2011
Fri,
Dec 30
I had never expected to conduct comet hunts when
away home, yet I did manage to make it, as I was able to freely use a 13.0-cm
f/5 reflector atop Mt. Mulan, some sixty kilometers away from downtown Wuhan in
the north, on Dec 24 predawn. Benefitted from its elevation, the majority of the
dust particles were accumulating far below, and therefore, the sky was normally
excessively transparent when cloudless. The winter Milky Way appeared very
evident to unaided eyes. Prior to midnight, I successfully observed dozens of
DSOs through an electronically mounted 15.0-cm f/5 reflector, including (only a
part of the list which I failed to recall fully) M 31, M 32, M 110, M 33, M 103,
M 42, M43, NGC 1975, M 78, NGC 2024 (a.k.a. Flame Nebula), M 81, M 82, M 101, M
51, M 106, NGC 5195, M 65, M66, and NGC 3628, probably in this order. I found no
difficulty identifying these objects even when my eyes have not yet totally
adapted to darkness.
I started exploiting the 13.0-cm reflector after around 2:30 a.m. to observe comet 49P/Arend-Rigaux first. Albeit the limiting magnitude in vicinity was down to over 14.5, I still failed in detecting the comet. Perhaps the comet was too faint to be spotted, or more probably, a close encounter with a nearby star of mV = 12.4 contaminated the surrounding darkness, thus leading to my negative observation. On Dec 23.82 UT, m1 = [13.4, Dia. = 1'.0 presumably.
I commenced the session of comet hunt at 3:55 a.m., from Gienah Ghurab, viz. γ Crv. Only three minutes later, a relatively bright and somewhat diffuse object entered the FOV, which was identified to be planetary nebula NGC 4361 after I referred to the star chart. It was at 4:08 a.m. that NGC 4965 entered into the FOV as the first galaxy I could recognize, with a crisp rim. NGC 5292 along with two other fainter companions NGC 5302 and IC 4309 came into the FOV at 4:35 a.m. Only three minutes later, fabulous M 83 entered in; it appeared rather bright! Some six minutes later, another excessively faint blob of light caught my notice, which later was identified to be NGC 5182. So wonderful that I was capable of catching galaxies thus faint! And there were far more to come. At 4:50 a.m. NGC 5085 came into the FOV. As I had to be preoccupied with referring to star charts again and again, the search rate was inevitably quite slow. At 5:05 a.m. there moved in another faint galaxy near the edge of the FOV, NGC 4856, which took me long to identify as I found myself lost in the stars. Later I was asked to help my friend Zhu Mao for awhile, and I restarted the search from where I left at 5:17 a.m. Eight minutes later Sombrero Galaxy M 104 entered the FOV, how impressive! Nevertheless, owing to the low power, 26x, I failed in making out the dark lane across the galaxy. Five minutes later, I could see yet another galaxy NGC 4700. It was 5:37 a.m. when NGC 4856 once again entered the FOV. Meanwhile, I could not recognize NGC 4902 nearby, weirdly. Perhaps two nearby stars of 10m were too bright. Later, at around 5:40 a.m. NGC 5018 entered the FOV, whilst two adjacent galaxies NGC 5022 and NGC 5006 eluded me. Only four minutes later, I was able to recognize a galaxy-triplet NGC 5068, NGC 5084, and NGC 5087. It took me eight minutes to encounter with another triplet -- NGC 5302, NGC 5292 and IC 4329, all in Centaurus, which were also the last galaxies I could pick up during the session. For one thing, I felt fatigue and cold as a result of no sleep beforehand. For another, my concentration was fully distracted by another mission that I intended to observe the tail of comet C/2011 W3 (Lovejoy). I swept across three bright stars in Centaurus one by one within a short spell -- Menkent (θ Cen), ψ Cen, and η Cen at 5:56 a.m., 5:59 a.m., and 6:01 a.m., respectively. Soon as I reached downward to the horizon at around 6:02 a.m., I concluded the session. Needless to say, it was by far the most successful session of comet hunts, in that I had never picked up thus numerous DSOs during sweepings.
After the session, I noticed the southeastern sky was fully drowned in the luminous zodiacal light. Mercury was shining merely above the horizon, yet both my friend and I misrecognized it as Antares due to the rusty color, how silly! Prior to sunrise, I had discerned no hint of the tail by naked eye whatsoever. A layer of haze and thick dust was noticed below 3° all along above the horizon. In the meantime, I attempted to take photographs of the so-called expected region, which turned out to be incorrect. In fact the pointing area should have been a few degress southwards, obstructed by a few withered branches in that direction. After all my subconscious remained what I have learned at my latitude. Generally speaking, the attempt was negative. Perhaps had there been free from the haze layer, I could have been capable of detecting some features of the tail, or at least I would have managed to capture them in my photographs. Anyway, it was truly a pity!
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Sun, Oct 30
The sky was cloudless and transparent before I
went to sleep, yet when I got up at 3:30 a.m., clouds prevailed in the sky. When
large patch of eastern skies turned cloudless, alas it was nearly 4:20 a.m. I began
the first downward sweep from Mars at 4:28 a.m. but on sweeping past the region
between Regulus and η Leo, clouds blocked my view. I
was forced to change to search from Tania Australis (μ
UMa) at 4:50 a.m. in that the proximity was the only eastern skies that had not
yet been covered with thick clouds. During the sweep I realized that there were
some thin clouds after all. Five minutes later I encountered a
faint cometary object that entered the FOV. However, before I could identify it,
clouds rolled in and all the stars were hidden. I had to wait until ten minutes
later when clouds moved out and revealed the stars again, therefore, I could resume
the check, which yielded that the object was NGC 3319.
I went on to sweep the skies but had to be interrupted for several times due to the clouds, how annoying! A satellite of about 5m moved across the FOV northwards at 5:23 a.m. 12 minutes later another object that appeared cometary came into the FOV, somewhat brighter than NGC 3319, which I suspected it might be NGC 3675. Unfortunately clouds interrupted my identification once again! On the clouds leaving the area four minutes later, I started to check the cometary object -- it was definitely galaxy NGC 3675. Having finished the check, when the eastern skies had been dawning, I concluded the session at 5:40 a.m. as well, really unsatisfied.
