Sunday, December 25, 2011

Lovejoy survives perigee - and now plays mini-Ikeya-Seki for Oz et al.

Defying practically all predictions, comet P/2011 W3 (Lovejoy) not only survived perihelion with ease but then formed a long and narrow tail that is well placed for the S. hemisphere now and resembles a small copy of that greatest sungrazer of the 20th century, Ikeya-Seki and giving it a quite good rank among all fine comets. Some picture collections of this amazing comet by V. Tabur, R. McNaught and B. Armstead, protocols of its behavior after and before perihelion, a calculation if its period (roughly 800 years), the lightcurve (that peaked at ~ -4 mag.), various notes in English, French and German, numerous satellite clips around perihelion (also w/an overly dramatic score and as a ballad ...), the geometries for SOHO and STEREO A (more) and various pictures (earlier).

Selected pictures of Dec. 26 local time (dito), Dec. 25 (dito, dito), Dec. 24 (dito, dito, dito, dito, dito, dito, dito, dito, dito, video, another), Dec. 23 (details, more, more, dito, details, more, dito, more, Dec. 22 from the ISS and from the ground (details, more, cloudy, in motion, more), Dec. 21 from the ISS (more & video) and from the ground (dito, dito, dito, dito, dito, details, dito, dito, dito), Dec. 20, Dec. 19 from the ground (earlier) and STEREO A, Dec. 18 from the ground and STEREO A (more), Dec. 17 from the ground (alt., more, explained, dito) and STEREO A (later), Dec. 16/17 LASCO C3 animation, Dec. 14-17 LASCO C3 montage and animation, Dec. 16 LASCO C2 (animation), LASCO C3 and STEREO A, Dec. 15 SDO (alt., alt.) and LASCO C3, Dec. 11 STEREO B and Dec. 4 ground-based.

Visual reports of Dec. 25 (a drawing), Dec. 24 (more), Dec. 23, Dec. 20, Dec. 17 and Dec. 16. Press releases and space agency notes of Dec. 24, Dec. 22, Dec. 16 (more and more), Dec. 15, Dec. 14 and various dates. And news, blog and mailing list coverage of Dec. 25, Dec. 24 (dito), Dec. 23 (dito, dito, dito), Dec. 22 (dito, dito, dito, dito, dito, dito, dito), Dec. 19 (dito), Dec. 18 (dito), Dec. 17 (dito, dito, dito, dito, dito), Dec. 16 (dito, dito, dito, dito, dito, dito, dito, dito, dito), Dec. 15 (dito, dito, dito, dito, more), Dec. 13, Dec. 6 and Dec. 5. • In other small bodies news a big paper on active asteroids (more), a bolide over Canada that may have dropped meteorites (more, more, more, more, more and more), a fine Geminids peak mit a peak ZHR of 200 (picture, another, yet another, composite, more, preview, side effect ...), a preview of the 2012 Quadrantids and a paper on the 2011 Draconids, observed from a plane.

The last total lunar eclipse in 3 years on Dec. 10 was widely observed, with yours truly in an ideal spot in India: this was mentioned in international reports here, here and here. Numerous pictures, reports and websites about this lunar eclipse from around the world can be found e.g. here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here (the most unusual report - from the Nordkapp!), here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here and here (anyone volunteering to sort them by country or longitude? :-) - also a preview of what the LRO planned and a bizarre headline ...

In other news insights into the chemistry of Pluto, an apparent detection of the rings of Uranus by an amateur (more), recent hi-res Jupiters, all planets in the sky now (here they are), Moon, Venus & Mercury on Nov. 27, space weather visuals, insights, lunar effects and prediction attempts - and a hectic aurora movie. • Insights into the progenitor of SN 2011fe (more, more, more, more, more, more and more press releases and coverage here and hier). • Finally the reentry of a Soyuz upper stage was widely observed in Central Europe yesterday (official word, more and more analysis, further stories here and here and more witness reports) - and an article (p.10-11) on imaging satellites.

Saturday, December 3, 2011

First ground-based discovery of a Kreutz comet since 1970 - by an Aussie amateur!

