Observing at the ASSNE April 9th meeting

[petep]

Pete’s observing log of 9 Apr 05

We curtailed tonight’s ASSNE meeting to take advantage of the best observing night of the year to date. It’s been shirtsleeve weather all day and this evening’s conditions are perfect. I’d set the 12” up prior to the meeting among a dozen other scopes. Tonight I’m after a few more asteroids, and anticipating them being low I’ve positioned myself at the NW part of the field, or at least as far as I can go in that direction without being in deep mud.

We’re out of the meeting by 20:00, and its deep twilight. The scope auto-aligns on Denab and Procyon, and then I swing to M42. Even with the Orion Ultrablock filter the Great Orion Nebula is a bit less than Great, as its low and in the twilight. Half a dozen folks eyeball Orion before we move on.

Saturn is the next target. Seeing is really good, and we’re viewing easily at 250X before atmospherics become noticeable.

Jupiter is tonight’s third target. Callisto and Europa are stacked one over the other and for a while we’re puzzled as they’re not in line as usual. Matt explained that they must be on opposite sides of their orbit. And a later check with Guide 8 confirms that Europa is on the near side orbit and Callisto is on the far side orbit. Hmmm.

Now on to some asteroids…..

9 Apr 05, 21:19 hrs 674 Rachele is a bright 11.7 magnitude object 101 km in size. It orbits the sun at a distance of 2.7 AU and is now 1.9 AU from Earth. I’ve got it in the 12” at 97X star hopping from a bright star to the south and easily hopping stars as dim as 13.5 magnitude. It’s an exceptional night.

9 Apr 05; 21:42 hrs Asteroid 447 Valentine is a 13.6 magnitude object within 3’ W of a 5.7 mag star. I can’t see it in the 12” until I change over to a 20mm Plossl (156X), and then it’s pretty obvious. Brian Tjersland can’t make it out, but Jen Astrella sees it right off. Jen says she was using averted vision, and I suspect that I was too. Valentine is 82 km in size. It orbits the sun at 3.1 AU, and is right now 2.1 AU from Earth.

22:01 hrs After spending some time searching for it I give up on asteroid 2000 KP6. It is supposed to be 11.5 magnitude – an easy find. I’ve star hopped in to the plotted position, but I’m not seeing it. A 12.3 mag star next to where the asteroid should be is also dim – it’s more like 13.3 magnitude than 12.3 mag. Local cloud?

9 Apr 05; 22:07 hrs Asteroid 104 Klymene is a 13.2 mag minor planet 127 km in size. I’ve got it pretty quickly in the 12” at 97X by star hopping in from the west. Klymene is 3.3 AU from Sol, and is presently 2.3 AU from Earth.

9 Apr 05; 22:15 hrs 2 Pallas at a brilliant 7.6 magnitude. Pallas is a relatively large 523 km. It orbits the sun at 2.4 AU, and its now 1.5 AU from Earth. I’ve got it easily star hopping up through a bright field from a 6th mag star about 11’ south. Ruth Amaral also observes Pallas.

9 Apr 05; 22:28 hrs I’m shaking and shivering now from the cold. Time for an easy one. I put aside a 13.8 mag asteroid 537 Pauly in favor of Asteroid 410 Chloris which is a bright magnitude 12.0 It currently sits just below a crescent group of 12th mag stars, and fortunately is quickly identified in the 12” at 97X. Chloris orbits 2.5 AU from the sun, and is now 1.6 AU from Earth. Chloris is 128 km in diameter.

It’s only 37°F out, but I’m not dressed for it and am thoroughly chilled, so this is it for the night. After packing the scope back into the pickup I walk around for the dual purpose of checking everyone else out and getting the circulation going.

Conclusions & lessons learned.

Always be prepared to dress for cold. Always.

That really was a muddy part of the field. Didn't realize just how muddy until I unloaded the truck the following day and had to wash mud from just about eveything.

Pete