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Sat,
Oct 29
It had been nearly two months since my last comet hunt, but this predawn I
managed to conduct another session. Unlike previous ones, I did not sleep before
the session but directly commenced after completing the observation of comet
C/2010 G2 (Hill), which was proven to be a wrong tactic. As for the observation
of the comet, it was a successful but, undeniably, somewhat challenging one
owing to light pollution. At the beginning there was interference from some thin
clouds and therefore the effect was dissatisfactory, but luckily the clouds
dispersed and revealed a very transparent sky. The comet appeared diffuse with a
feeble condensation, only sighted by averted vision. I tracked the comet for
over 1.5 hours, within which its displacement was clearly noticeable. On Oct
28.78 UT at 48x, m1 = 10.6, Dia. = 3', DC = 3/.
I trained the scope near the zenith, switched to another eyepiece yielding 30x, and after focusing, surprisingly I found that M35 and NGC 2158 were both right in the FOV! Stars were extremely dense, like lustrous jewels! Some stars appeared reddish and orange, how picturesque! I then trained the scope to Praesepe M44, where I started the first sweep at 3:58 a.m.
Mars entered the FOV at around 4:07 a.m., but I failed to notice its apparent disk at 30x. I knew I was to sweep regions abundant with galaxies so that I swept the skies meticulously lest I missed anything truly cometary. It was 4:20 a.m. that M95, along with M96 as the first galaxies entered the FOV. Admittedly due to light pollution it was no easy detection. Only two minutes later, I caught bare sight of another galaxy, NGC 3433. It was a thrilling moment, however, simultaneously I started to feel excessively sleepy. To make matters worse, lulled by the scorcher in the daytime, I underestimated the temperature at predawn without much clothes on, wherefore I felt pretty cold when it was breezy. My concentration had to be distracted. Nevertheless, I decided to struggle against these negatives.
At 4:36 a.m. I saw an eastward satellite bursting into the FOV by a sheer increase in brightness, followed by another satellite three minutes later, brightness of 9m, but southeastward. I managed to sight a group of galaxies at around 4:46 a.m., including M105, NGC 3384, NGC 3432, and NGC 3377, amongst which M105 stood out most evidently. Subsequently I was supposed to see NGC 3338 yet failed. I must not stay up for comet hunt next time! A triplet formed by M65, M66 and NGC 3628 entered the FOV at 5:06 a.m. The former two galaxies appeared brighter than the last one, and their elongated shapes were clearly noticed. It was seven minutes later when NGC 3810 came into the FOV.
Daybreak approaching, the wind turned stronger and I started to feel sick. On arriving at the region in the proximity of NGC 4235, which I failed to spot, at the edge of the Virgo Cluster of galaxies, at about 5:27 a.m., I could not sustain myself by sheer willpower any longer but yielded to fatigue and coldness so the session was put to an end. Realizing that the current region was only within 10° away from comet 45P, I swiftly swept the scope to search for it with a shiver. Unfortunately in a hurry I swept over the region, some 40' deviated, and more ridiculously, mismatched the star pattern. When realizing the mistake, the sky had been too bright already and stars were vanishing in the background.
It should have been a copious session. Were I full of energy, I am convinced that I could have spotted more galaxies. Nonetheless, it was my first session that I have encountered so many galaxies.
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Thu,
Sep 01
Yesterday predawn I conducted a comet hunt before
the arrival of bad weather, which may well be my last hunt during the summer
vacation as the weather will keep nasty owing to remnant rainbands of tropical
cyclone Nanmadol.
The alarm woke me up at around 3:25 a.m. but I hesitated to get up for I found transparency was mediocre after looking out the window. Finally I still decided to carry out the hunt. My sweep started from ο2 Ori at 3:40 a.m. Five minutes or so later, OCL 479 entered the FOV. At 3:47 a.m. a satellite of around 8m interloped into the FOV southward. It took me another five minutes to witness a close pair of satellites both of about 6m moving northward. Only a minute late I saw another satellite with great variation in brightness moving towards northeast. Open cluster NGC 2244 entered the FOV at around 3:56 a.m., however, due to poor conditions by no means could I catch a mere hint of the Rosette nebula, but NGC 2252 and several other adjacent open clusters were noticeable. My concentration was distracted by thin clouds, and during the second sweep I realized that it had deviated far from the skies covered during the first sweep. I did not make up nevertheless lest I disordered the whole plan. Admittedly it was a disaster. At 4:20 a.m. a satellite of 8m galloped into the FOV southward. Open cluster NGC 2169 came into the FOV at 4:28 a.m., very impressive! NGC 2194 should have been obvious had the conditions been better, now only pallid. Later I failed to notice NGC 2259, another faint and tiny open cluster. At 4:35 a.m. NGC 2264 entered the FOV, yet again only the cluster visible. Seven minutes later a bright star burst into the FOV, which was anon recognized as Procyon, or α CMi. Right at 5:00 a.m. I saw a satellite of 8m with an eastward motion. The session came to end at 5:23 a.m. after 35 Gem entered the FOV since the twilight had been too bright.
I switched to MIZAR 10mm to glimpse Jupiter, poor seeing. The weather continued deteriorating and the whole sky had been rife with thin clouds by daybreak.
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Mon,
Aug 29
Eventually I was able to comet hunt this predawn!
The alarm clock woke me up at 3:25 a.m. and I quickly dragged me out of bed to
comet hunt.
I began sweeping downward from Bellatrix, namely, γ Ori at 3:38 a.m. Unluckily there was some interference from thin clouds during the first downward sweep. The lower sky I swept, the severer the influence was. Open cluster NGC 2286 was the first DSO that entered the FOV, yet it looked pale due to clouds. Later clouds dispersed and what I saw lived up to my satisfaction under such circumstances with serious influence from city lights. As the FOV was rife with stars, I had to sweep meticulously so as not to overlook any comet-like objects. I did detect numerous nebulous objects at my first sight, however, in most cases careful examinations resolved them as faint asterisms. I found it really hard to judge whether what I was seeing was a designated cluster for the stars were pretty compact. It was 4:37 a.m. that Betelgeuse entered the FOV, fabulously reddish brilliance! Five minutes later OCL 479 came into the FOV, yet since the sky was contaminated by light pollution, I failed to spot nebula Sh2-264 which covers the cluster. NGC 2244 along with several other open clusters including NGC 2252, OCL 506, OCL 517, and OCL 518 entered the FOV at 4:55 a.m. Yet again as a result of light pollution, I was not capable of detecting any hint of the Rosette Nebula. I had to conclude the session on finishing the second upward sweep after merely passing the demarcation between Orion and Monoceros at 5:25 a.m. for the reason that the twilight had already been too bright.