Many hundreds of sun-grazing comets of the Kreutz family have been found in recent decades by Sun-watching satellites with their coronagraph cameras when they were already very close to the Sun - but with C/2011 W3 (Lovejoy) it was different! For the first time since 1970 this Kreutz comet was discovered weeks before perihelion: by Australian amateur Terry Lovejoy who incidentally also was a pioneer in sungrazer detection in SOHO images. Already before it had a proper number, the object's orbit hinted at a sungrazer, and the 1st 'official' orbit has Lovejoy reach perihelion exactly on Dec. 16 at 0:00 UTC at a solar center distance of 0.00589 AU - that means a mere 140,000 km above the solar photosphere. While ground-discovered Kreutz comets have often become great sky shows, it's doubtful that C/2011 W3 - still very faint: pictures here and here (scroll down) - will survive its brush with the Sun and follow the tradition. Then again one never knows - and there should at least be a fine performance when Lovejoy enters the FOV of SOHO's coronagraphs on Dec. 12.

In other comet news there was yet another amateur discovery - and the first from African soil in some time: comet P/2011 W2 (Rinner), now celebrated in France and elsewhere but always staying faint like now. • Comet Garradd remains a dud for visual observers and a beauty for photographers as pictures from Nov. 28 (more!), Nov. 27, Nov. 25. (looks like Halley in April 1986, no?), Nov. 22, Nov. 20, Nov. 19 (more), Nov. 15 and Oct. 28 show; also comets Hill and P/2011 UH55. • The Leonids of 2011 reached only a ZHR of 20, as expected, but produced nice fireballs as seen e.g. here, here and here; also a long report about the Draconids 2011 over Egypt. • And talking about things hitting the Earth - or not - news from 65 Myr ago, 200 Myr ago and 252 Myr ago (more and mehr).

Yet more results re. NEO 2005 YU55 keep trickling in: joint lightcurves (scroll down), a parallax demonstration, the results from Herschel [Deutsch] (some numbers), the Arecibo radar 'images' and processed - kind of - Goldstone data (plus a summary of earlier stuff). • Also a successful observation of an occultation by Kalliope and all chords, a paper on Themis et al. and a press release on a student NEO discovery. • Some fine Jupiter images of Nov. 25, Nov. 21 (amazing; more), Nov. 16, Nov. 12 and Oct. 21, a weird animation from here. • Plus some constellations: Moon & Venus on Nov. 27 and Nov. 26 (also an attempt from Austria), Moon & Saturn on Nov. 23 and Venus & Mercury on Nov. 13.

There was a partial solar eclipse on Nov. 25 which could be observed only in the deepest South: some pictures & stories from South Africa (more) and Antarctica (more), collections here, here, here and here, the funny view from Hinode which saw three eclipses, coverage here, here (more) and here and previews here, here, here and here. • Also a podcast & transcript on upcoming solar eclipse science and stories on the future of the solar cycle, the shape of the solar wind [Deutsch], new Cluster observations (more), solar monitoring by the Proba 2 spacecraft and progress in solar storm forecasting.

In other news SN 2011dh in M 51 is still producing science headlines, like on the pre-explosion variability of the progenitor and early radio interferometry observations of the remnant; the latter paper and many more on 2011dh had already been discussed here (and the former one is here). • An amateur apparently captured the dust disk of Beta Pic with just a 10". • A nice 13-min. movie on Namibia's skies, artistic photographs of star trails and experiences on a ship hunting the Aurora off Norway. • The reentry of the latest Soyuz filmed from the ISS (1st minute), Chinese amateurs watching Tiangong, David Levy's logs online, TGFs and the future of UTC after the likely end of the leap second. • Among the sky events in December the lunar eclipse on the 10th dominates: more previews here, here, here, here and here, with a call for observations.

Sunday, November 13, 2011

Earth visit of big, dark asteroid widely observed with all means

Only a fraction of the scientific data recorded with everything from big radar dishes to a 10-meter telescope with adaptive optics to the large IR satellite Herschel have been reported yet, but it can already be stated 2005 YU55 will probably be the best studied minor planet (not directly visited by a spacecraft) ever: a live-blog tracked the news from Nov. 6 til 10 and has many pictures, videos and links; since wrapping I've seen more videos here, here, here, here and here - also an improved radar movie, a late wire story and a simulation of what would have happened had YU55 impacted Earth.

