Spring Deep Sky Objects
As Winter gives way to Spring we are no longer looking across the plane of the Milky Way so largely avoiding its spurs or arms consisting of stars, dust, and gas. We can now look out into extragalactic space, with relative clarity. This allows our more distant neighbours a chance to shine; this is Galaxy Season!
The night-time realm on display at this time of year stretches all the way from Ursa Major in the North, to Corvus the Crow in the South, taking in Canes Venatici, Leo, Virgo, Bootes, and Coma Berenices on the way.
You will need at least binoculars or a telescope to see the galaxies on show at this time of year and to see colours you will need to use photography. Looking through a moderately powered telescope we can begin to see that galaxies form clusters or are stretched out into strands.
Additionally at this time of year there are some wonderful star clusters, including the impressive Great Globular Cluster in Hercules. On a good night this may be visible to the naked eye but shows well with binoculars.
The above image has been generated using Stellarium planetarium software. Further details can be found on the Stellarium website
The galaxies of Canes Venatici
Just below the handle of the Plough is the constellation of Canes Venatici, the Hunting Dogs. This constellation is host to a number of interesting galaxies, including the Whirlpool, the Sunflower and the Croc’s Eye galaxies, as well as the unnamed M106 galaxy.
M51 The Whirlpool Galaxy
M51, a spiral galaxy disrupting its neighbour, can be easily spotted with modest equipment in Ursa Major, just below the handle of the Plough. Although quite small it is distinctive with its companion.
M51 The Whirlpool Galaxy
Image: (c) Mike Cranfield AAS (astrobin)
M63 The Sunflower Galaxy
M63 is a spiral galaxy but, although a two-armed spiral structure is evident in near infrared light, in visible light the spiral structure is rather less obvious. Spiral galaxies with this less well defined spiral structure, like M63, are known as flocculent galaxies.
M63 The Sunflower Galaxy
Image: (c) Mike Cranfield AAS (astrobin)
The galaxies of Leo, Virgo and Coma Berenices
The constellations of Leo, Virgo and Coma Berenices are host to many of the Galaxies we can see relatively easily from Earth.
In particular Virgo and Coma Berenices contain the Virgo Cluster, a group of galaxies that lies at the heart of the Virgo Supercluster. The latter includes the Local Group of galaxies to which our own Milky Way belongs.
Within the Virgo Cluster we can find a chain of bright galaxies, identified as the “Markarian Chain”. Virgo also contains the giant elliptical galaxy M87. The supermassive black hole at the centre of M87 was the first to be directly photographed.
Among the galaxies in Leo, just below the rear and East of Leo we have the Leo triplet a popular target for astronomers.
Markarian's Chain
In Virgo we can find a chain of brighter galaxies, identified as the “Markarian Chain” . Within this chain there are some groupings such as the Eyes, two interacting galaxies (just right of centre of the image), and the Cosmic or Galactic Face (on the right hand side of the image). This chain can be captured with modest equipment such as a camera on a tripod, eg with 20 or more 2 second exposures using a 200mm lens and then stacked.
Markarian’s Chain
Image: (c) Mike Cranfield AAS (astrobin)
The Leo Triplet
This small group of galaxies is located around 35 million light years from us. To the right of the image we see M65 and M66 (top and bottom right respectively in the image). On the left in the image we see the Hamburger Galaxy. The "patty" in the hamburger is in fact a broad lane of dust along the outer edge of the galaxy's spiral arms that obscures the inner part of the galaxy from our view.
The Leo Triplet
Image: (c) Mike Cranfield AAS (astrobin)
M87 Virgo A Elliptical Galaxy
M87 is a massive elliptical galaxy (it lacks the spiral structure exhibited by spiral galaxies). The supermassive black hole at its centre was the first to have been directly photographed. The galaxy is notable for the jet of plasma travelling at close to light speed and originating from the central black hole. This can be seen extending left in the image. Although the galaxy can be seen in a moderate telescope, you will need photography to see the jet.
M87 Virgo A Elliptical Galaxy
Image: (c) Mike Cranfield AAS (astrobin)
NGC4216 supernova in Virgo
This image contains three galaxies listed in John Louis Emil Dreyer's New General Catalogue (NGC) of Nebulae and Clusters of Stars published in 1888. NGC4216 is the largest of the three and was, at the time this image was captured, hosting a supernova. Although situated some 55 million light years away, this exploding star looks as bright to us as some of the stars in our own galaxy. The multitude of galaxies in this area of the sky is fertile hunting ground for transient supernovae.
NGC4216 supernova in Virgo
Image: (c) Mike Cranfield AAS (astrobin)
Star clusters
In addition to the many galaxies, the Spring night sky offers some beautiful star clusters to observe.
M3 Globular Cluster
M3 is a cluster of around 500,000 stars bound together by mutual gravitational attraction. Its brightness is just beyond the limit of naked eye visibility although in very dark skies it may be possible to make it out as a smudge. However, in a moderate sized telescope it offers a splendid sight.
M3 Globular Cluster
Image: (c) Mike Cranfield AAS (astrobin)
M13 Great Star Cluster in Hercules
M13 is a collection of several 100,000s of stars bound together by mutual gravitational attraction. In 1974 a message containing encoded data about our Earth was transmitted from the Arecibo Observatory, Puerto Rico. The cluster is 22,000 light years away, so it will take a while to get there!
M13 Great Star Cluster in Hercules
Image: (c) Mike Cranfield AAS (astrobin)
The Milky Way
As Spring turns to Summer, we get to see towards the Centre of our own Galaxy in the constellation of Sagittarius but we must be prepared to be up and in position well before dawn to see the Milky Way at its best.
Wide angle imaging of the Milky Way is possible for several seconds at a time, and it is worth trying to do so with any form of camera, especially if you can go to a relatively dark and interesting part of the South Coast at this time of Year.
Milky Way over Pulpit Rock
Images: (c) Phil Piper AAS
Milky Way over Durdel Door
Images: (c) Phil Piper AAS