Before hauling back my seeker I enjoyed Jupiter for some time at 119x, however, I realized that seeing was mediocre. But rather than complain about the situation, I should be content enough, as clouds were amassed rapidly afterwards.
Sun,
Aug 14
After days of nasty weather I was able to conduct
a session of comet hunt on yesterday predawn.
I got up at 3:15 a.m. When on the roofdeck, I found that the moon was shining extravagantly and there were some cirrus clouds floating around in the sky. Consequently I decided not to observe comet C/2009 P1. I saw two meteorites which belonged to the Perseids, whose activity culminated to climax exactly around the time.
It was 3:52 a.m. that I started the session when most of the cirrus dispersed. I started the first downward sweep from the area with the same azimuth as Rigel's. Inevitably interference from the moon was so serious that it was harsh for me to catch stars faint to around 11m. M42 entered the FOV at 4:02 a.m. near the edge. A few minutes later it reentered the FOV near the center. It appeared fabulous! M43 along with NGC 1975 were faintly observable. Alongside, open cluster NGC 1981 looked pretty beautiful as well. I witnessed two meteorites fortuitously at 4:42 a.m. during a short rest to relax my neck, one of them streaked across westward in Aquarius, of about 1m, slow motion, Perseid, and the other flashed in Cassiopeia subsequently towards SWW, sporadic, fast, of about 1m. I went on to sweep. As the moon was to set, conditions turned much better than before. At 5:01 a.m. I reached M78, glamorous appearance! Right at the moment, I noticed a brilliant star rising over the eastern hill -- Siruis! Achernar was glimmering in the south. Luckily, I saw another Perseid meteorite of -1m near the border between Orion and Eridanus flashing southward at 5:04 a.m. Back to the sweep, later, I proceeded to NGC 1662, an open cluster on Orion's shield. A bright satellite of 6m intruded into the FOV at 5:07 a.m. with a westward motion. Finally I concluded the session near the border between Orion and Monoceros at 5:14 a.m. when finding the sky had been too bright already.
I stumbled across another two Perseid meteorites after the session at 5:16 a.m. and 5:20 a.m. respectively. The former shared almost the same track with the one at 5:04 a.m. but a bit fainter, of 0m. The latter flashed to the SE, of 0.5m, yet I forgot to record its position.
I also enjoyed Jupiter for some time at 119x. The image was nearly steady thanks to good seeing.
Clouds began to accumulate after I hauled my seeker back. How lucky!
Thu,
Aug 04
I got up at 2:25 a.m. this predawn for comet hunt, however, the weather
deteriorated that cirrus clouds accumulated. Initially the southern sky was
fully covered with the cirrus, yet later it expanded northward. To make matters
worse, there came some cumulus clouds from the south so that it was impossible
to observe 45P and C/2009 P1 prior to the session this time. Actually I thought
whether I should cancel the session as well, but later, I noticed that the
eastern sky was free from the cirrus, therefore, I decided to go on to sweep the
sky.
It was 3:51 a.m. that I finally started the session by sweeping from the middle point between M45 and Atik or ζ Per. Very unsatisfied, I found out that there were strong halos around bright stars owing to a layer of thin cirrus. I had to wait to see if the conditions would recover and suspended the sweep. Noticing sheer clear in the area below Auriga, I restarted the sweep from Alnath downward at 4:02 a.m. The FOV was crowded with stars. OCL 473 passed through near the edge of the FOV. Later came in Basel 4, another open cluster. Soon NGC 1893 entered the FOV, stunning appearance! I suspected whether I had captured IC 410, around the cluster there seemed to be some faint nebula, but it might be hallucination caused by the thin layer of cirrus as well in that some halos around bright stars were noticed. I would verify the reality the next time. Subsequently Open cluster NGC 2266 entered the FOV, dim stars crammed, and therefore it guised a comet at the first sight, which was followed by NGC 2331, another open cluster in Gemini. As I swept upward I met M37, like an assembly comprised of miscellanies of jewels. Unconsciously the twilight had been so bright that I was forced to conclude the session before on the way to M36 at 5:09 a.m.
I enjoyed observing Jupiter at 119x for some time after the session. Seeing was decent. Many details in NEB and SEB were resolved. NTB, NNTB, STB and SSTB appeared dim with several fine structures.
The sky turned much clearer at daybreak except the southern part.
Wed, Aug 03
Another clear predawn!
Woken by the alarm clock I got up at 2:25 a.m. The transparency was much better, at least humidity lower with less smog. Before the session I decided to observe 45P again for fear that I would lose it when it reappears in late August seen from northern hemisphere as the elongation then will be unfavorably small.
I could see it at 48x immediately by averted vision when it was trained into the FOV. It appeared very diffuse and dim. Once I spent much time exerting myself to a clearer view of it, ironically, it looked disappeared! Yet after resting awhile, I could spot it again! Had there been no strong road lights, the result might have been drastically improved. It headed southward a bit during the observation over a period of about 30-min. On Aug 02.80 UT, m1 = 10.6, Dia. = 3'.4, DC = 2/.
Later I observed C/2009 P1, which was having a closer rendezvous with M15 in the same FOV! The broad fan-shaped tail seemed obvious, spanning from approximately P.A. 160° to P.A. 205°. On Aug 02.81 UT at 30x, m1 = 7.9, Dia. = 6'.8, DC = 5/. Having completed observing C/2009 P1 at around 3:35 a.m. I re-aimed the seeker at 45P to specifically check the motion -- it looked perfectly consistent with the predicted track!
At 3:46 a.m. I began sweeping from the area degrees northwest to M45. Later open cluster NGC 1746 came into the FOV, abundant with stars! M1 soon entered the FOV at around 4:00 a.m., noticeable by averted vision. I stumbled upon a 9m satellite at 4:07 a.m. heading southward. I saw another one of 8m at 4:23 a.m. yet flying towards north. I covered numerous stunning open clusters including NGC 2175, NGC 2129, IC 2157, and M35, etc. The FOV was teemed with countless faint stars, pretty enjoyable, however, I had to slow down to sweep so as to avoid overlooking any comet-like objects lurking around. Conversely, in the meantime, it was extremely painful. A satellite of 9m moved southward through the FOV at 4:40 a.m. It was around eight minutes later when another similar one entered the FOV yet northward. At 5:05 a.m. I saw a satellite brightening up to around 2m near the culmination and heading eastward with a close encounter with Jupiter by naked eye.