In other planetary system news a long press release on a meteorite found by a Missouri farmer - a 17-kilogram pallasite! - and pictures of a bright Dutch bolide of Nov. 12. • Another - very faint - detection of (ex-)Elenin on Nov. 8, a great picture of comet Garradd of Oct. 30 - and C/2010 S1 (LINEAR) approaching the Bubble Nebula on Nov. 12. • How Venus & Mercury were easy - when you were in Australia. • Some selected Jupiter images of Nov. 13, Nov. 6 (more) and Oct. 23 - and a breathtaking animation of Jupiter images taken with the Pic du Midi 1 m telescope in October!

The huge sunspot group 1339 is almost history after - despite breathless articles like here, here and here - crossing the solar disk w/o further incidents: some selected pictures of a fine prominence today, the white and H-Alpha Sun (more) and a huge filament on Nov. 12, the white Sun full of spots on Nov. 11, a spotted sunrise on Nov. 10, the full disk + detail on Nov. 9, the group at the center on Nov. 8, the group and a spotty sunset (another one = an APOD) on Nov. 7, the full disk, detail, H-Alpha and spotty sunset on Nov. 6, detailled drawings of Nov. 5 (also a photo) of Nov.5 and earlier drawings of AR 1339. • Plus no superflares (more), strange jumping sundogs - and the likely end of the leap second.

Sunday, November 6, 2011

Biggest sunspot group in years crossing the disk; already one X flare seen

The new activity region 1339 - a full-disk view of today and another close-up - is now crackling with M-class flares as it approaches the center of the disk. Just after arriving around the limb it had fired off an X-class flare ("Ein Flare der ...") on Nov. 3 that made some headlines but not another one - thus geophysical effects of AR 1339 have so far been absent. • Also some truly great aurora images (in the picture stream, both directions), the anatomy of a geomagnetic storm, a detailled report and 3 videos from the German outburst of Oct. 24/25 (also a Canadian view) and a solar cycle primer. Plus a paper on the solar corona and how and why visual and photographic impressions differ so much.

Elsewhere in the Galaxy the Epsilon Aurigae eclipse is not completely over, with lingering spectroscopic effects; also the 9th campaign newsletter. And some recent images of M 101 and its fading supernovae; some science results (also about the one in M 51) can be found linked here. • Back in the solar system Venus & Mercury on Nov. 5th and Oct. 27, Jupiter's Io covering its shadow and unusual events around opposition (more, more and more). • An amateur non-detection (but great 2006 pics!) of the bright Uranus spot (more and more). • The full paper on Eris' diameter, a press release and yet more stories here, here and here.

The most unusual event of the month - with few other highlights - is the close approach of the 400-meter asteroid 2005 YU55 which already being tracked with radar by Goldstone, supporting planned Herschel observations: more previews of the hard-to-observe event here, here, here, here (earlier), here, here, here, here, here, here, here, here and here. Also recordings of two related chats here and here and articles in German hier, hier and here, plus more media reax. • Also La Palma crossing M 31 again, the stones from 2008 TC3 and a CBET on the Draconids, a rare visual observation and images of Nov. 1 (animated) and Oct. 27 (processed and explained), a looong rant about and Indonesian coverage of ex-Elenin - and Garradd on Oct. 30.

Thursday, October 27, 2011

Bright spot emerges on Uranus - can amateurs track it (and thus help Hubble)?

Observations with one of the Gemini 8-m telescopes show a very bright spot that has suddenly appeared on Uranus and is at least 3 times brighter than the remote planet's disk: "If this is a convectively driven white feature it may evolve to larger size and brighter appearance on the next few days," says an unusual alert message distributed via The Astronomer network earlier today. Moreover amateur images of Uranus are now considered "essential to study this feature and its precise drift rate to assist possible observation with other highly-priority telescopes such as the HST." Uranus subtends 3.7" in the sky, and the bright cloud feature is at least 0.33 arc seconds making this feature potentially accessible to relatively modest telescopes. On 2011 October 26 at 08:06 UTC when the linked picture was taken the spot was at 323° west longitude and 22.5° north; the current estimate for the rotation period of this feature is 17.24 hours. • A slightly easier target is Jupiter, now in opposition: selected images from Oct. 24 (46 cm scope), Oct. 22 (20 cm - animation), Oct. 13 (1 meter), Oct. 3 (25 cm) and Sep. 26 (23 cm).

