2009
Sat, Oct 10
I managed to make a final observation of Jupiter on Oct 07
night before leaving home again for Wuhan. The transparency has somewhat
decreased to estimated 2/6 ALPO as a result of the deteriorating air quality.
The observation was started at about 22:40. With my 10.0cm-refractor f/7 + Plössl
10mm + 2x Barlow, I found the image of Jupiter was poorer
than the results of the latest two observations since the seeing was also
declined to only 5/10 Pickering, in my estimate. When the seeing occasionally
recovered to about 7/10 Pickering, I could see, making all my efforts, two
darker knots (or maybe two barges in fact?) in the middle NEB, with a subtle
festoon extending, as well as a faint and dim spot in the STB. Besides, no many
more details were visible.
Sketch.
During the observation, I observed the start of a transit of Io. The results are
listed as follows, noted that there was a great uncertainty as the seeing was
mediocre so that my timing must have been strong affected:
Time Source and Estimated
Accuracy: BMP ± 0.2s
Predicted Time (UT): 2009/10/07 15:27.9 UT
Observed Time (UT):
C1 Time: 2009/10/07 15:23:50.75
C2 Time: 2009/10/07 15:30:19.01
(individual error excluded)
Individual Error: 0.25s
Telescope
Data
Type:
Sky condition (0～2 Scale)
Seeing: 2; Transparency: 1;
From my data I
am able to roughly calculate the diameter of Io as about 3.5
×
103 km approximately, relatively close to the true value 3.6
×
103 km, if influence of the poor seeing is taken into consideration.
(I'm afraid I was calculating the Airy's Disk since theoretically the apparent
diameter of Io is still beneath the resolution power of my refractor.)
The whole observation was completed at about 23:40, to be followed by a rather
long silence since I am away from my telescope.
Tue,
Oct 06
I made two observations of Jupiter on Oct 04 and Oct 05 respectively. The
transparency remained superb while the seeing on Oct 05 became somewhat poorer
than on Oct 04. The observation of Jupiter was started at about 22:50 local
time. I could make out three festoons extended from the southern edge of NEB,
and besides, a dark knot in the NTB was visible, barely, at 140x with the
10.0cm-refractor f/7.
Sketch. The observation ceased at 23:50. On Oct 05, I
attempted to seek out comet C/2006 W3 (Christensen) as the glorious moon
was not so high in the east. Yet despite making every effort, I still failed to
catch anything dim and fuzzy at the predicted position at 28x since the city
light pollution was always the arch-hindrance to amateurs who is unfortunately a
city dweller. Thus I switched to observing Jupiter at 140x at some 22:40 and
then immediately found Ganymede disappeared, compared to the position given by
the software, while other Galilean satellites remained in their respect
positions accurately in accord with the software. Under the impression that
something wrong had occurred with the software or even with my computer, I
concentrated on Jupiter itself. An evident fracture nearly in the middle NEB
accompanied with an obscure festoon extended from its west was detected. Other
subtle festoons were grudgingly visible only when the seeing became better.
Sketch. I finished the whole sketch and went indoors to log the observation
record, with the more serious doubt of the miraculous disappearance of Ganymede,
so I decided to go outdoors again to review the Galilean satellites maybe at
00:20 UT (in my memory other than consulting the real time). Strangely Ganymede
appeared in the given position, with an abnormal fainter magnitude -- only about
7m (no estimation made)! I went indoors again to check the software
and checked online whether an occultation had once occurred but no advance
result was returned. I again reviewed it about ten minutes later, and found that
Ganymede had already brightened up to its normal brightness -- 4m.7.
Later as I checked thoroughly finally I understood that there was a Ganymede's
eclipse by the great umbra of the Jovian planet, which was omitted in my
prediction table. It was my first time to come across such an event. I was
insatiable as I attempted to observe the mutual occultation between Ganymede and
Io at around 01:15 am, Oct 06, yet I was held back for the inferior seeing. So I
had to make a halt of the observation at 01:15 am.