The path of the Fltsatcom 4 Rocket at my site.
Wednesday, 03 August, 2011
Leaves shadow 05:03:35
Maximum altitude
05:05:09
Drops below 10° altitude 05:08:36
http://www.heavens-above.com/
Meanwhile, I noticed Achernar high in the south by naked eye, shining against the twilight and serious road lights through thin clouds with ease. Soon I felt that the sky became too bright for me to go on sweeping, so I ended the session at 5:09 a.m. when sweeping the area in the vicinity of the border between Gemini and Auriga.
Before hauling back the seeker, I glanced Jupiter at 119x. Seeing was acceptable. Coincidentally, the GRS in light red appeared evident close to the central meridian.
What a fabulous crepuscule!
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Tue, Aug 02
It turned clear this predawn, however, the
transparency was inferior to days ago.
After the alarm went off I got up at 2:25 a.m. and two minutes later when looking out of the window I suddenly caught sight of a meteorite of 1m or so from Fomalhaut and disappeared towards Diphda (aka β Cet)! It moved rather slowly in terms of a meteorite.
Prior to the predawn session I first observed comet 45P for my second time. I was able to catch it at 48x without too much exertion surprisingly as last time I did. Abdominal ache must have impeded me from gaining more photons from dim objects during last observation. Nonetheless the comet appeared quite diffuse with interference from strong city lights in the south and some smog. The southward motion was noticeable over a spell of about 20-min. On Aug 01.80 UT, m1 = 10.4, Dia. = 2'.8, DC = 3.
Later I again observed comet C/2009 P1. It was so exhilarating that the comet was having a rendezvous with M15 in the same FOV! The broad fan-shaped tail extended from the coma with fine central condensation southward. On Aug 01.81 UT at 30x, m1 = 8.0, Dia. = 6'.9, DC = 6.
A meteorite of around 0m flashed from M45 to Capella at 3:33 a.m. It was only three minutes later when another of 1m zipped in Cassiopeia to Deneb! I started sweeping a few degrees southwest to M45 at 3:36 a.m. A satellite of 9m moved into the FOV towards south at 4:27 a.m. Three minutes later, I saw a brighter one, of 7m, with a northward motion. At 4:39 a.m. I saw a satellite in orange by naked eye brightening up to the north of Betelgeuse to about 1m, slowly moving northward and finally it was hidden by the mountain. I went on to sweep and subsequently noticed that M1 entered the FOV. It was at around 4:53 a.m. when a satellite flew into the FOV with variation of brightness northward. Two minutes later another one of 4m in orange intruded in southward. The last satellite during the sweeps I saw was at 5:06 a.m. when it jogged across the FOV towards north, peaked at about 7m. Finally, I concluded the session at 5:08 a.m. when sweeping the right leg of Gemini.
I witnessed another meteorite of 1m swiftly galloping in the south towards south in Cetus at 5:16 a.m. Over excited, unfortunately I knocked down the 31.5mm eyepiece set on the chair and consequently it fell to the ground heavily with a small piece of mirror cracked at the edge. How careless and broken-hearted! But I must thank goodness that it has not shattered into pieces and the peccadillo will not bring any serious catastrophic influences towards my hunts and observations.
Fri,
Jul 29
Unexpectedly I could conduct another comet hunt
this predawn despite it had been once overcast since yesterday afternoon.
Unfortunately I did not feel well in the meantime. Perhaps my stomach had
deposited too much starch from jackfruit seeds and was suffering from slight
dyspepsia; I must have guzzled too many.
I got up at 2:25 a.m. Obviously the condition was inferior as the sky was fraught with wisps of clouds. Having received a post in the CometObs mailing list indicating that 45P/Honda-Mrkos-Pajdusakova was bright, I decided to observe 45P before the session, which was situated in northern Piscis Austrinus, high enough for me, but unluckily the area was drowned in serious light pollution nonetheless, thereby toughening my observation. I saw nothing at 30x, and after switching to MIZAR 20mm, vaguely saw something extremely dim and diffuse at the predicted position by averted vision when seeing recovered. Although endeavoring to attain a clearer view of it, I failed, so I switched to MIZAR 8mm yielding 119x. I was capable of seeing star faint to 12.5m without much difficulty, as for the comet, however, it still looked very obscure. All my efforts proved vain. Unconsciously, I have spent too much time baffling city lights to observe the comet, and it was towards 4:00 a.m. already! I must start the sweep immediately after a rough estimate yielding m1 = 12.4:, Dia. = &2', DC = 2 on Jul 28.83 UT.
I started sweeping from the area a few degrees above Aldebaran at 4:02 a.m. A satellite of 9m flied into the FOV southward at 4:13 a.m. Another satellite of around 6m in orange intruded in towards south at 4:43 a.m. It was three minutes later when lustrous Mars came into the FOV. Stars near M1 passed through simultaneously near the edge, however, unexpectedly I could not discern M1 whatever! "What's wrong? It should be bright," I thought. I introduced it specifically to the center of the FOV, still failing in detecting it. Then I noticed there was a layer of thin clouds lingering about by naked eye. It was probably the clouds that hindered me. As the twilight threatened me and clouds still prevailed I had to give up the intention of examining the thought. Anyway it seems that I need to reevaluate the influence from smog and haze, let alone clouds. I became very unsatisfied with the session. But soon my sweep had to suspend as clouds rolled in. At 4:53 a.m. I saw a bright satellite of around 3m flied eastward and soon was hidden by clouds after a close encounter with Jupiter at 4:53 a.m.
The path of the XTE at my site.
Friday, 29 July, 2011
Leaves shadow 04:50:11
Maximum altitude 04:52:17
Drops below 10° altitude 04:56:06
http://www.heavens-above.com/
Towards 5:00 a.m. having noticed some gaps between clouds in Gemini I swept there, however, I soon ended today's session at 5:04 a.m. without any hesitation for I could not stand relentless affliction from the thin clouds any longer. At 5:07 a.m., I saw the splendid waning crescent moon rising above from the mountain. The patterns of lunar maria appeared evident in the earthlit dark portion of the moon.
Generally speaking I was very discontent with the session. Furthermore, I need to learn to adjust my body to remove negative feelings as more as I can so as to obtain the best and dimmest images during comet hunts.
Thu, Jul 28
I was able to conduct comet hunt at another
superb predawn!
