Diary

2006

Home

2007 

Wed, Nov 28

The weather turned perfect again due to another powerful cold front. I've been sicky since the observation on Nov 11 but now I healed. I could not get rid of the temptation from the mysterious comet 17P/Holmes. I made the observation with my 15x50 binoculars. This time, however, I caught the comet with a bit of difficulty, due to its low condensation and interferences from the light nearby and the strong moonlight. The rather large coma appeared to be oval-shaped. As my eyes adapted to the conditions totally, I gradually noticed a rather faint tail extending 1.0 deg. in p.a. 195. What a surprsing result it was! I ended my observation just before twelve o'clock.

Sun, Nov 11

Thanks to the great cold front over a week ago, the sky still stayed clear but worse than that on Nov 06. I woke up at three o'clock intend for the comet 17P again. Yet I felt sick for I have been tired for several days when I got up. Then I moved my refractor to the balcony as well as the 15x50 binoculars. Spoiling my mood that the disgust bright light was still on, which did interfered my observation. Thus the comet could not be seen with my naked eyes this time.

First I observed the comet through the binoculars that the comet became less condensed with a DC value of 5. Its surface brightness seemed to decrease a bit maybe suffering from the worse conditions. After that I observed the comet through the refractor at 70x. Immediately I was able to see the coma in two storeys: the outer coma appeared to be very large and round with a brighter edge surrounding the center and its brightness fading towards SSW; the small inner one stayed a bit off center in a higher surface brightness, evidently extending 6' from center on p.a. 210 deg as an ecllipse.

Having gilmpsed the comet at 28x later at about 5:30, I moved my instrunment indoors and went back sleeping. As I felt even more tired, I caught a fever and vomited after this observation.

Tue, Nov 06

The sky remained perfect so I could not help myself but to make an observation again of comet 17P. As the comet was located in the northern sky with a reasonable angle to zenith, I was able to make the observation in my bedroom.

While I tried to catch the comet first with my naked eyes, a very bright road-light near my house was lighting strongly. In spite of this, I still managed to see the comet with a condensed center and a broad coma at about 0:30. It was my first time that I have seen a comet with my naked eyes. A couple minutes later, I quickly used my 15x50 binoculars and made some estimates of the comet. Results are here.

Sun, Nov 04

A strong cold front swept South China several days ago bringing cold temperature and some rains, but finally remained a clear blue sky in daytime. I woke up at 2:45 in order to observe comet 17P/Holmes. At about three o'clock, I caught the comet with a very large coma and DC = 7 in my 15x50 binoculars sticking out of my balcony, however, it was still too high. I had to wait for minutes to look for a better altitude of the comet. As if I were deviled by an evil devil called 'cloud', I was overcasted again! I waited, waited, and still waited. Finally I still being in great 'luck', the sky gradually cleared up from east to west and Sirius was shining brightly, but the comet was about to set behind a tall buiding! I had to look for another day from my busy time.

Sat, Oct 27

I heard the break news of comet 17P/Holmes on Friday that this comet experienced a mega-outburst on Oct 24, thus its magnitude increasing rapidly from 16m or so to 3m within one day. Therefore I decided to make an observation of the wonder before dawn. However, at that time the weather was extremely bad that the sky was totally covered with strong fog and haze. What's worse, the full moon was hanging high above the horizon. As is often the case, no sooner had I assembled my 10cm-refractor in a open air near my house than I was overcasted. I waited for about 30 minutes, disturded by a great number of mosquitoes due to the hot temperature. Fortunately, I was seeing the area with the comet clearing up. After searching for a while using Capella, I caught the bright comet easily through my finder at about three o'clock, despite of such a bad condition. With 10cm 70x it looked like a planetary nebula with a bright condensed center. The small inner coma with a high condensation lay a bit off center to p.a. 250 deg. The outer coma appeared round but a little bit extending to the NNE. DC = 7 at this magnificent. At 28x, the comet just looked like a fuzzy star with a 'very' round coma 2.5' in diameter, total magnitude at 2.4, and DC = 8. I drew a sketch with both magnificents through the refractor. I ended my observation at about 4:50 local time.

Sun Jul 8

The weather keeping fine at night recently was caused by strong subtropical high pressure. In spite of my being in city today, I could still spot stars faint to about 4^m through tempting sky. I couldn't help but make an observation of comet C/2006 VZ13 (LINEAR). 

At about 01:30 a.m. local time, I immediately glimpsed a dim object at the predicting position, which surprised me quite a lot for I hadn't totally adapted to darkness. After slightly swaying my 10.0cm-refractor, I convinced myself of spotting the comet. However, a few of floating clouds were rushing northwards bringing me some interruptions. What's more, a great number of annoying mosquitoes were biting me fiercely. Anyhow, I successfully made some estimates of the comet and sketched, despite of some tiny troubles. 