Fri, Sep 04
I strove to make couple observations this predawn before leaving home for Wuhan,
despite the acute moonlight and severe city light pollution. I first managed to
catch comet C/2006 W3 (Christensen) with my 0.10m-refractor at about
00:40 am, when the area around the predicted position cleared up. The comet was
only barely visible under such circumstances, so no detail in the coma was
caught. After applying three stars, i.e.,
TYC 1065-588-1 (mV
= 7.92, B - V = 0.110), TYC 1065-1456-1 (mV = 8.84, B - V = 0.015), and TYC
1065-721-1 (mV = 8.66, B - V = 0.138),
by means of Sidgwick's Method, I obtained the total visual brightness m1 = 8.5.
Other values were also estimated during the observation: Dia. = 2', and DC = 5.
Preceding the Jupiter observation when completing the comet observation without
sketching, I tried to capture it with Canon EF 70-200mm f/2.8 USM + Canon EOS
350D. The seeing was mediocre to average with much clouds interference during my
observation, however, I still managed to make out several dark knots in the NEB
as well as other details in the disk.
Sketch. I finished the observation at
about 2:50 am, and half an hour later or so, I was overcast.
Sat, Aug 22
A negative
observation, as I expected beforehand, of comet C/2006 W3 (Christensen)
was made at about 2:30 am this predawn, since the sky was still hazy that made
the light pollution severer, and the altitude of the comet was low already. But
fortunately I succeeded to capture it with Canon EF 70-200mm f/2.8 USM + Canon
EOS 350D before my observation started.
Images. I
had to finish the whole observation quickly as I glimpsed Jupiter later but
found the seeing mediocre.
Thu, Aug 20
The weather has been so nasty for a relatively long period recently that I could
not make any observation. The condition turned a little bit better after
yesterday dusk, however, frankly speaking, that it was only suitable for
planetary observations, rather than cometary observations or any other ones as
the sky remained hazy. As Jupiter already rose high enough in the south when it
was 23:50 or thereabout on Aug 19, I started my observation of Jupiter with my
10.0cm, f/7 refractor. Despite the mediocre transparency, the seeing was
increditably excellent only with rare disturbances that would worsen the
condition, so bulks of details on Jupiter was clearly visible at 140x. The GRS
with a dark spot closely to its west was again to disappear on the preceding
limb and several dark knots in the North Equatorial Belt (NEB) were visible as
well. Surprisingly I could still make out the diffuse impact mark detected by
Anthony Wesley, however, compared to the last view of it twelve days ago, it
appeared to be more elongated in E-W, parallel to the cloud belts. The impact
mark seemed to be even more obvious, unexpectedly, than the last view mainly
owing to the supreme seeing. During my observation, I
sketched what all I could
resolved on Jupiter. Marked one
here. The
observation ceased at 1:00 am on Aug 20.
Sat, Aug 08
I specially did a midnight session to observe the impact mark on Jupiter, which
was discovered by
Anthony Wesley, an amateur astronomer and planetary photographer on July 19
2009. Despite that no any known object had been predicted to plunge into Jupiter
beforehand, the mark immediately evoked people's reminiscences of the impact
scars created when fragments of comet D/1993 F2 (Shoemaker-Levy 9) struck
Jupiter in July 1994. Further analysis made by professional observatories
confirmed the new feature as an impact scar indeed.
I moved the 10.0cm-refractor out to the balkony and started my observation just after 0:00 am. Couples of cloud belts were clearly visible yet the Great Red Spot appeared very vague on the preceding limb at 140x, since the average-to-mediocre seeing always prevented me from viewing some subtle features on Jupiter clearly. During some rare steadier moments, I could reluctantly make out a very diffuse and subtle small dark mark elongated E-W creeping along steadily to the central meridian with the rapid rotation in the South Polar Region (SPR). The mark was much fainter than I had anticipated. It will continue dissolving and thus it is bound to vanish in Jupiter's atmosphere within the following weeks. I sketched the impact scar as well as all the detail features I could detect. Marked one here. During the observation Europa gradually emerged behind Jupiter after an occultation by the Jovian planet at about 00:23 am. As the transparency was poor with strong moonlight interference I could not make any comet observation, therefore, I concluded the whole observation at 00:50 am or thereabout.