When I was to go to bed towards midnight, I could see the Milky Way quite apparent, meandering through Sagittarius, Aquila, and Cygnus, even though my eyes have not yet inured to darkness whatsoever. So bright was the south due to heavy lights, that Peacock (aka α Pav) still seemed very glare to naked eye. How terrific!
My alarm woke me up at 2:25 a.m. and I hauled my seeker outside as soon as possible. Wow, stars in Grus appeared bright too against the serious light pollution in the south, vividly shaped like a giant crane. Before the session I could not help but enjoyed globular cluster M15 again. Sure enough I was yet again shocked by its beauty. Then I found C/2009 P1 quickly near the cluster. Quite near to a bright star, the motion seemed manifest within couples of minutes. The two tails appeared less obvious, nevertheless visible, than yesterday due to the close encounter with the star. When later trying to select appropriate comparison stars in Comets for Windows for brightness estimate, I could not match asterisms against the chart at all. I tried again and again, and failed again and again without reason. I then suddenly noticed that I had mistakenly input C/2008 P1 (Garradd) instead of C/2009 P1 (Garradd)! How careless! Thereby I have lost ten minutes' precious time which I could have exploited for comet hunt. On Jul 27.79 UT, m1 = 8.2, Dia. = 8'.0, DC = 6.
At 3:19 a.m. I started sweeping from ξ2 Cet. An artificial satellite flied across the FOV southwestward at 3:26 a.m. Two minutes later, a meteor of about 8m dashed westward into the FOV and faded. I was a bit dismayed that I was incapable of picking up any galaxies in Eridanus and Cetus as light pollution counted. At 3:51 a.m. a satellite of 10m slowly moved in southward. Eight minutes later, another one of 9m flied in towards south. Soon I swept to Hyades, teemed with stars like varieties of jewels! Meanwhile the waning crescent moon with earthlit silhouette rose over the mountain, impressive! I came across numerous binary stars during the sweeps, some of which appeared nebulous at 30x and nonetheless were resolved into faint pairs of stars by switching to the MIZAR 20mm eyepiece. A satellite of 7m flied southward into the FOV at 4:28 a.m., followed by a fainter counterpart of 8m at 4:38 a.m. Two minutes later an 8m satellite came in yet towards north, and it was my first time to see a satellite moving northward through the seeker since the commencement of the systematic comet hunt. At 4:55 a.m. another similar one interloped into the FOV yet westward. At last I concluded the session at 5:07 a.m. when the twilight became too bright. In the meantime, Archenar was refulgent in the south!
I trained the seeker in the vicinity of ζ Tau to specifically examine whether I could see M1 or not in such conditions, and the result turned out to be astonishing -- I saw it easily by averted vision. After I switched to the 20mm eyepiece, it stood out against the twilight even more apparently. Later Mars was introduced into the FOV, and I switched to the MIZAR 8mm eyepiece, only realizing that seeing was so poor that the image kept boiling. I switched back to 30x to try to observe M78, however, the twilight has been too bright already.
It was my first time to enjoy an entirely cloud-free predawn session. What a picturesque daybreak!
Wed, Jul 27
My body sensed that the sky was so clear, that I
woke up myself at 2:30 a.m. and got up immediately after glancing outside the
window that Jupiter was blazing in the east, prior to my alarm set to go off at
3:00 a.m.
Wow, the transparency was the best so far this month! It has recovered from haze and smog. In spite of my eyes being a bit myopic, I could still see numerous faint stars in the mighty heaven. Before the predawn comet hunt session I first enjoyed globular cluster M15, so brilliant! Then I observed C/2009 P1 again. It looked enormous since the condition was superb. Two tails separately in approximately p.a. 160° and p.a. 200° were readily visible by averted vision. The former, actually the ion tail, appeared slightly longer than the latter, the dust tail. Sketch. On Jul 26.79 UT at 30x, m1 = 8.3, Dia. = 9'.4, DC = 5/.
I started comet hunt at 3:09 a.m. after the observation. As Mr. Machholz notified me that his search for my suspect at Jul 25 predawn on two consecutive predawn were negative, I thought it must be my illusion, and did not have to specifically further seek for it. Instead, I intended to sweep the sky thoroughly. I swept downward from Jupiter. Meanwhile, the waning crescent moon rose over the Mt. Ngău Thău. A bright orange meteor of around 3m flashed across the FOV northeastward in Taurus at 3:17 a.m. Later stars close to NGC 1550 came in the FOV, yet I was not able to discern the galaxy at all! It must be too dim to me under such circumstances albeit it was considered superb for my site; city lights still exert unneglectable impact to my hunt. Then a 6m or so artificial satellite flied southwestward into the FOV at 3:40 a.m. Seventeen minutes later, a fainter meteor flashed across.
When I was to reach the area near my suspect at 4:02 a.m., clouds rolled in and soon the whole sky was overcast. I had no alternative but sat on the chair and kept awaiting clouds to disperse yet in vain. Hardly could I see any stars. Occasionally gaps between clouds formed and revealed some stars in the midst of them. For recreation I used my mobile phone to check how the match between Bayern München and AC Milan was going, and I got that the Bavarian giant beat the Italian by a shoot-out.
The gaps between clouds became more and larger fianlly. At about 4:36 a.m. I saw a bright satellite of about 2m moving from Aquarius, then flickering in and out in the clouds, proceeding to Cetus and at last it was hidden in thick clouds in the east. I later knew that it was GPS 2-13 Rocket1.
The path of the GPS 2-13 Rocket1 at my site.
Wednesday, 27 July, 2011
Leaves shadow 04:35:58
Maximum altitude 04:36:47
Drops below 10° altitude 04:40:17
http://www.heavens-above.com/
Eventually at around 4:50 a.m. I could see stars in Orion shining merely above the Mt. Ngău Thău so I decided to sweep the area. I started from M42, but found the result was rather unsatisfactory due to thin clouds. I could only barely see M78 when sweeping past it. Soon I found great difficulty in seeing faint stars as the twilight became too bright. I was forced to stop the session at around 5:10 a.m. Then I found that the sky turned sheer clear without any hint of clouds whatever! Alas I was again tricked by the clouds.
Tue, Jul 26
I was able to conduct comet hunt at three
consecutive predawn from Jul 23 to Jul 25 after over a week of nasty rainy
weather, despite that by no means could the condition be referred as superb.
