A short night, but a good night

[Pete]

Pete's observing log of 13 Feb 05

The sky will be clear for a brief while this evening, so around 16:30 I set the 12” out to cool down. Lou arrives around 17:30 while I’m still plotting asteroids. He sets up his new (used) 10” and I join him shortly. It’s around freezing with a slight breeze. The sky is clear and dry, and the neighbors have cooperated and turned off their exterior lights. We’re both dressed very warmly. Both scopes align without a hitch – I’m on polar & Lou’s on Alt-Az.

Because my polar alignment go-to hasn’t been highly accurate I sync the scope on several stars in the area I’ll be searching tonight. Roger & Cathy arrive as I’m searching for my first asteroid of the evening.

13 Feb 05; 18:27 hrs. Asteroid 63 Ausonia is a relatively bright 11.9 magnitude object, but I’m not seeing it in the 12” with the Nagler 31 eyepiece (97X). It does become quite visible once I change to the Nagler 17mm (179X). Roger checks it out, and Lou sees it as well. The sky isn’t as dark as one could hope for due to a 30% phase moon that’s still high toward the west, and that probably explains why we had difficulty with an easy object. Ausonia is a 108km sized rock currently 2.0 AU from Earth and orbiting the sun at 2.7 AU.

13 Feb 05; 18:52 hrs. 752 Sulamitis is a relatively dim 13.6 mag. Fortunately it sits in a nest of 4 nearby stars, and by continually increasing magnification I’ve finally got it in the 12” at 339X (9mm Plossl). This 66 km sized asteroid orbits the sun at 2.3 AU and is presently 1.5 AU from Earth.

Roger dressed warmly, but unfortunately Cathy didn’t, and they had to leave after only about ½ hour.

19:28 hrs – after working for ½ hr and going all the way up to 339X I finally give up on 13.5 magnitude asteroid 359 Georgia. I’ve got the field nailed down. But can’t see it.

19:43 hrs – after another 20 minutes of unsuccessful searching I give up on 13.6 magnitude asteroid 312 Pierretta. I’m seeing something but the asteroid is too far from any bright reference star to confirm.

13 Feb 05; 19:52 hrs. Asteroid 152 Atala is a bright 12.7 magnitude. It was viewed thru the 12” at 97X (Nagler 31). Atala is approximately 142 km in diameter. It orbits the sun at 3.0 AU, and is currently 2.0 AU from Earth.

13 Feb 05; 20:02 hrs. 110 Lydia is a 12.0 mag minor planet 89 km in diameter. In the fov of the 31mm (12” at 97X) it’s the westernmost of 4 12th mag objects forming a small crescent. Lydia is presently 2.0 AU from Earth and it orbits 2.9 AU from the sun.

13 Feb 05; 20:04 hrs. Asteroid 264 Libussa is a relatively bright 12.6 magnitude, and it’s within a few minutes of a 7th mag finder star. I’ve got it immediately in the 12” thru the Nagler 31 (97X). Libussa is about 53 km in size. It orbits the sun at 2.9 AU and is presently 1.9 AU from Earth.

13 Feb 05; 20:07 hrs. 487 Venetia is a relatively bright 11.8 mag minor planet 64 km in size. It’s in a sparse field, but near three other 12th mag objects that simplify locating it in the 12” at 97X. Venetia is now 1.7 AU from Earth. It orbits the sun at 2.7 AU.

13 Feb 05; 20:11 hrs. Asteroid 118 Peitho shines at 11.8 magnitude. It’s in a sparse field but I’ve got it at 97X with the 12” while seeing down to 13.05 mag. Peitho is approximately 46 km in size. It orbits the sun at 2.2 AU and is now 1.2 AU from Earth.

There’s a haze forming to the N and to the W. It’s close to time to pack it in. I put the scope on Saturn with the 17mm Nagler (179X). I can see the Cassini division and some dim banding but this is all the magnification Saturn will take tonight. Titan, Rhea, Tethys and Dione are visible. Lou is observing thru his new 10” and thinks he has also identified Ipetus.

It’s now 20:36 and we pull the plug.

Observations & conclusions:

Everything went better than planned for such a short evening. I’m surprised to bag 7 more asteroids tonight.

Lou was pleased with the very big bright images we were viewing thru the 10”. I’ve always maintained that 10” is the critical size for amateur work, as its big enough to view just about everything that amateurs chase.

Pete