Popular Astronomy

September 2014

Dale Holt sent in this drawing of NGC6426, a globular cluster in the constellation of Ophiucus, home to many globulars much brighter than this one - described as one of the most metal - poor globulars in our Galaxies halo.  It is magnitude 10.9, and its distance from our sun is given as about 67,000 light years. It has an angular size of 3.2 arcminutes, and probably would need at least a 6" relescope to see it.                        






Alan Clitherow, Planetary Section Director, imaged the Heart Nebula, IC1805, in the constellation of Cassiopeia.  For this image Alan used a Canon EOS1100D astro - modified DSLR camera and a Sigma70 - zoom lens at f5.6.

This emission nebula is about 7,500 light years from earth, and is within the Perseus arm of the Galaxy.  The open cluster of stars at the centre of the brightest part is called Melotte 15.  There are stars here of around 50 solar masses, and it is the intense radiation from these relatively young hot stars that ionises the surrounding hydrogen gas, which emits light as the characteristic pink/red glow seen here.

Note the Perseus double cluster of stars at the top right corner.                                                                                                                       



  Solar Section Director Geoff Elston was on holiday in Northumberland during August, and packed a 10" f6.3 Meade SCT OTA, Skywatcher NEQ6 mount and a host of other equipment to enable him to take a number of deep sky images from this dark sky location.  Two of these are shown here, there should be even more to report in October.

On the left is M81, often called Bode's Galaxy after its discoverer.  This is a 10 minute exposure using a Canon D550 camera through the telescope.  On the right is a wide angle image of the Summer Triangle taken with the camera and an 18-55mm zoom lens mounted on the NEQ6 with a 5 minute exposure.  The ISO setting for both was 1800.











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