Jul 23
I got up at 3:15 a.m. Before starting the session, I first observed comet C/2009 P1 for the second time. Now that the waning moon was far away from the comet, it looked impressive! The broad fan shaped tail extended southward from the coma with a bright sharp central condensation. On Jul 22.83 UT at 30x, m1 = 8.4, Dia. = 7'.1, DC = 6. I started comet hunt at about 4:00 a.m. from Jupiter. At about 4:24 a.m., an orange meteor of 8m flashed across the FOV. Eight minutes later, I saw an artificial satellite of about 7m steadily moving southward. The session was ended at around 5:10 a.m. without a mere capture of a single DSO due to thin clouds as well as the moonlight. Had the ambient been better I think I should have seen NGC 1638, 1653, 1589 and 1550 during my sweeps. NGC 1637 should be bright enough, yet it was out of my sweeping paths. Before hauling back the seeker I glanced at Jupiter. Io's shadow was readily visible in Jupiter's apparent disk while Io itself eluded me. The shadow exited from the apparent disk at 5:20 a.m. or thereabouts.
I was observing Jupiter at daybreak after the
session was concluded.
Jul 24
I got up again at 3:15 a.m. for another predawn session. Likewise I observed comet C/2009 P1 again before the commencement. The coma appeared less centrally condensed but a bit larger compared to on Jul 23. The southward tail was still evident. When I attempted to measure the coma's diameter, thin clouds rolled in, therefore, I had to exert myself in measuring it as accurately as possible. Finally on Jul 23.83 UT at 30x, m1 = 8.4, Dia. = 8'.1, DC = 5. Two satellites flied across the FOV with their separate intercrossing paths when I was about to train my seeker away from the comet at 4:15 a.m. The session started at about 4:16 a.m. Unfortunately the clouds began to accumulate and soon Jupiter was gulped. Noticing that the area from Aldebaran to Capella was clear enough despite some smog, I decided to begin my sweep a few degrees south to Aldebaran. This time I attempted horizontal sweep instead of vertical one as usual. The only DSO I captured was open cluster M36. I narrowly missed M37 and M38. My sweep covered IC 410 and M1, however, both of them passed near the edge of the FOV where the image was futile. Minutes later Mars entered my FOV, which seemed totally stellar at 30x as its apparent diameter was only 4". I concluded the sweeps at 5:00 a.m. When I later checked my sky atlas, I realized that a great patch of areas have been missed during the session. As my site is situated in low latitude, horizontal sweeps seem to be inappropriate for me. Instead, horizontal sweeps cover far more areas without misses.
Jul 25
After getting up at 3:15 a.m. I first observed M15 in particular prior to C/2009 P1 again before the predawn session. The globular cluster looked so fabulous! As for the comet, the coma appeared a bit more condensed than on previous day, however, owing to the slight smog it looked smaller albeit brighter. On Jul 24.81 UT at 30x, m1 = 8.3, Dia. = 6'.5, DC = 5/. I started sweeping the sky at around 3:50 a.m. from Jupiter. Since the moon was bright, I constrained altitude of my sweeping region below 40°. When coming downwards to altitude lower than 20°, I found the LM in the FOV only around 8m, and therefore I swept altitude from 25° to 40°. At 4:25 a.m. In Taurus something suspicious that seemed very dim and diffuse came in the FOV. Then I switched to a 20mm eyepiece to have a clear check. It did seem substantial. In order to convince myself I swung my head in several different angles to view through the eyepiece, and found that it vaguely remained stable with respect to the stars in vicinity. Then it might not be illusion, I thought. Yet it was the threshold of my visibility that I still could not convince myself whatsoever; the LM only reached about 10m. I just kept monitoring it to check its motion. Indeed it seemed to move northeastward a bit. The last view of it before it lost in the swiftly brightening twilight was around 5:05 a.m., when it moved about 2' in P.A. 60° approximately. Then I quited the session.
The suspect seemed evident enough that it would be a comet! But, really? Was it still my illusion? It was so dim. I turned to Mr. Machholz for help, and he did try to look in the area at predawn on Jul 25 there in Colfax yet without anything positive. I have also asked Mr. Murakami for help, with his reply that the weather was nasty.
This predawn I was not able to comet hunt as it was overcast and pretty hazy. But now the weather seems optimistic as it is free of clouds and has recovered from haze. So perhaps I can make follow-up next predawn. Considering the moon, although waning, it moves much closer to the area than on Jul 25, which, in fact, will pose a greater challenge to me. Anyway, stay collected, and good luck to myself!
At last after monitoring the suspect, I happened to stumble upon ingress of Europa. The exact time I recorded was 5:24:56.82, however, it must be laggard than the reality since I mistakenly pressed the button of the timer and, inevitably, the stopwatch has not stopped and I had to press it for the second time!
North up and east left. I used a
digital sky chart to plot the rough positions of my suspect.
Fri, Jul 15
Clear sky!
As my body sensor told me that it was clear outside the window, I woke at 2:30 a.m. before my alarm clock was set to ring at 3:30 a.m. Despite the full moon, I quickly got up and hauled my seeker to the roofdeck. But I found that the moon was too bright, furthermore, there were some cirrus clouds expanding. A halo around Jupiter was quite obvious as a result of scattering by the cirrus. To make matters worse, masses of cumulus clouds were swiftly rolling in westward. Therefore, I decided to wait awhile until the sky turned clear.
Around 3:00 a.m., the cumulus disclosed a large patch of skies from which I was able to see bright stars in Pegasus, Aquarius and Piscis Austrinus through the cirrus. Taking the chance, I attempted to observe comet C/2009 P1, close to Biham, but was refused by the galloping cumulus again. It took me around another half an hour to see a somewhat clear sky without much cumulus. I quickly trained my seeker to η Aqr, hopped northward to π Aqr and went on, soon the comet was introduced into the FOV near 30 Peg.
In spite of the blurred moon whose brightness was mollified by the cirrus, I found the comet would have been a threshold for me to spot as an unknown object during the sweeps under such poor circumstances. Nonetheless, as a known one, it still appeared obvious, with a manifest central condensation. The coma seems elongated towards WSW. On Jul 14.84 UT at 30x, m1 = 8.5, Dia. = 6'.0, DC = 5. During the spell of about 20-minute, its motion toward northwestward was readily noticeable to me. It was my first time to observe the comet.
Immediately after finishing observing C/2009 P1 at 4:05 a.m., I started sweeping from Jupiter through the opaque cirrus.