Comet Elenin has been recovered after all, now that the Moon is out of the way, but only as an extremely diffuse dust cloud with not one individual fragment brighter than 22.5 mag.: reports on the hunt and what one can see (or rather image) from Oct. 25, Oct 24 (more), Oct. 23 (more), Oct. 21 and Oct. 15, pictures of Oct. 24, Oct. 23 (more, more and with just 8 cm aperture), Oct. 22 (more), Oct. 21 (negative), Oct. 15 (positive after looking hard) and Oct. 14 (negative), another claimed visual observation (why such a small 'coma' size?), a long essay on visual comet observing - and a very stupid NASA press release asking for Elenin to "be forgotten". Rather forget such dumb advice and observe the most unusual ... thing that Elenin has turned into while it's still possible (it's now receding from both Sun and Earth).

In other comet news the first Jupiter Trojan comet has been found - and Bressi may be interesting. • Pictures of Honda-Mrkos-Pajdusakova from Oct. 15, Oct. 7 and Sep. 30 (with a mountain) and Garradd - which now has a nice plasma tail as well! - of Oct. 23 (more), Oct. 17 (more), Oct. 15 (more) and Oct. 14 (more). • Another - smaller - comet hit the Sun on Oct. 19 (earlier, still earlier), a video on the Oct. 1 case and 5 years of comets observed by the STEREO mission. • The physics of impacts on Earth, an observing guide for and JPL Release about coming NEO 2005 YU55, an asteroid crossing M 31 (movie) - where it was mistaken for a nova! - and a Subaru Release about Scheila's outburst.

In other solar system news Venus and Mercury low in the evening sky on Oct. 24 (USA) and Oct. 22 (Australia and - w/o Mercury - Austria) - the new evening apparition of Venus will end with the solar transit next June! • The equal diameters of Eris & Pluto also discussed here, here, here, here, hier, hier, hier and earlier here. • The Orionids delivered a nice show, only a maximum ZHR of 50, but it looked great for some (another and another night); also an all-sky sum image, a spectrum (more) and a picture. • From the Draconids a detailled story with pictures from the NE German campaign, another video from the NL, observations by ESA, a German video (AVIS2), the radiant from 6 video cameras and a Spanish composite image and report. • Also a night with 5 showers, no evidence for interstellar meteoroids and a German fireball. • This month's full moon was the smallest of the year: a comparision with the biggest one (alt.) and a list of big ones.

In other news there was an aurora outburst Oct. 24/25 over e.g. Germany and the U.S.: a great German timelapse video, a fine gallery, pictures from all over Germany, Alabama (w/video) and N. Germany and coverage here, here, here, here and here. The CME that caused it was launched on Oct. 22 as was another one that headed towards Mars; there was a lot to see on the Sun that day. • Weird NLC-like looking clouds may have been caused by the 1st S. American Soyuz launch, and a picture of Spektr R deep in space. • A German press release on that rare triple rainbow (with the full paper) - and a double rainbow with a stupid caption (as if it stretches from one place to another). • And then there was a bizarre paper on things in front of the Sun in 1883 which some rightly attacked (mehr) but others found at least intriguing. And as if ordered: a mystery crossing the solar disk just this month ...

Wednesday, October 12, 2011

Comet Elenin gone for good (though some still claim detections, even sightings)

With this negative report, setting tough upper limits on the brightness of whatever may be left of much-expected/hyped/feared comet C/2009 X1 (Elenin) on Oct. 9 and 10 the hunt seemed to be over - yet there are claims that the STEREO satellites can still see it (they probably did in the 2nd half of September; see also this and this tweet) and even of a visual sighting right when the big scopes saw exactly nothing. How could that be? A major mystery right now that puzzles even leading comet gurus ... anyway, this alleged detection of Elenin by Elenin himself (also reported e.g. here [earlier] and here) was probably just noise. Now the Moon is spoiling the view in the morning where the comet - or rather its theoretical positing - is quickly climbing higher; by about Oct. 23 deep observations will again be possible and should settle the issue for good.

