Wednesday, March 28, 2012

Supernova in M-95

Spring has arrived and with it more rain, clouds, wind and all around bad weather for stargazing. Last weekend was the first one where the weather was co-operative. The previous weekend saw clouds passing though but despite that I went to the airstrip where I looked at mostly winter deep sky objects. Last weekend with the better skies I concentrated on galaxies and planetary nebulae, as well as a comet and a recently discovered supernova. In both cases I loaded the 15-inch telescope into the car and drove out to the airstrip, where the weather was warm enough that I only needed my lightweight battle dress uniform blouse to stay warm. Before I was putting heat packs in my boots to keep my feet from suffering because cold tends to creep in through the soles of your boots when you are on cold ground for hours on end. The good news is with the weather comes a plethora of galaxies, galaxy groups and galaxy clusters even for those who have modest telescopes. Owners of large telescopes have many choices of galaxies to look at, way too many to even keep up with.
After taking a look at the Orion Nebula, the open cluster M-41 and Comet Garrad, I swung the telescope to the first main object of interest that night, the Leo galaxy M-95 and the supernova SN2012aw which appeared scarcely a week before. It's now brighter than 13th magnitude and was easy to spot through the 15-inch as a star on the outer edge of M-95, once I figured out where to look for it. The theta shape was seen with difficulty because the skies at the site are quite badly light polluted and transparency was only average. This core collapse supernova took place in the galaxy's outer ring, apparently having once been a star resembling Antares or Betelgeuse. It must have been spotted after it's maximum because it's now fading. Observers who enjoy looking for supernovae in other galaxies should also look at NGC-4790 in Virgo which has the supernova of it's own underway. SN2012au is now at a magnitude of 13.5 very near the center of the galaxy. The Leo galaxy NGC-3239 is also the site of another supernova, now fading at a magnitude of 14.5. This one is designated SN2012A. For the latest information on supernovae and novae, follow the link below.

Comet Garrad is still fairly bright and well placed for observation, but not for much longer. It's round with a bright core and seemingly still signs of a tail. It's motion is now taking it Ursa Major towards Lynx and Cancer. So if you haven't had many opportunities to see it, you will want to be looking for it over the next few weeks before the fading accelerates. 
While at the site I decided to look over some deep sky objects in the constellations Hydra and Sextans. The first was the planetary nebula NGC-2610, a fairly small object that had a faint ring shaped structure. It was dimly visible without a nebula filter at 227X, but an O-III filter improved the view. No sign of the central star was evident with or without the filter. While nowhere near the showpiece NGC-3242, the Ghost of Jupiter is, NGC-2610 reminded me of a little round smoke ring adrift between the stars.
The fairly bright but small galaxy NGC-2935 appeared readily through the 15-inch, even through my low power wide field eyepiece. It's inner core was a tiny fuzzy oval at 83X, which through my 15-inch using a 24mm ES 82 degree eyepiece gives a field of view one degree across. At 227X the galaxy presented a much better view, with signs of it's nuclear region and it's disk shape. Like our galaxy, NGC-2935 is a barred-spiral galaxy, but it's fairly low altitude in the hazy skies prevented the outer portions of this beautiful galaxy from being seen. This galaxy is not very well placed for observation from the southern U.S., but those in more southerly regions of the globe can see it high overhead. It's spiral arms would be visible to large amateur telescopes from dark sites. This is one objects I'm going to return to at a later date.
NGC-2974 is a very small but bright elliptical galaxy in Sextans, close to the brightest star in Hydra, Alphard the Solitary One. It is the only bright star in the area. After making an attempt to find the large ring shaped planetary nebula Abell 33, I turned my attention to this little galaxy. Shining at about 11th magnitude, it bears magnification well. In photographs a star is superimposed on one end, but I did not see it, probably because the seeing was not very good that night nor did I use extreme magnification. It's definitely in reach of smaller telescope from less than pristine skies.
While most of the objects I search for with telescopes are galaxies and nebulae, sometimes I also look for stars of unusual interest. VY Canis Majoris will explode as a supernova that will be as bright as a quarter moon and visible from just about every inhabited region of the globe. At very high magnifications a tiny disk can be seen around the star, with a bluish white jet sticking out if it. So far, I had the best views of VY Canis Majoris at 425X, doubtlessly folks in more southerly locations can go a lot higher with larger telescopes. The jet has been compared to the Nike "swoosh" logo in fact by users of very large telescopes. The disk is material expelled from the star by stellar winds, and the jet is more material being shed from the star from it's poles. The shedding of mass is VY Canis Majoris' way to try to stabilize itself but it will not prevent the core from collapsing into a neutron star or black hole. When that happens, VY Canis Majoris will certainlybe one of the most powerful supernovae ever to be seen from the Earth,

Other objects I observed but did not sketch included the Ursa Major galaxies M-51 and NGC-5195 as well as M-81 and M-82. The spiral structure was nicely visible and in the case of M-82 the ragged dark bands were also apparent. M-81 shows the faint outer arms surrounding the relatively large and bright nuclear bulge. In Leo I looked at the Leo triplet and the other bright companions to M-95. Other galaxies in Leo I looked at include the bright barred spiral NGC-2903, the NGC-3190 galaxy group, the interacting pair of galaxies NGC-3226 and 3227, and another spiral NGC-3162. In Coma Berenices I looked at NGC-4565 and 4494, both spirals. In the case of NGC-4565, the dust lane looked like a streak of ink along much of it's length. I visited the globular clusters M-3 and M-53, and amazingly I even succeeded in teasing faint NGC-5053 from the sky slow. Like a Cheshire Cat, I was seeing the grin of it's brightest stars dimly glimmering in the eyepiece. Down in Corvus I stopped to visit an old friend, the edge-on, massive spiral galaxy M-104 which does look much like a Sombrero. Before taking down the telescope and heading home, I paid a brief visit to Markarian's Chain and then the great globular cluster, Omega Centauri. Stars were resolved down to the core, the cluster glittered like tiny diamonds on a black bolt of velvet.

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