Feeling lucky when Lulin shining above
I departed with a few friends from Guangzhou for Gaocun Village at around 22:30, Heng Zhou drove the car. It's our Guangdong Southern Cross Star Association which held the party, and there is only one topic -- Comet Lulin. It was prefectably clear all the way down, but according to the messages from those friends who arrived earlier, "it's overcast!" We laughed and refused to believe, as the sky was really "rarely-seen prefect".
At around 0:15 we arrived Gaocun and had to believe what was told earlier -- it's indeed overcast. What made us feel more frustrated is that we were under a small patch of heavy cloud, the patch went just right over the village. After a few minutes of discussion, we made a casual decision that a new temperory site must be found. Quanzhi Shen and several others would stay at Gaocun since their equipment could not move easily, while Heng, I, Jianji Li and some others (2 cars in total) would drive east to seek for clear sky. We made a U turn and drove about 10 kilometers to reach the clear sky we had found on the way to Gaocun, but quite unfortunately, when we found a flat area near Xiaodong Village after about half an hour's search and were just about to unpack our equipments, the clouds came and blocked our view. Disappointed and frustrated, we decided to go back Gaocun, set up our tents and sleep. At around 1 a.m. we arrived Gaocun and began to set up our tent. "Lulin is shy," I explained to others, as I had predicted the sky to be "partly clear" that night but it seems not, "she is unwilling to turn up when there are so many guys pointing their telescopes to her."
We worked 20 minutes to set the big tent up, but just at the time we finished all the things and plan to go to sleep, Heng's mobile phone rang, it came from another group which had also went out to seek clear sky, "You said that the sky is clear there?" Heng shouted, and we were all stop talking to hear what he went on, "drove... west? Okay, okay, we're coming." After only five minutes, Heng was driving at about 150kph at the tiny path heading west and we were on his car (Quanzhi Shen and his fellows stayed still at Gaocun). At about 1:40 we arrived Picun Village, the group arrived earlier had set up a temperory observing field on the ground in the front of the local goverment building. Everyone was unpacking their equipments with a hurry. I, too, dragged my 11x70 binocular out from my bag as quickly as I could. Less than 15 seconds did I spotted comet -- it's almost impossible to miss that bright, fuzzy, lovely target, with a mild anti-tail pointing east, that's really gorgeous! I measured its brightness to be 4.6, with a ~25' coma and a tail at a length of ~1.7 deg. Heng estimated the brightness to be around 4.2 with his 10-cm refractor. We could spotted it easily with naked-eye, the estimate is about the same with the binocular's -- around 4.5 mag. with a 30' coma, but I couldn't detect the tail with naked-eye.
Xun Zheng, a journalist of the Evening News who had monitored activities of our association for a long time, took some nice photos of us, and two of them were printed on the Yangcheng Evening News later that day. After obtaining Xun's permission, I'm posting some of them here.
I also took a glance of a few dozens Messier objects with my binocular before the sky turned bad at around 5 a.m. We learnt later that the sky of Gaocun also became clear but still far from Picun's. As an old Chinese saying goes, "Man proposes, but God disposes." For any astronomical activities, no matter how well you prepared, the God only need a patch of cloud to let your preparation get ruined. We were very lucky to get 3 hours clear sky that night.
As spaceweather.com had reported, Lulin's tail is changing rapidly. Around Feb. 22 the ion tail suddenly showed some complex structure, but on Feb. 25 the ion tail was torn away by a solar win gust (I'm not fully agree with this solution; it might as well be the geometry effect which had made the ion tail disappeared). On the other hand, the appearance of the comet appeared to be about normal (as the structure of ion tail is not visible to visual observers under most occasion), except the main tail is an anti-one: it points directly to the sun! But after Feb. 26, the double-tail Lulin will become mostly single-tail since the comet has passed the opposition point and the geometry effect (see my earlier explanation) disappears. Stay tuned for updates!
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本文发表于2009 February 25 20:38,归类为一图胜千言, English Island, 观星手记。您可以通过RSS 2.0来订阅有关的评论。 您也可以留下评论或在您自己的站点跟踪引用。 This entry was posted on 2009 February 25 at 20:38 and filed under 一图胜千言, English Island, 观星手记. Follow any responses to this post through RSS 2.0. You can leave a response or trackback from your own site. |
约4年前 about 4 years ago
好漂亮的星空!^_^