Comet C/2006 VZ13 (LINEAR)
Jul. 7.76, mag.=7.6, Dia.=5', DC=4 ... Guangzhou, China, 0.10-m refractor (28x); 
City light pollution and floating clouds but transparent sky.  

At about 3:30 a.m., I ended my observation. 

Sat Jun 24-Sun Jun 25

I went to my grandparents' in northern suburban Guangzhou with my 0.1m-refractor in Sat. evening in order to observe 10^m nova V390 Normae and comet C/2006 VZ13 (LINEAR). Much to my surprise, the southward background has been much brighter than before due to the strong lights from a new road about 3 km beyond. Seems things are getting worse and worse. 

At about 23:30 local time, I quickly started to find V390 Nor for it was getting lower in the south. The moon was still highly in the west, which had some slight effect on my observation. What's more, the medium level clouds were developing slowly in south sky when I was observing, as is often the case. Unluckily, despite of trying my best, I still couldn't observe stars around the nova in the FOV faint to 8.5^m through the thin clouds and haze. I decided to wait for a moments, however, I was totally overcastted by the clouds. Finally, I failed to observe nova V390 Nor. Having been waiting for another hour and seen the sky conditions remained unchanged, I had to cancelled the plan my observation of comet C/2006 VZ13 in Cepheus and went to bed. 

The comets-ml group posted a claim of a possible comet in SWAN images reported by Rob Matson from the US waiting for ground-based confirmation. I also tried to make confirmation of the claim with my tiny refractor but failed due to the bad weather. Up to now no evidence supported Rob's finding with varieties of observations from outstanding comet-hunters. It was sentenced to death in the end unfortunately. 

On Sunday night I tried to observe nova V390 Nor again in the city, however, I failed again in spite of stars around the nova visible faint to 9^m. How I wish if I were still in the suburb! 

Wed, Apr 18

There was an extremely great shower yesterday afternoon that cleaned all the dust in the air and led to a transparent sky in this pre-dawn. I got up at about 4:10 a.m. without alarm's going off in order to observe comet C/2007 E2 (Lovejoy). In spite of the superb sky, it was still difficult to be seen due to severer city light pollution. If I had been in the suburb, more details would be caught without difficulties, surely. 

In the first half an hour, the area of the comet was just covered with altitude clouds. At about 4:50 a.m., I was able to catch stars close to the comet with my 0.10m-refractor 28x. Soon, I found a diffuse and faint object in the predicted position. In order to make sure whether it was the comet or my optical illusion, I waited for few minutes and observed again. Yah, it was still there. That was just the right comet. I got it. I quickly estimated its brightness shown as below. 

Comet C/2007 E2 (Lovejoy)
Apr. 17.88, mag.=8.2, Dia.=4', DC=3/ ... 0.10-m R (28x)
City light pollution and astronomical twilight. 

I haven't observed 96P/Machholz and 2P/Encke yet. Hopefully I will make at this weekend if weather permitting. 

Fri, Feb 23

After many days' raining, the sky happened to clear up yesterday's evening. A shower cleared all the fog and consequent bringing me the most transparent sky up to now in this year. How lucky I am! I was just back home from my grandparents' where I didn't have any telescopes. 

An alarm went off at about 3:00 a.m. and I got up for Saturn first. However, clouds covered Saturn transiently so that I had to wait for a moment. At about 3:30 a.m., Saturn got out of the clouds in the end. I immediately found three satellites around it without any difficulty. Thirty minutes later, clouds in the southern sky cleared up quickly and Scorpius was high already. I turned my refractor for V1280 Scorpii = Nova Sco 2007, near ε Sco. Despite of heavier light pollution above SE horizon, I caught it without any difficulty. Magnitude estimate was first done with single comparison star 5.0^m HR 6316 for no any brightness difference between them via my refractor. 

After having done the estimate, I sketch the nova. It would take me long to finish all the stars in the field with 28x. So, only those which are brighter than 10^m were sketched. 

With time flying by, the rather blue sky with some pieces of clouds was filled with sunshine gradually. Jupiter was lost in the end. All of these gave me a deep thought about the mighty universe. How lucky I am! I used to believe that I wouldn't have any chance to observe Nova Sco 2007 before. 

Wed, Feb 15

Using several images taken by Xing Gao (MPC Code: C42) on Feb 12, 2007, with his VIXEN ED114 F/5.3 + Canon EOS 350D (images here) , I make a magnitude estimate of a recent nova V1280 Sco = Nova Sco 2007, discovered by Y. Nakamura and Y. Sakurai, with six groups of comparison stars. Here comes my estimate:

I didn't have any chances to make my own magnitude estimates of V1280 Sco due to poor weather. According to the weather forecast, I'm afraid that I won't be able to observe this object in following days, which really upset me. 