In other comet news the plasma tail of comet H-M-P continued to amaze: big picture collection and shots of Oct. 11, Oct. 6 (wider), Oct. 5, Oct. 4, Oct. 3 (b/w), Oct. 2 and Oct. 1. • Comet Garradd on Oct. 10, Oct. 3 and Sep. 29 and the comets C/2011 P1 (McNaught) and C/2011 S2 (Kowalski). • The fate of the Great Kreutz Comet of 2011 - and some funny sungrazer/CME statistics (not proving much yet). • The outburst of Scheila modelled - and modelled again. • The Draconids outburst was covered by a huge live-blog with numerous links; a nice persistent train and meteor. • A meteorite hit a house near Paris in the summer (more, more, mehr), and the complex origin of 2008 TC3 and its meteorites.

In other small bodies news a NEO discovery by amateurs 'working for' ESA's Awareness, a call for observations for an upcoming NEO passage, observations of a past one - and more astrometry of Apophis (strangely missing from the JPL analysis of impact risk). • The moons of Minerva (more and more) and an extremely tilted KBO contact binary (more). • The star occultation's outcome was that the diameter of Eris is just like Pluto's (also covered here and here - after some some embargo problems that suddenly evaporated) - and the temperatures on Makemake.

In other news Jupiter on Aug. 18 til Oct. 4, Oct. 3, Oct. 2/3 (map) and Oct. 2 (more). • Solar eclipses causing wakes in the atmosphere. • The AAVSO is 100 (from there a 100a of SS Cyg video from this source) and private lightcurves of the SN in M 101. • A quadruple rainbow makes headlines here, here, here, here and here. • A story about Damian Peach, the solar system photographer. • Observing NanoSail D in hi-res. • A summary brochure of the Decadal Survey. • The world's largest clock dial in Mekka. • And the smallest full moon was obviously smaller than others (more and more) - don't let them tell you that the effect isn't clear to the naked eye!

Sunday, October 2, 2011

Best aurora of the cycle yet caused by impressive sunspot group

Solar activity is now clearly on the rise, as are space weather effects right here on Earth - and the Activity Regipn 1302 which crossed the disk in recent days (more pictures here, here and here) drove the message home: mainly with a major flare on Sep. 24 that caused a strong geomagnetic storm on Sep. 26 (also discussed here, here, here, here, here and elsewhere). And this, in turn, led to the best aurora of the current cycle, beating the brief August show: some summaries are here (incl. a crappy picture by yours truly; the aurora is the reddish glow on the right), here (more), hier (table) and hier. Further pictures, videos and reports from NRW in Germany (best pix from Bonn) and elsewhere in Germany (more, more, more and more), Austria, Norway (more, more and more), the Netherlands (more), Slovenia, Sweden, Finland, the Outer Hebrides, the U.K. (more, more) and the U.S. (more). There had been another flare on Sep. 22 (more, more and a CME series Sep. 18/9; also the 'secret lives' of flares and a timelapse aurora video from Finland.

Elsewhere in the solar system IR Keck images of Neptune and Uranus (more and more), amateur images of Jupiter of Oct. 1, Sep. 26 (also w/8" - and structure on Ganymede!) and Sep. 22, and Mars on Sep. 26. • NEOWISE has revised the statistics of NEOs (alt., ident.; coverage here, here, here, here and hier) and the history of the Chicxulub impactor (covered here, here, here, here, hier and hier); the latter's role in the dino death is still under debate, by the way. • Among comets there were a bright Kreutz, lots of structure in 45P/H-M-P's tail & Jupiter near-crash (H-M-P today), new main belt comet P/2010 R2 (La Sagra), further fragmentation in 213P/van Ness (more, more), new comet Gibbs, no LASCO sighting of damaged Elenin and a naked-eye sighting of Garradd (which did not fade afterwards); also picture of Sep.30, Sep. 26(!), Sep. 24 and Sep. 21.

