Saturday, September 3, 2011

Supernovae and comets

Last Saturday night I drove out to the airstrip with the 15-inch, where I met with fellow members of the local astronomy club and a few friends. Sky conditions were not very good however, the seeing was very poor but the Milky Way was easy to see and more stars than usual were visible to the unaided eye.  Among the numerous objects observed that night, all of us looked at Comet C/2009P-Garrad, which was still in Sagitta very close to a nice double star. The tail was more noticeable while to me the coma and nuclear region became more diffuse. I'll be watching this comet for as long as possible, it's not often one stays visible for as long as this one will from the Earth.
One of Draco's many deep sky objects is the edge-on spiral galaxy NGC-6503, visible in small telescopes from a good site and an interesting object through larger ones. While it was a small oblong glow in my small 6-inch, it became a larger mottle lens shaped object through the 15-inch at 250X. NGC-6503 wasn't especially bright, either my eyes were not quite fully dark adapted or the skies increasing milkiness was attenuating the galaxy's faint light. Nevertheless, it was a object worth revisiting.

Another galaxy in Draco I visited was the multiple arm spiral galaxy NGC-6643, which shows it's spiral arms studded with star forming regions in photographs. While the spiral arms were not visible at 250X that night, the nuclear bulge was noticeable and the disk did seem somewhat patchy. This galaxy requires high magnification to make out well against the sky glow for Mobile and other nearby cities and towns.

Among the other objects I searched for was the face on spiral galaxies M-51 and M-101, both of which now have a supernova underway in them. SN2011dh has now faded from view in M-51, probably more because of the hazy skies, light pollution and the fact a dim pip of light is hard to see among the glow of the galaxy's spiral arms. SN2011fe was visible but I couldn't tell it apart from other foreground stars in our own galaxy. At the time that supernova was as 13th magnitude but now it has zoomed up to 11th magnitude, making it much more visible.

While the skies were clear at first and the Milky Way was plainly visible, sky conditions were not very good that night. The seeing was very poor, and stars remained blobs. There was surges of warm humid air mixed with cooler drier air passing through the  observing site, but strangely enough dew was minimal. Usually everything is soaking wet when I take down the telescope and put it in the car for the trip back to my house. That night everything was still mostly dry, but as I took down the telescope thin high clouds precluded observing any more deep sky objects.

Other objects I and my friends looked at are the planetary nebulae M-57 and M-27, NGC-6826, NGC-6781, NGC-7009 and NGC-7293. Those are located in Lyra, Vulpecula, Cygnus, Aquila and Aquarius respectively. I've also showed them the nebulae M-8, M-20, M-17, M-16 as well as the Veil and Crescent nebulae in Cygnus. The galaxies M-31, M-33 and NGC-7814 were among the others I examined before taking the telescope down and driving back home.

I hope to try again with SN2011fe during the next club star party to see if I can spot it against the glow from M-101's nuclear bulge, and make more drawings of my favorite deep sky objects.

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