Astronomy Cast

Astronomy Cast takes a fact based journey through the cosmos as it offers listeners weekly discussions on astronomical topics ranging from planets to cosmology.

Bright summer comet 2010

C/2009 R1 McNaught is currently the brightest comet in the summer sky. After a long break due to bad weather we finally managed to catch this object in the morning dawn of June 5 in the low northeastern sky.

During this 20 minute exposure the last quarter moon was also already well above the horizon.  Currently C/2009 R1 reaches magnitude 6 and is a nice object for binoculars. If predictions are true he could get as bright as magnitude 3-4 but observations with the naked eye will be difficult because of its low altitude.

c2009r1__04-06-10_thumbThe best observing conditions will arise in the following two weeks till mid June. Mc Naught reaches its closest approach to earth on June 15. After June 22 the moon will again interfere and the angular distance to the sun is further decreasing.

The image presents a nice long plasma tail and a shorter dust tail. The plasma tail is in fact much longer. Our 14" with a focal length of 2.100 mm show only a small piece of 25 x 16 arcminutes. After the image we inspected to comet visually through the 14 inch telescope. The tail was not visible but the coma bright, round and approx. 5' in diameter.

Rob McNaught discovered the comet on September 9 with the 0.5 Uppsala Schmidt Telescope of the Siding Spring Observatory at a magnitude of 18. Siding Spring is also involved in continuous asteroid surveys.