Name: Sky chart of V1280 Sco = Nova Sco 2007 Position: 16h57m40s.91, -32deg20m36s.4 (J2000) Note: Stars faint to approx. 18m.0

Sun, Jan 28

A cold front attacked almost the whole South China yesterday which led to the coldest temperature recorded about 6℃ and poor seeing this predawn. However, the transparency was excellent. I got up at about 19: 45 UT for Saturn first via my 0.10m-refractor, f/7. I immediately caught three Lunæ Saturni (Saturn's satellites) without much difficulty including Titan, Rhea and Dione. Dozen minutes later, having adapted to the darkness already, I detected another satellite difficultly, Tethys, about 10^m.0, very close to both Saturn and Rhea. One of the cloud zones, yellow-brown colored, was obviously seen across the center part of Saturn with 140x. The Cassini Division was also clearly observable with the same magnificent in spite of poorer seeing. Sketch. 

When I finished observing Saturn, the Crux was getting down in the low south sky. I had a quick view of the Jewel Box Cluster, NGC 4755 via my 15x50 binoculars and even the finder to my refractor. Dozens of stars including κ Crucis, 5^m.9, was observable in the field. 

What a busy dawn! Jupiter brightly hung in the SE sky. I should have made a sketch of it, however, the sky had already brightened up. After pointing to it just for fun, I happened to find that Ganymede situated very close to Jupiter. Having known that Jupiter was to occult Ganymede at about 22: 40 UT, according to the software Cartes du Ciel, in spite of a rough time, still enough for my preparation, I decided to make an observation of this occultation with 140x. I started the timer at 22^h38^m30^s.647 taken from Chinese Timing Centre. A bright tinny spot was entering the round face of Jupiter slowly and finally completely occulted 5^m28^s.12 later shown by my timer. So the time of this occultation should be 22^h43^m58^s.767 including the influence of my individual error, average measured 0^s.198. Thus, the real time was 22^h43^m58^s.569. I could check the real predicted time afterwards in two online webs that one was 22^h43^m, another one was 22^h44^m. Anyhow it was close to the result gathered from my own independent observation. However, I was told that the "real" predicted time was 22^h37^m.2 according to the result taken from the professional occultation software WinOccult later in the morning. The strangest thing was, only the predicted time of today's occultation of Ganymede was different greatly. That's been making me confuse. Was that the refraction of Jupiter's atmosphere and the diameter influenced the data? In order to prove it, I will make more observations of Galilean moons' events in the following days. 

Galilean Satellite Eclipse Timing Report Form: 
Observer Name: W.-T. Xu                Apparition [Year(s)]: 2007
Location: Guangzhou, China (23d 9.212m N, 113d 18.965m E) 
Descript Your Time Source(s) and Estimated Accuracy: BPM±0.2s

Sun, Jan 14

C/2006 P1 (McNaught) :

After several failure attempts early in January due to pollutions and haziness, I finally manage to catch -5^m comet C/2006 P1 (McNaught) via my 0.10m-refractor this afternoon. It was my first time to observe a comet in daylight time. What a spectacular object in the sky! 

The sky was covered with thick clouds in the morning, but it sometimes it opened gaps for a moment since about 03: 30 UT. I moved my refractor towards my balcony immediately. Nothing has been detected near the position where comet C/2006 P1 was before another mass of clouds nearly covered the whole sky again. Sadly I had to quit my observation. 

Fortune came towards me again when it was at about 05: 45 UT that the sky turned to clear again. However, the sky was still hazy. I slowly and carefully swept the position near the sun. After lots of attempts and repetitions, just at about 7: 05 UT, a bright planetary spot burst into my telescopic field. First thinking it was my optical illusion but soon I was able to confirmed it being the great daylight comet C/2006 P1. When I was about to sketch and do some necessary measurements, the comet quietly ran out of my field for my manual- guiding telescope. It took me about 20 minutes to catch it again. It was an obvious object but easily left out. A white planetary face, with an impressive condensed centre coma, that was what I could only catch via my telescope though a rather long tail should have been seen according to foreign reports. I should have measured its brightness using Venus but failed. It seemed that the poor sky condition should be to blame or the comet was much brighter than Venus. So I could only make my own magnitude estimation according to my experiences in observing Venus in daylight times. 

Comet C/2006 P1 (McNaught)
Recent comet estimates:
Jan. 14.31, -5:, -- (W. Xu, Guangzhou, China, 0.10-m refractor; Venus invisible; daylight; comet alt. 33 deg; );

About some times later, I lost the comet again for my taking another eyepiece with higher magnification. I wasn't able to get it any longer. Cirrus and smog came above western horizon before sunset. I didn't think it was all right to catch it under such poorer circumstance. Consequently, I didn't make any further observations before sunset. However, I felt regret immediately for my friend Quanzhi's catching this brilliant comet again with only a few degrees above horizon on the same day. 

Anyhow comet C/2006 P1's been the brightest one since comet Ikeya-Seki in 1965. It's still been a lucky day for me. How impressive! I'll never forget its fabulous and tremendous appearance.  

Top of this page

Back... -- Zurück...