Tue, Aug 04
I flew to Chongqing, a municipality in southwestern China, on Jul 21 dusk with a
beating heart enroute, after checking the weather charts again and again since
the weather prediction given at the time during the great total solar eclipse
this year was incredibly poor, and hence eventually making the final decision on
Jul 20 afternoon. It was very hot when I got to the destination yet the clear
sky soothed me to some extent. Meanwhile, I kept praying for a sunny day on Jul
22. Gods bless me!
I became very excited as I understood that the eclipse observation was likely to be successful since I saw a wonderfully clear sky but some cirrus clouds low in the west after drawing the curtain apart as soon as I got up at around 6:30 am. I arrived at a opening grassy lawn in front of the Jiangbei Airport Hotel where I met Siwei Luo from Xinjiang as well as several amateur astronomers from other provinces by taxi with my devices: a Canon EOS 350D, a Canon EF 70-200mm f/2.8 USM, a set of camera tripod, and a processed Baader solar filter (neutral density 5.0). Despite of setting off at around 7:00 am, the arrival time was delayed to almost 8:00 am due to the taxi pausing to refuel at a gasoline station. The surroundings of the lawn are acceptable, environed by a corner of the airport to the east, the hotel situated to the north, and two roads to the west and to the south respectively but separated by flourishing woods both. The sky conditions somewhat got worse then that the cirrus clouds previously from the low western sky early in the morning had moved eastwards and thus an evident halo around the sun emerged. Having assembled all the devices, I immediately focused the lens and tested the shots in order to obtain the best images. Unconsciously the eclipse has already begun during my hurry. A small eclipsed piece of the upper sun (in p.a. 285 deg. approximately, inaccurate estimate) was clearly visible from the FOV of the camera under the protection of the solar filter at around 8:09 am. Time was gliding, and the degree of obscuration was increasing, however, I was still adjusting the focus of the lens all the time for I did not feel confident at all whether the figure was accurately in focus or not. Furthermore, the proper exposure used during the partial phase imaging often fluctuated for the varied amount of the cirrus. Contrary to the circumstances before the eclipse begun, sometimes gentle breezes came up, bringing some relatively cool air along. In the meantime, the air temperature decreased somewhat as well. I started my recorder attached to the mobile phone and time adjustment at some 9:02 am since recording will benefit me in two main aspects: that the accurate times of the C2, C3, and C4, respectively, can be deduced from the record afterwards by means of software analysis, and that the reactions of people around including me and even animals will be recorded, being a priceless reminiscence later on. A crowds of sparrows suddenly became very noisy and in tumult, twittering and flying up and down among the woods in the south at some 9:03 am. Over a minute later, they all returned to silence. At about 9:10 am, the brightness of the background sky visibly obviously decreased. The people around me all seethed with excitement and burst into screaming cheers at about 9:13 am when the sun gradually turned to a glaring oval pearl -- the diamond ring! Soon as the pearl dwindled out, an extremely narrow arc of the pink chromosphere emerged along with several small prominences. Meanwhile the mild corona became clearly visible, but exuded very soft white light, which greatly differed from the last magnificent view of the totality from Xinjiang last year, maybe due to the scatters from the cirrus clouds. Luckily the cirrus around the totality turned thinner and thinner, therefore, the corona appeared to be brighter and clearer that the eastern part and western part of the coronae both approximately symmetrically diverged with regard to a central line almost parallel to the ecliptic elongated from the sun. I enjoyed observing the sky with naked eyes during an interval particularly squeezed out of my intense photograph. I found that the brightness of the deep-blue background sky was evidently dimmer than that of last year, and that the orange lower area along the horizon was somewhat hazy and dirty ascribed to air pollution and light pollution from the airport. Venus was my only visible star in the sky in the vicinity of the lunar limb. Mercury must have been omitted. How careless! As no one conducted reporting time, I hurried back to photograph to seize the final opportunity for imaging the corona. The upper (western) corona became brighter and brighter, clumps of prominences emerged on the upper lunar limb, including a spectacular one which was reported to be visible even with naked eyes afterwards, and eventually, without any preparation, the stunning Baily's Beads abruptly penetrated the sky, and then quickly extended to a dazzling arc, like a fabulous diamond ring, a great sight to be held, leading to another great outburst from the people about. The totality concluded...
