Popular Astronomy

June 2016

This month, despite a shortage of clear skies and few hours of true darkness, four section members sent in 14 observations:  12 images and 2 sketches.

Ian Papworth, SPA membership secretary, sent 3 images of globular clusters:  they are (below, clockwise) NGC5466, in the constellation of Bootes, M13 in Hercules and M56 in Lyra.  NGC5466, in common with most globulars, is metal poor;  it is unusual however as it is the source of a stream of stars known as the NGC5466 stream or the 45 degree tidal stream, which is about 1.5 degrees wide and stretches from  Bootes to Ursa Major.  Ian used a Celestron Nexstar 6SE f6.3 Schmidt Cassegrain telescope and a ZWO ASI 120MM camera plus R, G and B filters.                                                                                                                                                   





In 1974 the radio dish at Arecibo, Puerto Rico aimed a message towards M13, some 25,000 light years away.  In the time it will take for the signal to arrive, the proper motion of M13 is around 24 light years, just over a quarter of its radius:  a good choice of target therefore!


                                                                                       There is a suggestion that M57, which follows a retrograde orbit around our galaxy, was once associated with a dwarf galaxy which merged with our own;  the surviving nucleus of that dwarf galaxy being Omega Centauri.

David Davies, using a variety of telescopes plus a QSI 583 camera and R, G and B filters, produced the following four images.  From the left, clockwise is NGC4565 (also in the image is NGC 4562), an edge-on spiral galaxy in the constellation of Coma Berenices;   M13 globular cluster in Hercules;  next a supernova in elliptical galaxy NGC4125 lying in Draco and finally M94, a face-on spiral galaxy in Cane Venatici.                                                                         


                                                                              The supernova, a type 1a, is just above the galactic centre.  It was discovered at the Lick Observatory on 28th May 2016, and is around apparent magnitude 14.  M94 is notable for having two rings, clearly evident in this image.  

 Michael Kinns submitted two sketches of galaxies.  Below left is M85 and NGC4394;  a lenticular (some say elliptical) and a barred spiral respectively, in the constellation of Coma Berenices - these two are interacting.  Below right is NGC4559, aka Caldwell 36, a spiral also in Coma Berenices.  Michael used an Orion Optics SPX200 f6 Newtonian reflector, at x100 magnification.



Geoff Elston, SPA Solar section director, sent in 5 images from observing sessions between February and mid June.  The first four are shown below;  from the left, globular clusters M3 in the constellation of Canes Venatici, M13 in Hercules, M13 and NGC6207 (a spiral galaxy to the left and below M13 in this image), and galaxy M100 in Coma Berenices.  Below these four is an image of NGC2158 and M35, open clusters in Gemini.  Geoff employed a Vixen 80mm refractor, and an unmodified Canon 550D DSLR (unmodified).                                                                           


In this last image, NGC2158 is the more compact open cluster to the right of M35.  M35 is about 9000 light years closer to us.  NGC2158 was once thought to be a globular cluster, but is now known to be a metal - poor open cluster, about 2 billion years old.                                                                             

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