Popular Astronomy

October 2016

Six section members submitted their observations this month, in total twenty five digital images.

Mark Beveridge of Aberdeen sent in seven of these.  Below left is M2, a globular cluster in the constellation of Aquarius, then in a clockwise direction, M27 the "dumbbell" planetary nebula in Vulpecula, NGC6781 planetary nebula in Aquarius and NGC7009, also a planetary nebula in Aquarius also known as the "Saturn " nebula;  which bears a resemblance to the nearly edge - on ringed planet.       

                                                                                                                                                                      Below left is an enlarged, cropped version of the NGC7009 image, then, clockwise, M57 the "ring" planetary nebula in Lyra, M74 spiral galaxy in Pisces and NGC1579 emission nebula in Perseus.  The latter is sometimes called the "Northern triffid" and is a HII region of new star formation about 2,000 light years from the Earth.  It resembles M20, the "triffid" nebula in Sagittarius, having both emission and reflection components, plus dark lanes of dust; in fact much of the visible spectrum light from the young stars is being obscured, and infra red telescopes are required to study them.  Mark used a 140mm f14.3 Maksutov-Cassegrain telescope and SXR-H814 camera plus R, G and B filters.


Geoff Elston, SPA Solar section Director, also sent in seven images taken via an 80mm refractor and Canon D550 DSLR camera.  The first two below are the planeary nebulae M27 and M57 also seen above;  it is interesting to note the kind of image each telescope/camera combination can produce.

  Geoff's next four images are, clockwise from the left below, M31 spiral galaxy in the constellation of Andromeda, M39 open cluster in Cygnus, NGC6910 the "rocking horse" open cluster also in Cygnus and globular cluster NGC6934 in Delphinus.                      


                                                                                                                                                    Geoff's final image (left) is of NGC6960, the western part of the Veil supernova remnant in Cygnus.  Estimates of the age of this object vary widely between 5,000 and 8,000 years.  It is around 1,500 light years from the Earth.  The whole remnant covers an area of around three degrees, or six times the diameter of the full moon.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          


Ian Sharp imaged edge - on galaxy NGC891 (right) in  the constellation of Andromeda.  It is a member of the NGC1023 group of galaxies and is around 30 million light years from the Earth.  It is thought that our own galaxy the Milky Way would look very much like NGC891 if it were possible to view it edge-on from a great distance.  Ian used a 250mm Schmidt Cassegrain telescope and an Atik infinity one-shot colour camera to capture this image.

Dave Hancox of Dalmellinton imaged three emission nebulae with a 102mm triplet refractor and a QHY 8L camera. On the left is IC396, the "elephant's trunk" nebula in the constellation of Cepheus.  Below it is NGC6888, the "crescent" nebula and to the right NGC7000, the "North America" nebula;  both of these in Cygnus.     


  The "crescent" is unlike the others, because it is the stellar wind from a Wolf Rayet star that is causing the gas it expelled when it was in the red giant stage to become ionised.  On the other hand, it is young, hot stars producing the ionisation in the gas and dust clouds from which they were formed in IC396 and NGC7000.  In both cases, it is when ionised hydrogen, (HII), recombines with an electron and then emits a photon of wavelenth 656.3 nanometers, that the charactristic pink/red glow is produced.

Steve Norrie of Fife sent in five images;  below left is emission/dark nebula IC434 the "horsehead" in the constellation of Orion and to the right is IC5070 the "pelican" emission nebula in Cygnus.



                                                                                                                                                                                    Steve's next three images are, clockwise from below left, M1 the "crab" supernova remnant in Taurus, M81 "Bode's galaxy" in Ursa Major, and M74 galaxy in Pisces.  



M74, featured twice in this report, is about 32 light years from the Earth.  Face-on, and with a low surface brightness, this magnitude 10 galaxy can be hard to see in the eyepiece of a telescope regardless of aperture.  Supernovae have been seen in M74 in 2002, 2003 and 2013.  The 2002 event was a rare type 1c which means the progenitor star possessed almost no hydrogen and little helium.  This corresponds to a type of Wolf Rayet star, probably with an initial mass of more than nine times that of the sun.  Steve used a 127mm f5 refractor and an Atik 490 EX one-shot colour camera for these images.

David Davies of Cambridge sent in two images.  Below left is the "Deer Lick" group of galaxies, most prominent of which is NGC7331, in the constellation of Pegasus.  Right is Hickson 92, better known as "Stephan's quintet", also in Pegasus.  David secured these images via a 200mm Richey Chretien telescope and a QSI583 camera plus R,G and B filters.

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