The solar filter was re-installed 30s or thereabout after the C3 for safety and I imaged a few shots of the very narrow crescent sun. I was drowned in relaxation and joy when finishing checking the *decent* images during the totality, yet I suddenly discovered that I forgot to switch the image quality from 'L' format to 'RAW' format! How regretted I was! I scheduled to switch the image quality to RAW format as soon as I switched a new CF card; actually, however, I concentrated all my attention upon focusing accurately even when the totality was to perform. Next time I should select RAW format at the beginning before photographing events. Never should the mistake occur again! Nevertheless, I was quite satisfied with my observation of the totality since I have already behold such a great spectacle with my own eyes. I was favored by fortune!
The partial phase after the totality appeared to be bland, compared to the breathtaking view during the totality, so great numbers of the dwellers around us who just planned to experience the beauty of the totality now gradually withdrew back home, and only a few stayed till the eclipse ended. I used to try to play with the pinhole images of the sun projected onto a piece of paper, however, the spots were only some very pale blurs due to the interference from the cirrus clouds. At 10:30:57 am (predicted time, the record not yet analyzed) the whole eclipse finally terminated, only to left an incredibly clean solar disk without any sunspots. It seemed that nothing has ever occurred. A sense of great void upwelled in my mind as the conclusion of the eclipse came to me in this way... The valuable experience of the total solar eclipse will be an eternal memory in my rest life.
On the evening I flew to Shanghai to participate in the IWCA IV held on the next day, visited Hangzhou by train, where I met some amateur astronomers of Chinese-origin from Malaysia, and finally flew back to Guangzhou on Jul 27. Here I would like to specially acknowledge my parents, who have given me numerous supports during the journey, Uncle Wang, who has warmly treated me when I was in Chongqing, as well as many uncountable colleagues who have ever helped me.
Sun, Jul 12
I have been absent from night-sky-observation for a rather long time due to my
busy study in university but now I can finally return to my favorite field again
since I am now having the relaxing summer vacation. Yesterday two heavy showers
attributed to a tropical depression called Soudelor passing in the South China
Sea swept all the dust in the air away, only to reveal an rarely extremely
transparent sky afterwards late at night. Despite of situated in a big city with
much light pollution and a bright waning moon rising in the east, I was able to,
unbelievably, catch sight of a glimmer of the milky way, so that I determined to
catch this rare opportunity to observe the relatively bright comet
C/2006 W3 (Christensen).
I brought my 10.0cm-refractor out, at about 1:00 am, to a small garden some 100m away from my home where I had a wide field of vision. The flaming moon contaminated the whole sky, however, my NELM reached to about 5.0 overhead still. Under such circumstances I did not think there would be too much difficulty in successfully observing the comet. After hopping from Scheat (β Peg) to Matar (ε Peg), then to π Peg and finally to the predicted position of the comet, I immediately detected it at the very sight without any difficulty incredibly. It appeared to be a fuzzy object with a condensed pseudo-nucleus in the centre. I was always interrupted by the fast moving clouds during my estimates, yet luckily they were just passers-by. At last I obtained m1 = 8.6 (three comp. stars applied in the Morris Method: TYC 2722-1450-1, mV = 8.98, B - V = 0.300, and TYC 2721-2236-1, mV = 8.45, B - V = 0.471, and TYC 2722-1906-1, mV = 8.22, B - V = 0.459), Dia.= 3', and DC = 6 on 11.75 UT in the 10.0cm-refractor, f/7, at 28x. Later I sketched the comet. The comet's motion was obvious within two hours. I ceased my observation at 4:00 am.
