The rather full moon doesn’t rise until 20:00, and I don’t think that I’ll last too long in the cold, but the sky will be great in the early evening despite the snow cover.
17:45 Performed a 2 star polar alignment on Denab and Betelgeuse. Then went in for dinner and to warm up.
18:30 I'm dressed with heavy wool socks under thermal boots, a valour vest and sweatshirt, a very heavy wool sweater, a full body thermal worksuit, and a very heavy wool watchcap. Plus gloves. It was 20° when I did the setup. Its now down to 12°F, but there’s no breeze and the sky is dark and clear with an unusual number of stars visible overhead. Several neighbors have bright lights shining off of the snow – and some are being used so I’ll just have to tolerate them this evening. The go-to after polar alignment hasn’t been particularly accurate, so I synchronized on Capella before starting the evening’s asteroid hunt.
28 Jan 05; 18:56 hrs. Asteroid 105 Artemis shines at a dim 13.6 magnitude. This 123 km dia. minor planet is presently 2.3 AU from Earth and 2.8 AU from the sun. The star field has some bright locater stars. I’m continually increasing magnification as I close in on the asteroid, and finally I'm working with locater stars as dim as 13.8 magnitude. At 150X I catch a few brief glimpses of Artemis as it fades in and out despite the use of averted vision.
I’ve turned the 12” on Pluto (13.9 mag) many times and most of the time I can see it, so considering tonight’s very good conditions I’m surprised that Artemis proved to be so difficult. I’d hoped to hunt several 14th magnitude asteroids tonight but given the difficulty of achieving 13.6, I’m going to reset my sights a bit lower and leave the 14th mag observations for when I’ve got the 14” out.
28 Jan 05; 19:06 hrs. 195 Eurykleia is a 13.2 magnitude asteroid now located just south of a bright line of locater stars. Two of the locaters are bright doubles so I’ve identified the field very quickly. With the 12” scope I again work up to 150X to see Eurykleia, but it’s much easier to view than the previous 13.6 mag asteroid. Eurykleia is 90 km in dia. and is presently 1.9 AU from Earth and 2.8 AU from the sun.
Now it’s into the house for warm-up and to sort out my next targets.
28 Jan 05; 19:24 hrs. 238 Hypatia is a 12.8 mag asteroid currently 2AU from Earth and 2.8 AU from the sun. Its 156 km in size. Once I’ve centered the star field per my Guide 8 chart identification comes pretty quickly. Although at 12° nothing is quick or easy. Viewed in the 12” at 97X.
28 Jan 05; 19:48 hrs. 804 Hispania is a relatively bright 12.6 magnitude. I’m slightly confused when matching my fov to the printout, but quickly figure out that one of the bright locater stars on the chart is a “non star” and doesn’t really exist. Once that hurdle is crossed I switch to a larger scale printout and put a 26mm (115X) eyepiece into the 12”. Hispania is easy to find with the increased magnification as I’m seeing locater stars as dim as 13.3 mag in the sparse star field. Hispania is 161 km in size and is presently 2.2 AU from Earth and 3.1 AU from the sun.
Once more I duck into the house to warm up and select the next targets from the printouts I’ve prepared.
28 Jan 05; 20:00 hrs. Asteroid 568 Cheruskia shines at 12.9 magnitude. It’s in a crowded star field, so I’ve 3 different scale charts to work with. There’s a bright distinctive pattern of bright id stars in the fov, and once I’ve got the fov matched with the chart I change to the large scale chart and put a 20mm (150X) eyepiece into the 12”. I’m seeing locater stars as dim as 13.7 mag, and Cheruskia is not that difficult to view tonight. Cheruskia is 90 km in size and is presently 1.7 AU from Earth and 2.6 AU from the sun.
20:15 hrs. Asteroid 1963 Bezovec is 13.2 magnitude, and it lies in a sparse and dim star field. At RA 10 hours it’s far in the east, and the newly risen moon is wiping out that section of the sky, making it unworkable tonight.
28 Jan 05: 20:34 hrs. 618 Elfriede is a 13.2 magnitude minor planet. I can’t see any of the bright locater stars in the fov after the initial slew. But since Elfriede is in Gemini I slew the scope to Pollex and resynch. The subsequent go-to is dead on, and the fov matches my chart printout. At 150X in the 12” I catch a glimpse of a 14.2 mag star while confirming Elfriede. This asteroid is 124 km in size. It orbits the sun at a distance of 3.4 AU, and it is presently 2.4 AU from Earth.
That’s it for asteroids tonight. Ducking into the house again to warm up I note that it’s down to 7°. I print out the current position for comet Machholz and for Saturn’s moons before going back out.
20:44 hrs. The moon is still below the neighbor’s roofline and the sky, being quite dry, is still dark. Comet Machholz is dimming rapidly now – it’s down to 4.7 mag. In the 12” at 97X its just a round fuzz ball surrounding a small bright core that isn’t as bright as it was in the month or so before the comet peaked but when it was at this same magnitude. Unlike the binocular view of the previous night, there is no distinct tail visible.
21:00 hrs. Saturn is shimmering in the eyepiece at 176X. I can see 9.8 mag Rhea, 10.3 mag Tethys, 10.2 mag Dione and 8.4 mag Titan. But I can’t even see 11.8 mag Enceladus. Perhaps the rising moon has washed out this part of the sky now. So there’s not a chance of checking out the condition of the Hugens space probe on the surface of Titan. Bummer.
The sky to the south is still dark, and on a lark I go-to the Horsehead nebula. I think that with the Nagler 31 at 97X I can see a trace of nebulosity, but it isn’t distinct. Installing the Orion Ultrablock narrow band filter doesn’t help a bit.
Keeping my eye to the eyepiece while the scope makes a short slew to M42, I notice that I pass over a bright nebulosity with 3 bright embedded stars. M42 is big & bright with the Ultrablock on the nose of the 31mm. But it’s now down to 6° and I’m getting numb.
I manually slew back to that bright nebulosity and hit IDENTIFY, but the scope just replies M42. A later search on the computer will reveal that there’s nothing between the Veil and M42. Hmm. Maybe I was just traveling over a bright piece of the Veil or an upper piece of M42?
21:15 hrs. That’s all the cold I can handle for tonight. I pack it in.
Observations and conclusions:
I’ve come to the conclusion that the reason that my alt-az mounted go-to performance is better than my polar mounted performance is due to the pier not being precisely polar aligned. I saw a reference to this in a Yahoo user group message. Don’t know if I want to invest the time to properly align the wedge when I’m starting work on the dome.
I’ve discovered a wonderful tool in Guide 8 called “Line of Variation”. And now I’ve got my charts set up with a line representing the orbital path of the asteroid for 30 minutes before and after the calculated time for which the asteroid is plotted. This way I can identify the fast movers without guesswork - even if they’re out of position due to not viewing them at exactly the proper time.
Tonight I developed a solution to the hand controller freezing and subsequently malfunctioning when used in Artic conditions. When entering coordinates for an asteroid, I hold the controller in my ungloved left hand and do entries with my thumb while holding a hairdryer on my hand and on the controller. Keeps the hand warm, keeps me from hitting the wrong keys with frozen or gloved fingers, and keeps the controller bright and responsive.
As I write this up from my rough notes the day after the observing was performed, I think that although it was cold as a witch’s heart out there, I was right about it being the last night before the clouds moved in for a week. It’s almost dark, and the clear sky we enjoyed all Saturday has a heavy cloud line representing a front coming in from the west. Its warmer, but we’ll be clouded out by 19:00 hrs. So I got me some more asteroids. And a cold.
Pete
