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Popular Astronomy

April 2014

This month, member Mark Beveridge, who lives in Aberdeen, sent in a CD containing 35 superb deep sky images, taken between the 8th of September 2013 and the 20th of March 2014. 

With the exception of the last date, all of the images were taken via an 80mm Skywatcher f7.5 refractor.  The two images from 20th March were taken using a 100mm Skywatcher refractor.  Both telescopes were guided by an 80mm guide scope and a Superstar mono guide camera, and were carried by an HEQ 5 pro mount.  Mark uses an SXR-H9c colour camera, and processes the images in Astroart 5.

A sample of Mark's imaging prowess is shown below:-


This first image is of globular cluster M13 in the constellation of Hercules, a favourite target for amateur astronomers.

Much less easy to see is magnitude 12 spiral galaxy NGC6207, at the extreme top left in this image.  It is 30 million light years distant, about 1200 times the distance of M13!                                                                                                                 

                                                                                                                

                                                                                                                 

 

   


The image on the right is of IC1470, a 3 arcminute emission nebula in the constellation of Cepheus.  Strong Hydrogen alpha emission gives rise to the predominant red/pink in true colour images. 

The image below is IC1805, another emission nebula, in the constellation of Cassiopeia.  Called the "Heart" nebula, it is about 7500 light years from Earth, in the Perseus arm of the galaxy.  It owes its shape and colour to intense radiation from the open cluster, Melotte 15, which you can see at the centre of the nebulosity.  Some of these stars are about 50 solar masses. The whole nebula is about 1 x 1 degrees in angular dimensions.

                                                                                                                  


    

Below left is  IC5070, the Pelican nebula, a much imaged emission nebula in the constellation of Cygnus, near Deneb.  It is separated from another famous structure, the North American nebula, by a dark dusty lane.  The Pelican nebula is an active region of star formation, and the young energetic stars are heating and ionizing the gas clouds.

Below right is the Sword Handle in the constellation of Perseus, otherwise known as NGC 884 and NGC 869.


 NGC 2403, below left, is a spiral galaxy to be found in the constellation of Camelopardis.  At around 8 million light years from Earth, it was discovered by William Herschel in 1788, and resembles M33 in appearance.   

Below right is Mark's image of the Wizard nebula NGC7380, which was discovered by Caroline Herschel in 1787.  It is located in the constellation of Cepheus, at 8000 light years from the earth and is about 100 light years in extent.  Radiation from the young stars in the open cluster at the heart of the nebula is energising and sculpting the gas cloud.

                                                                                                            

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          


  

Here on the left is spiral galaxy NGC6946.  In the constellation of Cepheus, this face - on spiral was discovered by William Herschel in 1798 and holds the record for the number of supernovae discoveries - nine between 1917 and 2008.  It lies close to the galactic plane of the Milky Way, and is quite hard to see in the eyepiece of any telescope, due to the obscuring effect of galactic dust.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                         

The image on the right is of NGC 281, also known as the Pacman Nebula, which lies in the constellation of  Cassiopeia.  It was discovered in 1883 by E.E.Barnard.  This is a star - forming nebula, and the cluster of young stars within it as called IC 1590.  At about 9000 light years from Earth, it lies above the galactic plane, giving astronomers a clear view of these young, massive stars.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         


The image below is of spiral galaxy M33, in the constellation of Triangulum.  It is the third largest in the local group of galxies, after M31 in Andromeda and our own Milky Way.  At 2.4 million light years from Earth, it  has an angular size of 67 x 42 arcminutes, and just fits onto the camera chip, for Mark's particular telecope/camera combination.                         

     


M42 and M43, the Orion Nebula, and its smaller neighbour De Mairan's Nebula are parts of the much larger Orion Molecular cloud complex.  

M42 is a naked eye object, and has been estimated to be about 24 light years across.

A sheer visual delight for beginners in astronomy, capturing the faint outer detail without losing the essence of the bright open cluster known as the trapezium is a perennial challenge for seasoned imagers.

                                                                                                                                                                                                                                                                                                                                                        

To the right is Mark's image of Messier 1, the Crab Nebula, which is in the constellation of Taurus.  It is the brightest supernova remnant, and may be seen in binoculars on a dark, clear night about 1 degree North West of Tau Tauri.  M1 is 6500 light years from Earth, and is about 10 light years across.

The supernova that created this remnant took place in 1054, and was observed and recorded by Chinese astronomers.  It is magnitude 8.4 today, but may have been as bright as mgnitude -5 in 1054 and would have been visible during daylight for many days.  Situated in the Perseus arm of the Galaxy, the neutron star ("pulsar") at the centre of the nebula spins at about 30 times per second, and emits pulses of electromagnetic radiation across abroad spectrum of frequencies from gamma rays to radio waves.                                                                                                                                                                                                                                             


   On the left is an image of the Horsehead Nebula, technically dark nebula Barnard 33 within the emission nebula IC 434, in the constellation of Orion. 

It is about 1500 light years from Earth.  The Horsehead shape is visible as thick dust is backlit by red/pink glowing hydrogen, ionised by the star sigma Orionis ( just out of the bottom centre of this image but its glow can clearly be seen)    

This nebula is part of the much bigger Orion molecular cloud complex.

A firm favourite with imagers, it is much more difficult to see through the eyepiece, many astronomers saying that a minimum of 200mm aperture plus a  Hydrogen - Beta filter are required.    



                              

                                                                                                                                                                                                                                                                                                                                                                             Above are Mark's images of spiral galaxy M51, using an 80mm telescope on the left, and a 100mm on the right.  Similarly, below, are two views of M101 taken with the two telescopes:

                                                               


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