The comet keeps in good conditions over the coming several weeks so I think I will have more chances to observe it if weather permits. By the way, I've made a couple observations of Jupiter and its four brightest moons on 9th and on 10th morning, respectively, when the sky was fairly hazy, yet the observations of Galilean satellites eclipses are all negative due to a wicked cloud's trick and failing in receiving the time signal separately.
Fri-Sat, Mar 13-14
The sky eventually cleared up on yesterday afternoon after a strong cold front
sweeping here in Wuhan, which concluded weeks' annoying drizzles, and thus I was
able to make an observation of comet C/2007 N3 (Lulin) when I finished my
last two classes, despite that I caught a cold and was feeling sick. (Actually I
have observed this comet on Mar 9 when the moonlight extremely affected my
observation yet it had to be a short observation since I needed to go to class
the next day.) I went
upstairs to the roof of my dormitory with my 10x50 binoculars at about 9:00 pm.
It was at some 9:45 pm that I finally caught the fading comet convincingly since
my eyes had entirely adapted to the dark circumstances. The long-time adjustment
of my eyes might be caused by my feeling of sickness. Anyhow, I did manage to
detect the fading fuzzy comet whose diameter was 13', DC was 3/, and visual
total brightness was 6m.0 by applying two stars nearby in the
Sigdwick Method through the bonoculars, yet I could not capture any other detail
of the comet since my binoculars were not powerful enough and the sky background
was contaminated with city lights and the brightening moonlight as well. I
finished my observation at about 10:30 pm.
Surpringsly there was even another improvement of the sky transparency today. As I know comet C/2007 N3 is fading now and I may lose sight of it within following months for the limiting capability of my binoculars so every clear sky is extremely valuable for me. Therefore, I made another observation of this comet tonight. It was not until 9:00 pm when the powerful decorative lights of several tall buildings about 3 km away were off that the NELM rose to about 5.0 around the zenith and the comet was also cleraly visible through my 10x50 binoculars. The coma, measured to be 14' in diameter, still appeared to be globular without any elongation detected in such conditions. The degree of condensation was rated as 5 yet seemed to be a much higher value apparently for a 8m.12 star situated close near the pseudonucleus of the comet. The visual total brightness was estimated as 6m.1 in the Sigdwick Method by applying three comparison stars, namely, TYC 1355- 489-1 (mV = 5.94, B - V = 0.323), TYC 1373- 613-1 (mV = 6.24, B - V = 0.924) and TYC 1359-2673-1 (mV = 5.24, B - V = 0.447) whose magnitudes were taken from the Tycho Catalog as the names suggested. The whole observation terminated at 10:00 pm. I don't know whether I was able to make more observations of comet Lulin in following days. Hope I can if the weather coorperates.
Sat, Feb 21
The sky gradually turned clear early yesterday morning unexpectedly after a
whole week's consecutive drizzles. As I know, the weather in Wuhan within the
following few months will be nasty undoubtfully, therefore, how can I miss such
a rare opportunity to observe comet C/2007 N3 (Lulin)? So I determined to
make an observation before my sleep. At about 2:00 am, I walked upstairs onto
the roof of my dormitory with my 10x50 binoculars and a pencil, as well as some
sheets. The outdoor temperature was still very low so my gloved fingers were
painful. Nevertheless, I was very satisfied with the sky conditions. The naked
LM was some 5.5 near the zenith. In this case it was reasonable that the comet
was obviously visible in the binoculars. The coma appeared evidently larger and
brighter, whose DC was rated as 5 and diameter was 16'. The pseudo-nucleus was
seemed to be a bright knot situated at the center of the coma. It took me
couples minutes to catch details in the coma. By means of slightly shaking the
binoculars I was able to convincingly detect that the coma was elongated,
stretching in two opposing directions, viz., in p.a. 110 deg and p.a. 300 deg
respectively, with averted vision. Additionally, the subtle extension or maybe the tail already in
p.a. 100 deg stretched longer than the one opposite. Finally I estimated the
visual total brightness of the comet to be 5m.1 in the Morris Method
by applying two comparison stars nearby, namely, TYC 4930-1093-1 (mV = 4.30,
B - V = 0.982), and TYC 276-1189-1 (mV = 5.36, B - V = 0.004).
