubble’s Advanced Camera for Surveys and has a field of view of approximately 3.4 by 3.4 arcminutes. A version of this image was entered into the Hubble’s Hidden Treasures Image Processing Competition by  contestant Josh Barrington. Hidden Treasures is an initiative to invite  astronomy enthusiasts to search the Hubble archive for stunning images  that have never been seen by the general public. The competition has now  closed and the results will be published soon.

Name: NGC 4565
Type: Local Universe : Galaxy : Type : Spiral
Category: Galaxies
Constellation: Coma Berenices
Distance: 40 million light years
Release date: 9 July 2012, 10:00
Credit: ESA/Hubble & NASA

An audience of stellar flashbulbs: The NASA/ESA Hubble Space Telescope has captured a crowd of stars that looks rather like a stadium darkened before a show, lit only by the flashbulbs of the audience’s cameras. Yet the many stars of this object, known as Messier 107, are not a fleeting phenomenon, at least by human reckoning of time — these ancient stars have gleamed for many billions of years. Messier 107 is one of more than 150 globular star clusters found around the disc of the Milky Way galaxy. These spherical collections each contain hundreds of thousands of extremely old stars and are among the oldest objects in the Milky Way. The origin of globular clusters and their impact on galactic evolution remains somewhat unclear, so astronomers continue to study them through pictures such as this one obtained by Hubble. As globular clusters go, Messier 107 is not particularly dense. Visually comparing its appearance to other globular clusters, such as Messier 53 or Messier 54 reveals that the stars within Messier 107 are not packed as tightly, thereby making its members more distinct like individual fans in a stadium's stands. Messier 107 can be found in the constellation of Ophiuchus (The Serpent Bearer) and is located about 20 000 light-years from the Solar System. French astronomer Pierre Méchain first noted the object in 1782, and British astronomer William Herschel documented it independently a year later. A Canadian astronomer, Helen Sawyer Hogg, added Messier 107 to Charles Messier's famous astronomical catalogue in 1947. This picture was obtained with the Wide Field Camera of Hubble’s Advanced Camera for Surveys. The field of view is approximately 3.4 by 3.4 arcminutes.

Name: M 107
Type: Milky Way : Star : Grouping : Cluster : Globular
Category: Star Clusters
Constellation: Ophiuchus
Distance: 20000 light years
Release date: 16 July 2012, 10:00
Credit: ESA/Hubble & NASA

A galaxy festooned with stellar nurseries: The  galaxy NGC 4700 bears the signs of the vigorous birth of many new stars  in this image captured by the NASA/ESA Hubble Space Telescope. The  many bright, pinkish clouds in NGC 4700 are known as H II regions,  where intense ultraviolet light from hot young stars is causing nearby  hydrogen gas to glow. H II regions often come part-and-parcel with the  vast molecular clouds that spawn fresh stars, thus giving rise to the  locally ionised gas. In  1610, French astronomer Nicolas-Claude Fabri de Peiresc peered through a  telescope and found what turned out to be the first H II region on  record: the Orion Nebula, located relatively close to our Solar System  here in the Milky Way. Astronomers study these regions throughout the  Milky Way and those easily seen in other galaxies to gauge the chemical  makeup of cosmic environments and their influence on the formation of  stars. NGC  4700 was discovered back in March 1786 by the British astronomer  William Herschel who noted it as a “very faint nebula”. NGC 4700, along  with many other relatively close galaxies, is found in the constellation  of Virgo (The Virgin) and is classified as a barred spiral galaxy,  similar in structure to the Milky Way. It lies about 50 million  light-years from us and is moving away from us at about 1400 km/second  due to the expansion of the Universe.

Name: NGC 4700
Type: Local Universe : Galaxy
Category: Galaxies
Constellation: Virgo
Distance: 50 million light years
Release date: 23 July 2012, 10:00
Credit: ESA/Hubble & NASA

A ten billion year stellar dance: The NASA/ESA Hubble Space Telescope offers this delightful view of the crowded stellar encampment called Messier 68, a spherical, star-filled region of space known as a globular cluster. Mutual gravitational attraction amongst a cluster’s hundreds of thousands or even millions of stars keeps stellar members in check, allowing globular clusters to hang together for many billions of years. Astronomers can measure the ages of globular clusters by looking at the light of their constituent stars. The chemical elements leave signatures in this light, and the starlight reveals that globular clusters' stars typically contain fewer heavy elements, such as carbon, oxygen and iron, than stars like the Sun. Since successive generations of stars gradually create these elements through nuclear fusion, stars having fewer of them are relics of earlier epochs in the Universe. Indeed, the stars in globular clusters rank among the oldest on record, dating back more than 10 billion years. More than 150 of these objects surround our Milky Way galaxy. On a galactic scale, globular clusters are indeed not all that big. In Messier 68's case, its constituent stars span a volume of space with a diameter of little more than a hundred light-years. The disc of the Milky Way, on the other hand, extends over some 100 000 light-years or more. Messier 68 is located about 33 000 light-years from Earth in the constellation Hydra (The Female Water Snake). French astronomer Charles Messier notched the object as the sixty-eighth entry in his famous catalogue in 1780. Hubble added Messier 68 to its own impressive list of cosmic targets in this image using the Wide Field Camera of Hubble’s Advanced Camera for Surveys. The image, which combines visible and infrared light, has a field of view of approximately 3.4 by 3.4 arcminutes.

Name: M 68
Type: Milky Way : Star : Grouping : Cluster : Globular
Category: Star Clusters
Constellation: Hydra
Distance: 35000 light years
Release date: 30 July 2012, 10:00
Credit: ESA/Hubble & NASA