Winter highlights

Winter Deep Sky Objects

Many objects we can see in Autumn, will still be with us in Winter, just arriving earlier and setting earlier. Even the Pleiades and other objects are visible early in the evening before the days lengthen. In addition, we now get introduced to new deep sky objects that range from the constellations of Leo, Cancer, Gemini and Monceros.

Orion is a constellation that is rich in interesting deep sky objects and it is present in both the Autumn and Winter night skies. We will start our exploration of the Winter night sky with this constellation.

The above image has been generated using Stellarium planetarium software. Further details can be found on the Stellarium website

Orion

Orion is visible in Autumn and Winter and we included the Great Orion Nebula in our Autumn roundup. Orion is embedded in a huge molecular cloud or spur attached to one of the Milky Way’s arms and is home to many other interesting objects. These include M78 Casper the Friendly Ghost, the Flame and Horsehead nebulae, the Witches Head Nebula, and Barnard’s loop. 

The Flame and Horsehead Nebulae

It is relatively easy to spot the Flame Nebula (shown at the top of this image) with a pair of Binoculars or a small telescope,The Horse head itself, on the other hand, is much harder to see as the curtain behind it, composed of ionised Hydrogen, is quite dim. It responds to use of an infra red sensitive camera or night vision equipment. The horse head itself is part of a bank of dust.

The Flame and Horsehead Nebulae
Image: (c) Terry Tucker AAS

Casper the Friendly Ghost M78

M78, known as the Casper the Friendly Ghost Nebula, is situated above the left hand star of Orion's Belt in the direction of the red supergiant star Betelgeuse. It can be easily seen in a small telescope. Unlike the nearby Flame nebula which shines due to energetic emissions from ionised gas, the dust that forms M78 shines by reflected light from local bright stars.

M78 Casper the Friendly Ghost
Image: (c) Mike Cranfield AAS (astrobin)

Monoceros

Moving East from Orion we arrive at the constellation of Monoceros home to the Rosette Nebula and the seasonal Christmas Tree cluster.

Rosette Nebula

The stars at the centre, called the Satellite Cluster, can be seen by some people with their naked eyes under good conditions, but the cluster is easily revealed with binoculars or a small telescope. However, again, photography helps to see the nebulosity as these young bright stars expel the gas at the centre with their solar winds, ionising the hydrogen with their radiation and making the expelled gas glow red. Increasingly more modern mobile phones can capture the nebulosity.

The Rosette Nebula and Satellite Cluster
Image: (c) Terry Tucker AAS

Christmas Tree Cluster and Cone Nebula

Close to the Rosette Nebula we have this seasonal deep sky object. This image was taken using filters to capture specific wavelengths of light which have then been combined to create the image. The technique is similar to that used by the Hubble Space Telescope. The orange areas show areas of ionised hydrogen. The Teal areas show areas where there are emissions from doubly ionised Oxygen. The lighter blue is an area where the bright stars are reflecting light off the surrounding dust. You can see the star cluster here forms a distinctive Christmas Tree shape with its apex close to the dark nebulosity forming the Cone Nebula, which looks like an angel on top of the tree!

The Christmas Tree Cluster and Cone Nebula
Image: (c) Mike Cranfield AAS (astrobin)

Assorted star clusters

We could endlessly continue to find nebulae to look at in this area, like the Jellyfish Nebula or the Monkey’s Head nebula in Gemini, or the Seagull nebula near Sirius, but they are difficult to see especially in Bortle 3 or 4 skies, (1 being the best). However, get relatively low power binoculars and some wonderful star clusters come into view.

Below is another screen shot from Stellarium. Notice that the thinning Milky Way passes through this area, but if you can actually see it you have exceptional skies, and it makes it easier to see all of these clusters, marked as rings of yellow beads.

The above image has been generated using Stellarium planetarium software. Further details can be found on the Stellarium website

In Winter the rotating star field allows us to view through the edge of the Milky Way. In this area of the sky we begin to see lots of clusters of stars.

It is not possible to list them all here, but M44, known as the Beehive Cluster, in the centre of Cancer is one of the standout ones. It seems just like  a bunch of insects buzzing around a central point. It is also a cluster where it is easier to pick out colours of stars visually with optical enhancement.

The Shoe Buckle Cluster in Gemini has the Jellyfish and Monkey’s head nebulae nearby.

Many of the brighter clusters already mentioned are shown here, as well as many more of medium brightness worth investigating. All are easily visible with binoculars, or even photographed with a few second exposures with ISOs of 400 and above, or using a low light/night/dusk setting on a mobile phone.

Also modern mobile phones are becoming more able to capture the objects we mentioned in groups of 2 or 3, especially the clusters, which litter the sky here.

It is worth experimenting with a firm support and different focal lengths and exposure times to get the best views of clusters or groups of clusters. Most problems with seeing or imaging clusters is down to a lack of transparency, caused by thin cloud, high atmospheric winds or light pollution.

The Beehive Cluster M44

Over time the solar wind from star clusters will dispel the giant molecular clouds from which they were formed. The star cluster will move through the galaxy loosely bound by mutual gravitational attraction. M44, imaged here, is an example of this in the constellation of Cancer. A number of the brighter stars trace out the shape of a traditional skep beehive (in the centre of this image) which gives the cluster its popular name. The cluster is visible to the naked eye as a fuzzy object under dark skies. With optical enhancement you can start to pick out some different star colours.

The Beehive Cluster M44
Image: (c) Mike Cranfield AAS (astrobin)