Needless to say, the result was very unsatisfactory; the faintest stars I could see were only dim to around 10m. Yet the cumulus clouds rolled in again and eclipsed all the stars no sooner than around 4:25 a.m. when I was sweeping Eridanus. The cirrus was thickening as well and soon Jupiter disappeared! Noticing that Perseus and northern region were free from thick cirrus, I trained my seeker to Algol from which I started another sweep. Unfortunately I was again clouded out only around five minutes later!
Ten minutes later, cumulus rolled out and revealt Jupiter again. Clouds in SE and E were decreasing in general. So I continued the sweep from the sky where I was forced to end during the first sweep. I swept downward until meeting the woods on the Mt. Ngău Thău, moved northward, and swept upward carefully. Cirrus exerted heavier impacts upon my hunt that I could only see stars faint to around 9m now! Regardless, I went on sweeping upwards until arriving alt. = 40°, again moved horizontally northward a bit and started another downward sweep. At 4:50 a.m. or thereabouts, a 7m satellite in orange moved across the FOV southward. Now the clouds became fewer and fewer! Aldebaran blazed high in the east. If only the clouds had decreased earlier! Meanwhile, I felt I must conclude my sweep at around 5:10 a.m. when I swept to near 47 Tau, for the twilight became so bright that I felt some difficulty in telling a star faint to 8m.5.
Before hauling back my seeker, I glimpsed Jupiter at 119x. The seeing was excellent! At 5:20 a.m., I completed the observation.
It was a pity that I have not picked up any DSOs, but given the situation, it was quite reasonable. Despite that I covered southern Aries, northern Cetus, northern Eridanus, eastern Orion, and southern Taurus where there abounds with galaxies, however, the majority of them are very faint. Had there been no clouds, I would have been able to pick up some bright galaxies like 10m.8 NGC 1637 in Eridanus during the sweeps.
Anyway, I enjoyed comet hunt very much, as it does bring me countless pleasure!
Thu,
Jul 14
There were some gaps among
clouds so I decided to get up to comet hunt at predawn to try my luck. However,
I did not feel well and suffered from diarrhea when was to go to bed.
Nevertheless, my alarm clock went off at 3:00 a.m. and I did manage to get up to
glimpse outside the window. Unluckily, it was overcast again without any stars
in the sky seen. Recalling that I had seen the brightly moonlit floor before I
fell into sleep, so I intended to get up again half an hour later, however, I
failed -- when I was awake, it was already morning! The sunlight pierced through
the window sharply. Despite that it might not be totally clear, it must have
many great patches of gaps in the midst of clouds that would have enabled me to
conduct comet hunt at predawn. How silly I am! I am a profligate who always
squandering so much precious time. I am bound to achieve nothing if I continue
this way!
Drawing a lesson from this, I will get up immediately after the alarm rings, regardless of what the weather is like. Once it happens to be overcast, I will sit up to wait until clear skies appear and go to comet hunt, otherwise I will keep waiting unless twilight becomes so bright that there is no use comet hunting any longer.
Mon, Jul 11
As a result from a broad area
of low pressure, I am afraid that my comet hunt will be forced to cease in this
lunation as the weather is predicted to be nasty in the coming days. Actually
last night a fierce thunderstorm touched down where I was; a rainfall during a
span within less than three hours around my site had a record of about 50
millimeters.
MTSAT visible
image. A green arrow indicates the location of my city Guangzhou.
Sat, Jul 09
Oops... I failed to get up
this predawn. Although before my alarm clock rang at 2:30 a.m., I had once waken
and taken a squint outside the window, however, the sky appeared excessively
light polluted mainly attributed to haze. In fact I heard the alarm ringing but
quickly turned it off; I felt very tired, as I have not recovered from fatigue
yet. I intended to get up to specifically observe C/2009 P1 once the condition
was thus unfavorable in which comet hunt would be meaningless.
I have lost another chance! As the moon is steadily moving easterward, my search time at predawn will become more and more limited this month.
Fri,
Jul 08
Taking Don Machholz's suggestion,
I begin my hunt for comet from this predawn on.
Yesterday I was back to Guangzhou from Wuhan where my university is, as my summer vacation is on. In the evening my uncle drove me to my maternal grandparents' house in northern suburb.
I set the alarm clock at 2:30 a.m. but was reluctant to get up immediately, for one thing I felt greatly tired due to insufficient sleeps during these days, for another the sky did not look quite clear through the window -- there were many clouds with some gaps from which I could see Fomalhaut shining high in the south. But finally I managed to pull myself out of bed at around 2:50 a.m. as Don's advice that I should go to hunt for comet whenever I can came to my mind boomingly.
I hauled my 8" seeker out to the roofdeck. Looking overhead, I saw most of the clouds cleared out, revealing Pegasus close to the zenith. Jupiter was gleaming in the east above the Ngău Thău Mount not far from my site. Around the zenith, the NELM was only about 5m; evidently the new bright roadlights had great impact upon my site what was used to be a superb dark site that once enabled me to enjoy stargazing couples of years ago, let alone in my childhood!
I first used Jupiter's satellites to help collimating my seeker, and found that it remained intact during the days when I was outside so there was no need collimating the mirrors.
For fear of threats from the clouds, I decided to give up the observation of comet C/2009 P1 (Garradd). Instead, I must start comet hunt as soon as possible, therefore, I started sweeping from Markab at around 3:25 a.m. I dragged my seeker slowly downward trying to pick up every possible fuzzy object in my way. However, I did not detect any truly diffuse objects. I once came across one, but later resolved them as an asterism in Pisces that consists of several faint stars of about 11m. At about 3:40 a.m., a meteorite of around 8m swiftly flashed across the FOV. When I swept to the northwest region of Cetus about thirty minutes later, clouds rolled in so I had to wait until it turned clear again, however, the clouds increased without any hint of clear. Yet many of other areas were clear enough without too much interference from clouds, therefore, I had to sweep these regions.
