Comet 81/P WIld
Comet 81/P Wild

Comet Wild 2 is a short periodic comet with an orbital period of 6 years. Before its close encounter with Jupiter during September 1974 his orbit was almost circular and had a 43 year period. But the gravitational pull of the giant gas planet made Wild 2 to a member of the inner solar system. In 2004 the comet was target of the NASA mission "Stardust", which took samples of the coma and returned them back to earth. Our image was obtained during a trip to southern france in February 2010 and shows a nice 1 degree long tail.


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.

2012 LZ1 - a big chunk of rock

Finally on Sunday, June 17, 2012, after a long period of unstable weather, I loaded my target list of minor planet followup observations for an unattended imaging run. The list contained two recently discovered NEOS: 2012 LD1 and 2012 LT7, PHA 2004 CL which was only seen for two nights in that opposition at that time, NEO 2012 BC20 deep in a crowded milkyway starfield, and numbered NEO (317685). The run was supposed to start at 21:30 UT. I was a little ahead of time. Flatfield and bias images ready, initial focus done. At 21:05 UT it was not dark enough for those faint objects. So I decided to take a shot on PHA 2012 LZ1 which was discovered on June 10 and passed the earth on June 14 in 14.5 LD (lunar distances). Only a couple of days after closest encounter this object was fairly bright with a magnitude of 15.0 but still pretty fast with an angular speed of about 30 arcseconds per minute. With an exposure time of 3-5 seconds it sould be possible to make it visible on a single exposure but preventing the object from trailing. The pointing of the telescope was a matter of a minute and a sequence of 80 images was taken from 21:15 - 21:24 UT.

First the size of 2012 LZ1 was thought to be around 500 meters according to its brightness and distance. Because of its size and proximity to the earth this object was selected as radar target for the famous Arecibo radio telescope in Puerto Rico and the results where a bit surprising: 2012 LZ1 is almost twice as big. Scientists where able to determine that this space rock was only reflecting 2-4 percent of the sunlight that hit its surface. A surface as dark as coal.

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. 

Comet C/2009 K5 (McNaught)

April 17 was a beautiful day with absolutely no clouds. The daytime sky was blue maybe a little haze was noticeable but not realy sure if that was caused by the volcanic ash coming from islandic volcano Eyjafjallajok├╝ll.

c2009k5_c14_100417_thumbAfter sunset the crescent Moon and Venus were a fine sight to see. The first half of the night was dedicated to follow-up work of NEOS K10F81A, K10G07S, K10G24A, K10G30H. For a closer at 3 am I decided to take a peak on Comet McNaught. With a brightness of 9 mag it was moving fast through the rich starfields of the milkyway. A single 30 second exposure showed a 5' large coma and a approx. 9' long tail in PA 120┬░. So McNaught is heading now to its perihel on April 30. For an animation showing the movement between the stars from 01:03 - 1:26 UT click here. ( 4 MB large)
Comet P/2010 H2

Comet P/2010 H2 is a somewhat mysterious object. It first appeared on the NEOCP on April 16 as an unusually bright 12 mag discovery with the preliminary designation 04F0011 submitted by the Crni Vrh Observatory. Soon a discussion emerged about the nature of this object on the MPML. Because it could not be found on previous images of the big surveys it was proposed that it might be a comet outburst. 

p_2010_h2_thumbAnother indication was the fact that other observers found a slightly elongated FWHM on their images, compared to field stars of the same magnitude. MPEC 2010-H12 was issued on April 17 by the Minor Planet Center announcing the discovery of a new Comet P/2010 H2 by J. Vales of Crni Vrh (106), Slovenia. Now only one day later our images made with the 14 inch show a well elongated object with a clearly visible coma. It is expected that the new comet will develop a more significant coma in the following weeks. 
Richard Kowalski of the Catalina Sky Survey ruled out that the bright object was not detected because of interference with bright field stars in all 4 frames made of the area by the survey. That means that Comet P/2010 H2 brightened in fact by at least 8 magnitudes within a day. That reminds of the massive outburst of Comet 17/P Holmes  in October 2007.
Comet P/2010 H2 developing

A few days after its discovery Comet P/2010 H2 (Vales) is further developing its appearance to a "real" comet. The former asteroidal NEOCP object 04F0011 now shows a nice 2' size coma.

P2010H2_10-04-1922_thumbThe left image was taken on April 19 and the right on April 22. Both shots were made with the 14 inch telescope and the SBIG ST8-XME camera in 2x2 binning mode. Exposure time was 40 x 30 seconds with no filter. Still there is no real tail but the false nucleus is slightly off center and the coma expands more to the northeast.
Comet Vales has a Hilda like orbit and circles the sun in a distance of 3.06 AU every 7.5 years. Hilda type asteroids have a stable orbit in a 2:3 resonance to Jupiter, which means that they orbit the sun 3 times for every 2 times that Jupiter does. So they stay away from the giant gas planet avoiding dangerous close approaches. But it is very likely that Comet Vales will be kicked out of orbit by Jupiter someday.