Observing Report: A New High

March 21, 2010

Last night I was back down at the Salton Sea. I got down there right at sunset, found a spot in the Mecca Beach campground, and got the scope set up a little after 7:00. The sites on either side of me were empty but I had neighbors farther down the way and across the road that runs through the middle of camp. I walked around and invited people to come see the moon.

About eight people drifted in over the next hour or so, and most stayed for quite a while. We looked at the waxing crescent moon, Venus, Mars, the Great Nebula in Orion (M42), the Beehive (M44), M41 in Canis Major, and Mizar and Alcor. Saturn got up out of the near-horizon murk so we got a good look at the ringed planet and four of its moons. Mars showed a polar cap, some dark surface detail, and a possible cloud near the equator. Eventually we went on to galaxies–M81 and M82 in Ursa Major, which looked awesome in the same field of view, M55 and M56 in Leo (ditto), M51 and its satellite, and, most memorably for me, the Sombrero Galaxy (M104). The dark lane of dust that runs across the Sombrero was easy to see, and under those dark skies the galaxy showed a surprisingly extensive halo extending above and below the plane of the disc.

I’ve started working on the AL Caldwell Club so I spent some quality time on a couple of planetary nebulae, the Eskimo or Clown Face Nebula (NGC 2392) and the Ghost of Jupiter (NGC 3242). The Eskimo showed its prominent central star or ‘nose’, and in averted vision I could see some detail in the gaseous halo, but it was small and short on detail compared to the Ghost of Jupiter. The latter nebula was just awesome–it seemed about twice the diameter of the Eskimo, and there were definitely at least two concentric shells of gas around the central star, with the inner shell being brighter than the outer and clearly elongated out of round. Look at this image from about ten feet away and you’ll have a pretty good idea of what it looked like in the eyepiece.

I got a good look at Omega Centauri, the immense globular cluster that just gets over the southern horizon here. It was suffering from being down in the dense atmosphere near the horizon, but it was still a big ole ball of stars. At 92x, it looked as big or bigger in the eyepiece than M13, the Great Glob in Hercules, looked at 184x, and its stars looked smaller and more numerous. It is truly an outstanding object.

And speaking of M13, it was pretty darn good once  it got a good way up the eastern sky, with lots of resolution and long chains of stars emanating from the central ball.

It was  great night. As much fun as I had during the Messier Marathon last month, I had more fun last night just surfing around the sky and showing people cool stuff. I got better views of planetary nebulae, globular clusters, and galaxies than I have ever had from my own scopes. But the most amazing thing I saw all evening was, believe it or not, the moon.

I set up the telescope right before dark, tweaked the mirror alignment, and got the scope on the moon just by dead reckoning, without using the finder. The moon was exceedingly detailed and the entire globe stood out very clearly against the sky, which was not yet fully dark. And the moon was surrounded by stars, which was weird. Admittedly, it was still just a crescent moon, but between the glare from the moon and the evening twilight I didn’t expect to see any stars at all in the same field. They were there,  though. It occurred to me that the moon might be passing in front of a star cluster, as happens from time to time. Finally I got around to checking the finder scope and saw that the moon was cruising right past the Pleiades.

The view in a low-magnification eyepiece was indescribably beautiful, but I’ll try to describe it anyway. With the sky not fully dark, the razor-sharp moon seemed to hang suspended in front of a dark velvet blue sky, with the stars shining out like a halo of fireflies. The impression of depth was overwhelming–I could almost reach through the telescope and pluck the visibly spherical moon from among the streams of stars. Intellectually, I know the distances are all wrong–the velvety blue sky was in front of the moon, not behind it, and the stars were incomprehensibly more distant–but that’s what it felt like.

I took my best photo from last night and mocked up a very crude representation of what this looked like at the eyepiece. Imagine trying to tell someone about Michelangelo’s David when all you have to show them is a doodled stick figure and you’ll have a sense of what I’m up against. Nevertheless, here goes (image processing in GIMP, star positions from Stellarium):

UPDATE: I made a much improved, more realistic version of this image and put it in the next post.

So, I have a new favorite sport: catching the moon in front of star clusters during twilight. I’m sure it won’t happen that often, but the memory of just this first catch will last a lifetime. It was, hands down, the most incredible thing I have seen in any telescope of any size, anywhere, ever.

Best of all, it was accessible–anyone pointing even the most modest telescope skyward at the same time last night would have seen the same thing. So stay alert, you never know when the most seemingly ordinary of celestial objects will jump up and blow your mind.


One comment

  1. […] Moon passing in front of Pleiades at dusk […]

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