Sky highlights in October - see overview articles here, hier and here - include:
  • Oct. 1-2: Mars passes Praesepe, the star cluster.

  • Oct. 8 (around 20:00 UTC): Possible outburst of the Draconids (more, more), but the predictions remain confusing - and the event coincides with Observe the Moon Night which is not a good night for meteor watching ...

  • Oct. 21-22: Peak of the Orionids; less lunar interference than with the Draconids, so worth a look.

  • Oct. 27/8: Conjunction of Moon, Venus and Mercury low in the evening, invisible in higher N latitudes.

  • Oct. 29: Jupiter in opposition with -2.9 mag.; it's awfully bright already now (closest to Earth on Oct. 27 already).
Meanwhile the supernova in M 101 has faded a full magnitude from the peak, to 10.9 mag. - and the hunt is on for Snoopy from the unsung Apollo 10 mission ...

Friday, September 16, 2011

After Elenin's rapid decay: will anything be seen again

when the comet or rather its debris cloud - now impossible to observe from the ground - will make an appearance in the field of view of SOHO's coronagraph LASCO 3 a week from now? Despite a brightness enhancement of its dust due to forward scattering - the comet is practically between us and the Sun - the SOHO comet experts are pessimistic, given the apparently complete decay of Elenin beginning August 20. The most diligent observer of its fate was an Australian: His pictures document the dramatic change of the comet's appearance as well as its sudden break in the light curve - by September 14 it had fallen below 10th magnitude again. The comet had also been followed by the STEREO spacecraft (images of Sep. 10 [enhanced], Aug. 25, Aug. 23 and Aug. 21), another Australian and radio astronomers; stories about the decay also here, here (earlier), here, here (earlier), hier, hier and hier.

In other comet news van Ness may also have fragmented again (more, more). • Garrad continues to be tracked widely as the comet passes numerous deep sky objects: many pictures, esp. from the 'coathanger' visit and selected images of Sep. 10 (more), Sep. 7, Sep. 6, Sep. 3 (more, more, more and more), Sep. 2 (more, more and more), Aug. 29, Aug. 28, Aug. 27 (more and more), Aug. 26 (more, more, more, more, more, more, more and more) and Aug. 25. • Also new comets from Russia (media report), PanSTARRS and SWAN.

In further small bodies news thoughts on color diversity in the Kuiper Belt and tectonics on and oceans in icy worlds. • Hailing the outcome of the Antiope occultation. • Everyone wants a satellite to hunt for NEOs. • A major bolide over the SW U.S. on Sep. 14: video & analysis, NASA statement (alt.) and early stories here, here, here, here and here; also an earlier bolide over Atlanta (more) - and details about the meteorite rain in Kenya.

On the Sun a series of flares kept observers on edge: there were X flares on Sep. 7 (video, pictures, story, follow-up, aurorae, pictures) and Sep. 6 (video, story, more and an M flare on Sep. 5. Also insights into late flare phases (more, more, more, more and mehr), fast substorms, linked solar eruptions, climate (non-)effectsand old Mariner solar wind data (and the usual fear-mongering about the Sun). • The 2017 solar eclipse 'megamovie' ideas gets also advertised here, here and here. • There is now a Zeta Aur campaign (not for visual observers) and a Nova Sco 2011 #2 - while the developments with SN 2011fe in M101 - just past a peak at 9.9 mag. vis. - are covered here and here with numerous links.

In other news there was once more major confusion about Ramadan's end as observers struggled with the lunar crescent. • Another ridiculous contrail mistaken for a bolide, also discussed here, here and hier. • A huge flare from a satellite and hi-res images of NanoSail D from August and earlier. • The winners of Astronomy Photographer 2011 get covered e.g. here, here and here. • And finally the sky highlights for September - besides Garradd and the supernova - consist mainly of the opposition of Uranus on Sep. 25 when the planet reaches 5.7 mag. Dwarf planet (1) Ceres is in opposition today, but has only 7.7 mag.