I concluded my observation at about 3:00 am and went to bed subsequently. Were I in my home, I fairly convince that the 10.0cm-refractor will ensure me to catch more details of the comet if weather permits.
Sat, Jan 31
I woke up at some 4:00 am this predawn with my alarm going off for observing comet
C/2007 N3 (Lulin). The sky remained extremely transparent. I captured the target
again without any difficulty through my 0.10m-refractor set in the balkony. The
comet, whose total visual brightness was estimated as 6m.8 in the
Morris Method by applying three comparison stars nearby, viz., TYC 6174-1051-1 (
mV = 6.87, B - V = 0.969), TYC 6174-1069-1 (mV = 7.59, B - V = 0.289), and TYC 6188-1530-1
(mV = 6.68, B - V = 0.395), has moved about 2.5 deg in p.a. 100 deg with respect to
the stars in the vicinity. The medially condensed coma was some 7' in diameter,
appearing to elongate in p.a. 90 deg and p.a. 270 deg respectively without evident changes compared to what I observed yesterday. Afterwards I sketched the
comet at both 28x and 70x. How lucky I was! As soon as I concluded the whole
observation at 6:00 am, clouds gradually gathered and finally the sky became
overcast again.
Fri, Jan
30
I returned home from my hometown Pubei, Guangxi yestreday. Despite of taking
my 0.10m-refractor there duiring the spring festival, depressingly I have not
made a single observation due to the nasty weather all along this period. When I
was about to go to bed at about 3:00 am, I was delighted to found that the
clouds was gradually collapsing to reveal an extremely transparent sky,
attributed to the continuous rain washing away most of the airborne dust
particles. In this case I determined to make an observation of the bright comet
C/2007 N3 (Lulin) in Libra. Since the comet was still low in the SE sky, first I
practised focusing with a borrowed Canon 30D equipted with a 70-200mm, f/2.8
lens. At about 4:00 am when the altitude of the comet became enjoyable, I began
my observation and immediately managed to capture it, a very obvious fuzzy
object in the FOV, as soon as the refractor was pointed to the predicted
position. As I concentrated the whole energy upon my observation, I was able to
notice the comet, anchored by the rusty 28 Librae as well as many other fainter
stars in the southernside, appeared to elongate in p.a. 90 deg and p.a. 270 deg
respectively. The former extension was subtle and blunt while the latter
appreared slightly more obvious, tapered and finally blending in the background.
The coma was measured as some 7' in diameter with an unexpecting quite high
condesation at 28x. However, when I switched an eyepiece to observe the comet at
70x, I was surprised to detect that a star (TYC 6175-46-1, mV = 10.66, B - V = 0.837)
just happened to interject itself inside the central condensed coma in reality,
which interfered with my DC estimate made at 28x. I sketched the comet in my
notebook and attempted to photograph it with the DSLR preceding estimating the
total visual brightness of the comet because I convinced me that I could
finished all the items before the twilight, which proved to be wrong
subsequently. Unconsciously the astronomical twilight has already begun after I
completed my shots, therefore, comet C/2007 N3 was nearly lost in sight. I made
a quick estimate of the visual brightness of the comet with two comparison stars
nearby as quickly as I could. The final struggle enabled me to work out the
value as 6m.8. Never will such a mistake occur again. Eventually I
completed my observation at 6:15 am and then made up my sleep.
