Log, Jul 25, 2008

43 people. Well we had an excellent night for a change. The Moon did not interfere until the closing hour. The sky was very dark for most of the night. We did have a bit of moisture and a few clouds collected into puff balls late in the evening but generally we had excellent viewing.

The Milky Way Galaxy [MWG] was really beautiful. It is often obscured or only visible as traces but tonight you could make out dark lanes between the arms. Until recently, the MWG was thought to be a basic spiral nebula, but with the advent of better infra red telescopes which can pierce the dust and gas that obscures the central regions of the MWG, we have determined that it a variant form of a galaxy called a barred spiral. To get an idea what this is like, place your right arm in front of you curved to the left, and your left arm behind you curved to the right. Your shoulders are the "bar"; your arms are the two major galactic arms (Perseus Arm and Centaurus Arm). Our galaxy has smaller arms, two very closely wrap about the core and two moderate arms which used to think were major arms (Sagittarius Arm and the Norma Arm). These smaller arms would be like hands sticking out of our chest and back. The Sagittarius Arm was directly above our heads last night and we could see a "spur" of it sticking out of the main arm just south of the constellation Cygnus last night. Our Sun is tucked between the folds of the Sagittarius Arm and the Orion Spur.

Jupiter was spectacular last night. On an average night, I can see the north and South Polar Region and the equatorial belt in light colors with darker bands on what would correspond to the tropics on the Earth. Last night I could clearly see two lesser dark bands in the southern hemisphere. Ganymede was a distinct disk last night. Callisto was hit or miss as a disk as well. Normally, our turbulent air would convert these small disks to blurs or perhaps points of light.

Francine and I took out some badly needed time to realign the telescope to the 3 dimensional celestial coordinates. Due to weather, or poor viewing or large crowds we haven't done this in quite a while. Our telescope performed quite well but accumulated errors made finding dim objects nearly impossible. We did quite well. After the realignment, we were getting selected targets within the eyepiece almost every time, and just slightly off when we went to the far side of the sky. Ernie came in after packing up his 11 incher and asked to see M51.

M51 is the famous Whirlpool Galaxy. It is almost exactly face on to the Solar System making its arms distinct. It is having a close encountered with a somewhat smaller galaxy [NGC 5195], stripping stars from the smaller galaxy into M51 itself. The stars being torn off form an interesting "bridge" between the two galaxies and it was prominent last night. The arms of M51 never match the photographs - our eyes simply cannot grasp enough light to view them the way that timed photographs do. Yet last night all of us saw an impression of the arms.

We showed everyone Albireo. It never fails to be beautiful but it was hard to find last night. How so, you might ask since it is the head of the Swan where brilliant Deneb is the tail feathers? Well, we could see it well enough, but the finder scope couldn't. The edge of the dome shutter cut off about 30% of the view. I used a trick to center the pair. I took out the Moon eyepiece which is wide angle and centered the stars. Then I switched back to the higher magnification that we normally use. If we had taken out the time to align early (rather than late) it would have been no problem to simply ask the scope to find Albireo.

We looked at M3, M8 and M54 as well. We did a bunch of minor double stars including an interesting visual cluster of stars I have never looked at before near HD1200477.

-Les Coleman

Leslie Coleman
Leslie Coleman
Entry Date:
Jul 25, 2008
Published Under:
Leslie Coleman's Log
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