Orion composite image captured and processed over three years at the Jodrell Plank Observatory

 

The Constellation Orion - Composite of images captured and stacked using the Altair Astro 66mm Doublet ED Refractor with a focal reducer and field flattener and the Canon 600d DSLR with a zoom lens at f=18mm. Credit: the Jodrell Plank Observatory Imaging Team 

 The northern winter constellation Orion is now a prominent feature looking south on a clear night. Alpha Orionis, otherwise known as Betelgeuse, is back to its brightest best after a recent period of dimming. Professional astronomers have decided that previous estimates of its size had been too great and now believe it to be a third of what was originally thought. If this is true, estimates of how long this red supergiant star has before it goes supernova will have to be extended.

Other features to note are:

• The bright stars that make up the constellation; Betelgeuse, Bellatrix Alnitak, Alnilam Mintaka, Saiph, and Rigel are at varying distances from the Earth. If we could view the constellation from another planet light years away elsewhere in the Milky Way, it would look quite different.
• Close to the left star in Orion's Belt, Alnitak, you can pick out the emission 'Flame Nebula'

This image of Alnitak and the Flame Nebula was taken at the Jodrell Plank Observatory using the 127mm Meade Apo Refractor.  If you look closely at Alnitak , at about 10 o' clock, you can see one of its two fourth magnitude companion stars. Alnitak is a hot blue supergiant over thirty times more massive and 21,000 times brighter than the Sun. It is estimated to be over 1000 light years distant from Earth.

• Just below Alnitak is the dark  'Horsehead Nebula' created by dust being silhouetted against an emission nebula behind it.

The Horsehead Nebula is approximately 1375 light years distant from Earth. It is quite large and seen from our perspective covers approximately 6 square light years. The Horsehead Nebula is a mixture of hydrogen gas and dust. The bright star Sigma Orionis seen to the left and below the nebula is ionizing the gas behind it and causing it to glow, the dust prevents us seeing this and creates the dark Horsehead Nebula as a darker region. The Horsehead Nebula is an active location for the formation of low mass stars. When viewed at infra-red wavelengths the Horsehead Nebula is transformed and glows. The astro-imager Robert Gendler's 'Astro Photo of the Day (APOD)' , created from data captured by large professional telescopes, is well worth a look!

Robert Gendler's Spectacular image of the Horsehead Nebula

• Barnards Loop - the arc of red luminosity that sits to the left and wraps around the three stars that make up Orion's Belt is known as Barnards Loop. The emission nebula is named after the pioneer astrophotographer E E Barnard who photographed and published it in 1894. It is an integral part of the wider Orion Molecular Cloud (OMC) Complex. The stars within the OMC are thought to be responsible for ionizing the gas in the 'Loop' and causing it to emit photons of light. The 'Loop' extends for approximately 10 arc-degrees as viewed from Earth. It is apparent in long exposure photographs but very difficult to spot with the eye even from dark sky locations. The 'Loop' is estimated to be between 440 and 520 light years distant which would imply dimensions between 1000 and 300 light years across. It is believed that the loop is the expanded shock wave from a supernova which occurred in a multiple star system some 2million years ago.

• The Orion Nebula or Messier 42 is located in Orion's Dagger an asterism which is visible to the naked eye from most suburban locations. It is a wonderful sight in binoculars or a small telescope. It is a bright concentration of ionized hydrogen gas and dust and at a distance of approximately 1345 light years is the closest location of massive star formation. Messier 42 is part of the wider Orion Nebula Complex. Messier 42 is 24 light years from side to side and has a mass equivalent to about 2000 Suns. At it's centre is a cluster of bright young and very hot blue stars known as the Trapezium. The red colours seen in the nebula are the result of ionized hydrogen gas the blue colours are created by ultra violet light from the hot young stars being reflected. 

• The Running Man Nebula or NGC 1977 is a reflection nebula located just north of Messier 42. The nebula contains the bright star cluster NGC 1981.

All the staff at the Jodrell Plank Observatory look forward to the dark winter months and in particular to the appearance of the constellation Orion striding across our southern horizon.

Our favourite view of the area around Alnitak taken with the 127mm Meade Apo refractor and Canon 600d DSLR. - Kurt Thrust current Director of the Jodrell Plank Observatory

Credit: Wikipedia