Sun-Tue, Jan 18-20
I returned home by air on Jan 17 afternoon. The sky was still
excellent even if it has not rained for almost a month, which is absolutely
impossible in the heavy industrial city Wuhan. Only at about 1:00 am on Jan 18 did I
remember to observe comet 144P/Kushida when I was busy cleaning my
0.10m-refractor. I quickly moved my refractor to the balkony and pointed it to
the predicted position of the comet, yet only finding nothing aside from several
stars in the FOV, since the altitude of the comet was only some 20 deg then. The
sky obsessed me to a large extent so I determined to stay up to observe another
bright comet, namely, C/2007 N3 (Lulin) at predawn, regardless of heavy
city light pollution and the moderate moonlight. After taking a shower I went on
observing. Yet I found masses of clouds were moving eastwards from western sky
and soon I was overcast. Luckily the sky cleared up again at about
5:15 am and
therefore I was able to observe comet C/2007 N3. Initially I spent some time
mistakenly searching the area southeastern off in Lupus (Inertia?! I forgot I
was not in Wuhan already...) but soon I realized it
and got to the right position in Libra navigated by rusty twinkling Antares. I
immediately saw a fuzzy glow in the FOV, in which the LM was about 10m.5, without any difficulty in spite of
strong artificial light pollution in this direction and some moonlight. I knew I
have caught
the comet! As I focused my concentration upon this comet, I saw its 8' coma, with
a central condensation, DC=5, extended in p.a. 100 deg and 290 deg respectively.
The total visual magnitude was estimated to be 7.0 using the Morris Method with
three comparison stars, namely 6m.65 TYC 6193-1355-1 (B - V = 0.457), 6m.84
TYC 6190-1876-1 (B - V = 0.390), and 7m.53 TYC 6194-256-1 (B - V = 0.256).
The LM in the FOV reached 10m.5 approximately. I finished my
observation at 6:15 am.
In order to observe comets under better circumstances I went to my grandparents' in Huangbei, northern suburban Guangzhou this evening with the refractor. However, I was astonished to find that the bright road lights along a newly-built road to the west of my observing lot severely contaminated the southern and western sky, which really upset me. It seemed that this lot was ruined forever. Nevertheless, I first attempted to observe comet 144P high in the western sky at about 23:00 but uexpectedly detected nothing obvious in the predicted position of the comet. But later I did manage to capture a fairly subtle and diffuse object, eliminating the possibility of optical illusion. The comet was supposed to be a rather bright one in my imaginariness. The LM in the FOV was already some 11m.5. The coma, 4' in diameter and DC = 3, appeared to be insipid without any evident details maybe due to the interference from the road lights, whose total visual brightness was estimated as 8m.9 by means of applying three comparison stars in the vicinity using the Sidgwick Method. The comparison stars are listed as follows:
TYC 1249-658-1 8.75 B - V = 0.491
TYC 1249-969-1 8.96 B - V = 0.511
TYC 1249-640-1 8.55 B - V = 0.433
After the observation I glimpsed Saturn, accompanied with its three satellites, and then went to bed, leaving my refractor on the roof, intending to observe comet C/2007 N3 on 19 Jan predawn. Yet the alarm attached to my cell phone did not work so that the twilight had already begun when I rushed onto the roof after waken by the noises of crows in a sudden. To make matters worse, I was surprised to find that my refractor was totally covered with dew. It should have been moved indoor... I wasted a good opportunity...
