Observing log of 31 Jan 05

[Pete]

Placed the 12” out on the pier for cool down around 16:00. We’re in the middle of a very unusual 3 or 4 day clear period, and temperatures have moderated to the extent that today it got up to freezing. Roger called to say he’d be by for a while.

18:45 hrs. Roger arrives just as I’m powering up. Cygnus is finally below the workable horizon, so for alignment stars tonight I use Procyon and Capella. Perhaps I’m distracted, because it takes me three tries to run a proper alignment tonight. The sky is black. The stars are very clear and steady. Neighbors have voluntarily turned off lights.

19:00 hrs. Target #1 tonight is Comet C/2004 Q2 Machholz. In the 12” at 97X it appears as a round fuzz ball. The small intensely bright core exhibited when Machholz first made its appearance is no longer visible. And the overall brightness is markedly down – its now way down to magnitude 4.8. Machholz peaked at around mag 3.9, and its dimming so quickly now that it’s noticeable from night to night.

I ducked into the house and grabbed the 22 X 100 binocs. They mounted very quickly and readily on the revised pipe mount. Machholz has moved 5 or 10° since last viewed 3 days ago, so it took about 5 minutes of panning before we located the comet in the binocs. As usual, the view is far different than thru the scope, with a nice wide tail showing.

The temperature is in the low 20s now. I’m wearing heavy wool socks under thermally insulated boots, a fleece vest, a fleece sweatshirt, a very heavy wool sweater, a fleece neck tube, a very heavy wool watch cap, thermally insulated gloves, and a one piece snowmobile suit.

My young astronomer neighbor Sam arrived so I put the scope on Saturn for Roger to view while Sam used the binocs to check out the comet. When Sam sits down to observe Saturn, Roger excuses himself and ducks into the house to warm up (and to chat up Carrie).

Its time to hunt asteroids. Sam says he’s interested and is going to stick around. My 1st target is one of three asteroids located at 10 hrs RA, and it proves to be below Sam’s roofline. So we next try for 194 Prokne, but can’t match the fov with the Guide 8 printout. I synchronize the scope on Betelgeuse but we’re still not getting the right fov. So we agree to give up on Prokne for a while and try something else.

Mathew and his mom (neighbors) arrive to check out the comet. But the binocs have frosted over – apparently from the inside, and all stars look like comets at this point. So we slew again to Saturn and everybody ohhs and awwws before Mat’s mom ushers him to bed.

31 Jan 05; 20:00 hrs. 59 Elpis is an 11.8 magnitude asteroid 173 km in size. The go-to has the fov roughly correct, and I immediately pick up an easily distinguished star pattern that includes a bright 8th magnitude star and an 11th mag double star just above Elpis. Sam & I viewed Elpis at 97X in the 12”. Elpis circles the sun at a distance of 2.8 AU, and is presently 1.8 AU from Earth.

31 Jan 05; 20:29 hrs. Asteroid 358 Apollonia shines at 12.6 magnitude. The go-to puts us onto the Guide 8 printout, and I’m able to star-hop in from a 9th magnitude double in the SW, following several 11th mag stars in a zigzag pattern to reach Apollonia. Viewed at 97X in the 12”, but Sam can’t see it. Changing to the 26mm Plossl in (117X) makes it easier to view, and Sam’s got it now. This 91 km dia. minor planet circles 2.7 AU from the sun and is currently 1.7 AU from Earth.

Roger joins us briefly to view Apollonia before taking off to pick up Cathy.

31 Jan 05; 20:40 hrs. Sam & I take another shot at viewing 194 Prokne. At 12.4 mag, this asteroid should be easy to sight. The problem is putting the scope onto a fov that matches my chart. And it still eludes us. The scope is pointing almost right at Procyon (which I already used as an alignment star), but on a hunch I go-to Procyon and find it to be at the far edge of the fov. I resynchronize the scope on Procyon, and the next go-to finally gives us the asteroid fov we’ve been seeking. Star-hopping in from a 9th mag star in the SW we viewed Prokne at 97X in the 12”. A 13.7 mag confirmation star was visible nearby, and Prokne actually seemed to outshine an 11.2 mag star just below it. To the point where I had the two confused until viewing an updated chart for 20:45 on the morning of Feb 1st. (The charts we were working from were all set for 19:30 hrs.) Prokne has a dia of 174 km. It orbits 3.2 AU from the sun, and is presently 2.2 AU from Earth.

Sam’s chilled now, and heads for home. I only intended to stay out ‘till 21:00 myself. Thanks to my extreme garb I’m not feeling the cold yet.

31 Jan 05; 20:53 hrs. 133 Cyrene shines at 12.5 magnitude. The scope go-to is on-target and there are 3 10th mag finder stars in the S of the fov. The star field is very sparse. I’m seeing a 13th mag star in the 12” at 97X, and can readily view Cyrene. 70 km sized Cyrene orbits 3.2 AU from the sun and is currently 2.2 AU from Earth.

31 Jan 05; 20:58 hrs. Asteroid 52 Europa is a bright 10.0 magnitude. The scope go-to is right on target now, and thanks to a distinctive and not overly crowded star field I’ve got it quickly at 97X in the 12”. Europa is a relatively huge 312 km in size. It orbits the sun at 2.8 AU, and is currently 1.8 AU from Earth.

31 Jan 05; 21:03 hrs. 171 Ophelia is a 12.0 mag asteroid 121 km in diameter. It orbits the sun at 2.6 AU and is presently 1.8 AU from Earth. Ophelia is presently in a sparse and dim star field, but the go-to is accurate and while viewing Ophelia I’m seeing a nearby confirmation star that’s a relatively dim 13.4 mag in the 12” at 97X.

31 Jan 05; 21:09 hrs. Asteroid 84 Klio is only 13.1 magnitude. The initial go-to places two bright finder stars in the S of the fov, and star-hopping to Klio’s position, the asteroid becomes visible once I increased the 12 incher’s magnification to 150X. Klio is 83 km in size. It orbits the sun at 2.8 AU and is presently 1.8 AU from Earth.

Its 17° now, and my feet are starting to feel the cold.

31 Jan 05; 21:25 hrs. 149 Medusa is a 13.1 magnitude asteroid that’s only 22 km in diameter. This asteroid is bracketed by a unique trio of 10th mag stars to the E and a bright 10th mag star to the W. Star-hopping in from the E and centering the scope over where Medusa should be, I increase magnification from 97X (Nagler 31mm) to 147X (Nagler 17mm). I haven’t used this eyepiece on dim asteroids before, believing that the fewer elements in my 20mm Plossl provides more light throughput. But the wider field Nagler works well here, I’m viewing 13.1 mag Medusa as well as a 13.3 and a 13.9 mag confirmation star in the 12” at 147X.

The sky is beautiful for observing now. One of those rare nights that we only experience 2 or 3 times a year here in RI. But I’m cold and committed to knocking off early. So that’s it for the night.

Observations & conclusions.

When observing, you can never dress too warmly.

Using a pencil instead of a ballpoint pen does indeed work better in freezing conditions. The graphite in the pencil continues to work.

Pete