Popular Astronomy

May 2015

During May, four section members sent in a total of 6 drawings and 5 images of deep sky objects.

Mark Beveridge, observing from Aberdeen, imaged 3 galaxies using a 100mm f9 Skywatcher telescope and a SXR-H814 camera, plus an OAG filter wheel.  Two of these galaxies are in the constellation of Draco;  NGC5907 (below left) and NGC5985 (below right).


                                                                                                                                                                                                         NGC5907 is an edge-on spiral galaxy also known as the "splinter" galaxy;  it is about 50 million light years from the Earth and is mostly composed of low metallicity dwarf stars.

  NGC5985 is one of a trio of galaxies in this image and is the right hand face-on spiral.  In the middle is elliptical galaxy NGC5982, and on the left is edge-on spiral NGC5981.  This compact group of galaxies lies about 100 light years from Earth.  NGC5985 has an active nucleus and is a Seyfert galaxy.               



Mark's third image, left, is NGC2903, a barred spiral galaxy about 30 million light years from the Earth in the constellation of Leo.  This galaxy is noted for a high rate of new star formation near the central region.  It is also emits stongly in radio frequencies, infra red, ultra violet and x-rays.                                                                                                                         

Ian Papworth, SPA Membership secretary, sent in a total of five images this month;  three of planetary nebulae and two of galaxies.  Below left is M27 the "dumbbell" in the constellation of Vulpecula.  It was the first planetary nebula to be discovered (by Charles Messier in 1764, although it was William Herschel who coined the name "planetary nebula" in the 1780's).   It is about 8 x 6 arcminutes in angular size.  Below right is M97, the "owl" planetary nebula in the constellation of Ursa Major. Discovered by another French astronomer Pierre Mechain in 1781, this object is smaller in angular size than M27 at about 3.4 arcminutes in diameter.



Ian's third planetary nebula is M57, the "ring" in the constellation of Lyra.  Frenchman Antoine Darquier de Pellepoix discovered this object in 1779.  Charles Messier also found it within days and entered it into his catalogue.  M57  is much smaller in angular size than the other two at 1.5 x 1.0 arcminutes.  




On the left is Ian's image of M66, one of three spiral galaxies that make up the Leo Triplet or M66 group:  M66, M65 and NGC3628.  M66 is about 35 million light years from the Earth, and its unusual appearance, due to a past encounter with NGC3628, gives it 16th place in Halton Arp's Atlas of Peculiar Galaxies.

   Ian's final image this month is M64, the so called "black eye"  galaxy in the constellation of Coma Berenices;  which has a very distinctive lane of dust obscuring part of the bright central region. This object is about 24 million lght years from the Earth and is classed as a Seyfert galaxy due to its active galactic nucleus.

 All of Ian's images were made using a Celestron 6 SE f 6.3 SCT and a AWO ASI 120MM camera plus colour filters.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

Dale Holt  sent in a drawing of Arp 69 (right), a face-on spiral galaxy in the constellation of Bootes.  There is a small galaxy located above the larger one, which Dale has captured in his sketch; both are about 175 million light years from the Earth so may have interacted in the past; certainly Arp 69 looks gravitationally disturbed and displays a high rate of star formation.  In the Atlas of Peculiar galaxies, the original plate does suggest that these galaxies are connected by a very tenuous extention of the larger galaxy's spiral arm.

Dale used a 505mm Newtonian telescope attached to a cooled Watec 120N+ video camera to make this sketch.


Mike Wood sent in two sketches of galaxies.   NGC4274, in the constellation of Coma Berenices, (below, left)and NGC's 4612 and 4623 in the constellation of Virgo (below, right).

NGC4274 is an almost edge-on barred lenticular galaxy, in the centre of Mike's sketch;  To the right of NGC4274 three smaller galaxies can be seen, uppermost NGC4278, middle NGC4283, and NGC 4268:  they are all members of the NGC4274 group of galaxies. 

NGC4612 (uppermost in the sketch) and NGC4623 are two lenticular (type S0) galaxies belonging to the Virgo cluster of galaxies, which may have as many as 2000 members.


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