I continued observing comet 144P on Jan 19 evening. I started my observation of this meridian transit comet at about 21:00. Still no detail of this faint comet was captured although the LM in the FOV reached to 12m.0. The subtle round coma was 4' in diameter, the same as the value obtained on Jan 18, with a diffuser appearance, viz., DC = 2. This time I applied four comparison stars nearby to estimate the total visual brightness of the comet more precisely:
TYC
1249-658-1 8.75 B - V = 0.491
TYC 1253-508-1 8.30 B - V = 0.495
TYC 1253-371-1 9.27 B - V = 0.600
TYC 1249-500-1 9.44 B - V = 0.381
Finally it was estimated to be 8m.8. Having completed the observation of comet 144P, I went to bed and 'succeeded' in waking up with the alarm at about 4:30 am on Jan 20. However, when I moved my refractor to the balkony on the 2nd floor, rather than on the roof, I was shocked to detect a great mass of clouds were sweeping eastwards fiercely in the western sky. I had to compete against time. I quickly pointed to the position of comet C/2007 N3, a few degrees away from the waning crescent. Still, I managed to catch this bright comet at my first glimpse. There were not many obvious changes except for a slightly shrinking size due to the moonlight. The two subtle elongations separately in p.a. 100 deg and p.a. 290 deg were still visible. As the comet was to be obscured by the clouds, I only applied two comparison stars, TYC 6193-1355-1 and TYC 6194- 256-1 by means of the Morris Method to estimate the total visual brightness of the comet, which was measured as 7m.0. Several minutes later, the comet was swallowed up in the clouds. I had to finish my observation at about 5:30 am and returned to sleep.
According to the weather forecast the weather in following days will be nasty caused by a strong winter monsoon, therefore, I will be able to enjoy some relaxing sleeps at nights to enable me to convalesce from fatigue.
Sat, Jan 10
I woke up at 4:15 am and climbed up to the roof of my
dormitory for observing comet C/2007 N3. The temperature outdoors, for me, was
intensely low, only -3 Celsius. My fingers were rather painful in the chill even
if having been gloved. Nevertheless, the transparency was good with a
naked LM around 5.0 near the zenith although a waning moon was still blazing
away in the west. Several flickering stars in the head of Scorpius was just
rising over the top of Luojia Hill so I began my observation. The comet was reluctantly visible initially
as an extremely subtle glow without any detail in the predicted position through
my 10x50 binoculars. As the moonlight dwindled and the comet rose higher, the
comet became more evident piercing the FOV anchored by 47 Librae and
λ Librae nearby in the eastside. The coma, some 4' in
diameter with a central condensation, appeared to slightly elongate in p.a. 90
deg and p.a. 270 deg. The total visual brightness was estimated to be 7.3
using the Sidgwick Method by applying three comparison stars in the vicinity.
Yet no more details could emerge through my binoculars despite my every effort
having been paid off since the moderate city light pollution in this direction
as well as some trifling fog or haze in the low sky interfered. Had there been
no light pollution, I am sure I would have captured more subtle details of the
comet.
I completed my observation at 6:15 am. Now comet C/2007 N3 is increasing its brightness so I really anticipate to detect some of its impressive structures two weeks later when the new moon cycle returns with my 10.0cm-refractor in some dark conditions in my hometown.
Thu, Jan 1
Miraculously I managed to observe comet C/2007 N3 (Lulin) this predawn. I
woke up at 4 am and went upwards to the roof of my eight-floor-dormitry some
half an hour later with all my thick clothes on since it was extremely cold
outside, maybe only freezing point. The sky was clear with a naked LM probably
around 4.0 at the zenith, however, the city lights still interfered strongly, especially from
the SW to NW. Fortunately the comet was in the SE, where there was less light
pollution. The stars in the vicinity of the comet was found to has just rised
above the block Luojia Hill. In the first hour I could not see anything
comet-like in the predicted position of the comet besides some stars near the
border between
Scorpius and Libra. But as the altitude of the comet increased, I suddenly detected a
barely visible fuzzy object right in the position at first glimpse via my 10x50
binoculars, the only instrument I brought to Wuhan, after an interval at about
5:50 am. My unprotected hands in great pain due to the sharp frost, therefore it
was really a challenge for me to stick to holding a set of binoculars without
many trembles in such a freezing temperature. Yet eventually I was able to
confirm the suspected object was comet C/2007 N3. The coma was about 3' in
diameter, with a central condensation DC = 5. The total visual magnitude was
toughly estimated as 7.6 by using only two comparison stars in proximity for the
astronomical twilight had begun and hence many of the faint stars were lost in
sight.
I completed my observation at about 6:20 and then rushed back to my dormitory to escape from the chill weather.
