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Popular Astronomy

December 2016

During December, four section members were able to observe deep sky objects, producing three sketches and twenty three images.

Michael Kinns, observing from Eastry, used an Orion 200mm f6 Newtonian reflector to make the three sketches. all of open clusters.  Below left is NGC654 in the constellation of Cassiopeia at a magnification of 150x.  To the right is NGC7789 also in Cassiopeia (75x) and below that NGC6940 in Vulpecula (67x).

                                                                                

NGC654 surrounds a magnitude 7 supergiant, which may indeed be within it and not a foreground star;  and is a young cluster at an estimated age of 15 to 40 million years old, containing about 80 stars, a few of which are luminous type B.

We think that NGC654 belongs to the stellar association Cassiopeia OB8 in the Perseus arm of the milky way, as well as open clusters NGC663, 659 and M103, which are of a similar age and are all around 7,800 light years from the Earth.

  

David Davis, observing from Cambridge, sent in four images.  Below, clockwise from the left are M34 open cluster in the constellation of Perseus, M36 open cluster in Auriga, NGC7635 the "bubble" emission nebula in Cassiopeia and the same nebula but this time taken with narrow band filters to produce the familiar "Hubble Palette".   David used an 8" Richey Chretien telescope and a QSI 583 mono camera plus red, green, blue, SII, H alpha and OIII filters for these images.                                                                                        

                                                                                                                                                              The "bubble" nebula, also known as Caldwell 11 or Sharpless 162, was imaged in 2016 by the Hubble Space Telescope to mark the 26th anniversary of its launch.  The nebula is about 7,000 light years from the Earth and is around 7 light years in diameter;  a hot O type star about 45 times the mass of the sun and many hundreds of thousands of times brighter is creating a cavity in the surrounding molecular cloud of gas and dust by way of its intense radiation and stellar wind.                                        

Steve Norrie of Fife sent in ten images of a variety of deep sky objects.  Clockwise from below left are IC105, the "flaming star" emission/reflection nebula in the constellation of Auriga, IC410 also in Auriga, M31 spiral galaxy in Andromeda and M38 open cluster in Auriga.                                    

                                                                                 

         

Steve's next four images are, from below left, reflection nebula M78 in the constellation of Orion, (also imaged by Mark Beveridge, see below), planetary nebula M97 (the "owl") in Ursa Major, emission nebula NGC1499 (the "California" nebula) in Perseus and NGC1973, the "running man" , another reflection nebula in Orion.  

                                                                                                                                                                                                                                                            Steve also imaged globular cluster NGC2419 in the constellation of Lynx, below left, and to the right, and face on spiral galaxy M74 in Pisces.  NGC2419 is magnitude 9, not surprising since it is an estimated 300,000 light years from the Earth:  American astronomer Harlow Shapley called it the "intergalactic tramp" because he thought it was escaping the milky way for intergalactic space.  We now know it is in an orbit around the centre of the milky way such that it takes 3 billion years or so to complete a single orbit.  Steve used an ES 127mm f5 APO refractor and an Atik 920 EX colour camera.                                                                                    

    Mark Beveridge, observing from Thainstone, near Inverurie, used a 140mm f14.3 Maksutov Cassegrain telescope and a SXR-H814 mono camera plus red, green and blue filters to take nine images of deep sky objects.  The first four are, from below left, M1, the "crab" supernova remnant in the constellation of Taurus, M42 and M43 emission nebulae in Orion, M96 intermediate spiral galaxy in Leo and NGC660 galaxy in Pisces.  NGC660 is a the only known polar - ring galaxy to also be a late - type lenticular galaxy.  It may have been formed when two galaxies merged around a billion years ago.  This galaxy had an outburst in 2012 around 10 times as bright as a supernova , possibly a jet from the supermassive black hole residing at the centre.                                                                                                                   

    Mark's next four images are, from the left, below, NGC772 spiral galaxy in the constellation of Aries, NGC1073 barred spiral galaxy in Cetus, NGC2024 the "flame"emission nebula in Orion and M78 reflection nebula also in Orion  (also imaged by Steve Norrie - see above).  

      Mark's final image is NGC2174, the "monkey" emission nebula in the constellation of Orion.

Associated with open cluster NGC2175, this nebula is an active star forming region, and infra red images taken with the Hubble space telescope show structures similar to the "pillars of creation" image of the Eagle nebula in the constellation of Serpens taken in 1995.             

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