I trained my seeker to sweep near Jupiter for some time, but clouds swallowed the FOV agilely again! The clouds seemed to accumulate in the east and became thicker. Looking back Cetus, clear! But after a scrutiny revealing that there were some thin clouds in the southern Cetus, while Pegasus now totally lay in the zenith without any clouds, I decided to sweep again from Pegasus, but this time, to be more particularly, from Algenib, rather than Markab. I pulled my seeker sweeping downward carefully again. During the sweep for several times clouds rolled in but all finally moved out the FOV. Unfotuitously when NGC 467, 470 and 474 were to be introduced into the FOV, the clouds entirely gulped the stars. But noticing fewer clouds in the south, and twilight was approaching as well, I kept sweeping downward. Later Mira came in the FOV, which appeared quite faint compared to its maximum brightness, only about 9m at a rough estimate. I finally came to Eridanus where my view was blocked by the eucalypt woods on the mount, so I trained my seeker northward a bit and swept upward. Unluckily, soon clouds expanded again and the FOV was covered. I waited and waited, but the clouds refused to move out. Jupiter was eclipsed too. Without alternative I had to give up continue sweeping this region.
Alas, the twilight has already begun without any consciousness! Now almost the whole sky was teemed with clouds, except for a tiny region low in the ENE above the Ngău Thău Mount, where I could see Aldebaran and Capella. Before expansion of the clouds, I clearly saw Pleiades. I trained my seeker to this region and started another sweep, which only lasted for about fifteen minutes. Interestingly, around 4:50 a.m., an artificial satellite of 8m glided across the FOV southward, closely chased by another satellite with almost the same magnitude.
Finally as the twilight brightened, I had to stop the sweep at 5:00 a.m. before covering the area where 27P/Crommelin was. Prior to pulling back the seeker, I glimpsed at Jupiter through an NR 8mm eyepiece, yielding a power of 119x. Obviously now the SEB has been revival in that it appeared quite noticeable. About three degrees south to the Jupiter, I noticed a group of bright stars vividly shape like a warping serpent. The sky abounds with multifarious of animations!
Frankly I was unsatisfied with the session this predawn since I failed to pick up any DSOs during the sweeps. Apart from this, I have sacrificed the precious time to observe C/2009 P1 (Garradd) and 27P as well; I had no other choice unless there had been a lot of plenty free time. Taking the nasty weather into consideration, I felt somewhat soothed. Undoubtedly I need much more practice before getting familiar with comet hunt. Anyway, I have set out to pursue my dream.
Sun,
May 01
I managed to observe comet C/2011 C1 (McNaught) for another four
times through the 21.0-cm Cassegrain reflector at predawn on Apr 19, Apr 24,
Apr 25, and Apr 26. The details are listed as follows.
Merely before the midnight on 25th, I observed and sketched Saturn again through the 21.0-cm reflector and a OR. 6mm eyepiece. The seeing meliorated during the observation session, started at around 23:36, averagely around III Antoniadi scale, II Antoniadi at best. The Cassini Division appears obvious. Miraculously I was able to discern a faint spoke over the inner Ring B. Meanwhile, the Encke Minima eluded me mainly attributable to insufficient tilt degree, let alone Encke Division. The NPR appears greenish-brown, the NTrZ and the EZ appear bright, while the NEB appears dusky, with two darker features separately around the central meridian. In the southern hemisphere, the SEB appears somewhat brighter than the SPR. The session ended at about 23:55, whereafter seeing drastically deteriorating as winds intensified.
On 25th evening, I also visually observed recurrent nova T Pyxidis, which has been discovered in outburst since December 7, 1966, almost 45 years. By exploiting two comparison stars in the vicinity, I obtained its visual magnitude at 7.6 on 25.57639 UT.
Judging from the plots generated by the Light Curve Generator in AAVSO, T Pyx is experiencing a slight decline in brightness. But I am convinced that, weather and time permitting, I will have more chances to observe it.
It is noticeable that, before observing the recurrent nova, at around 19:56, I haphazard witnessed a verdant fireball of -3m slowly moving from approximate ten degrees higher than Polaris, lasting for ~1s, vanishing around the spot of Az. ~ 345°, Alt. ~ 20°. No sound was audible, nor could I see its fragments or companions.
Furthermore, I was capable of observing several DSOs, including globular clusters M3, M5, and M13, neblula M57, NGC 6543 (or more well-known as the Cat's Eye Nebula), and galaxies M51 along with its companion NGC 5195, M81, M83, M87, and M104 (the Sombrero Galaxy). Yet I failed to catch any mere hint of Omega Centauri due to its low altitude stained with severer city lights. I was impressed by NGC 6543, which appears unexpectedly bright through a 25mm eyepiece.
 |
Sun,
Apr 03
It had been long since my last observations of comet(s) on Dec 18
predawn, when I managed to observe comet 103P/Hartley, and the
comet-shaped Main Belt Asteroid, (596) Scheila, owing to many factors,
such as scarcity of bright comets during this spell, nasty weather, hectic
homework, preparation for GRE, and so forth. But now the situation is turning
somewhat better -- at least several comets have been bright enough to come into
my capacity through my equipment.
It was so clear last Monday evening that I could not resist the temptation but went to Mt. Guizi in order to visually observe comets. First I enjoyed Saturn through the 21.0-cm Takahashi Mewlon Cassegrain at 242x. Seeing was variable, for some of the time it was estimated to be at II Antoniadi at best, for the other it was at IV Antoniadi. I could see many detailed features along NTropZ and NEB, whose boundaries are indented.
I started to observe comet 29P/Schwassmann-Wachmann after midnight. After having utterly adapted to darkness, I managed to detect it as a ghostly glimmering blotch at the predicted position when seeing turned better occassionally, accompanied by numerous faint stars in the FOV by averted vision. By repetitively keeping track of it uncontinually, I substantiated that it was indeed the comet, as the spot has shifted during a period of an hour or thereabouts. Notwithstanding interference from city lights, it seems not that tiny; the coma seems uniformly circular with a small eminent central condensation. On Mar 28.74 UT at 134x (dubious power, to be verified by experiment the other day), m1 = 12.2, Dia. = 2'.7, DC = 5.
Later at about 4:00 am, I turned the scope to observe another comet C/2011 C1 (McNaught). However, unfortuitously, aside from city lights, the old moon lies quite close to the comet, only approximately 11° away, which evidently induced interference to my observation. Nevertheless, I succeeded in my effort to catch sight of the comet as a diffuse object with slightly condensed toward central condensation in the midst of many faint stars. Again I tracked the comet and found that it moves rapidly with respect to the background stars -- its motion over a 30-min period is manifest enough. Unluckily I spent too much time in checking its motion, therefore, when I started to make estimate, astronomical twilight has begun and thus might have tainted my results more or less. On Mar 28.89 UT at 81x, m1 = 10.1, Dia. = 4', DC = 3.
