Rare joint comet discovery by a spacecraft - and an amateur astronomer

The same says it all: C/2009 F6 (Yi-SWAN), pretty bright around 8th mag., was found simultaneously by a Korean amateur astronomer and the SWAN instrument on the SOHO spacecraft (which reported it first, but Yi's message came in before the first orbit was published, thus the double name). "On Apr. 4, R. D. Matson informed the Central Bureau that he had found a possible comet on ultraviolet SWAN images posted at the SOHO website," the story began on April 6 in IAUC #9034: " Numerous CCD astrometrists and one visual observer have reported confirmation of the object as a comet". And in #9035 we learn today that H. Yamaoka, Kyushu University, informs the Central Bureau that he received an e-mailed report on March 28 of the discovery by Dae-am Yi (Yeongwol-kun, Gangwon-do, Korea) of a possible comet with a noticeable greenish coma of diameter about 1' [...] on two 60-s CCD exposures taken about 80 seconds apart with a Canon 5D camera and a 90-mm f/2.8 camera lens. Orbital calculations suggest that this object is identical with C/2009 F6." Visual estimates put Yi-SWAN at 8.5 mag. right now, and the orbit suggests that this is about as bright as this comet will get; an ion tail has been detected. Another detection on March 25 was only made after the discovery announcement, thus it doesn't count.

In other small bodies news we have scientific papers about Spitzer observations of 67P (a current picture and more) and ground-based data on 17P/Holmes' outburst (also a current view), interesting developments of 19P, the recovery of P/2001 MD7, an old - but nice - picture of Kushida in the Hyades (a current picture and more) and Lulin on March 28 and March 24 (another picture) as well as its changes. Plus 4 comets on March 25. • In the Kuiper Belt, the moon of Orcus has been named Vanth; more interesting than the name is the fact that over 1000 suggestions had come in after the discoverer asked for suggestions. • There was another big bolide in Northern Ireland (more, more and more coverage) and one in Virginia which caused a lot of confusion at first (more, more, more, more, more [earlier], more, more [earlier], more and more). • The recovery of the (only one!) meteorite from the baltic bolide is recounted by the discoverer himself who also explained at a German meteor meeting how he found the shattered specimen in the grass and what it was like. At the same meeting a microbarometric signal from the exploding bolide was also shown, recorded with a machine like this - which is enormously sensitive! Yet another "dimension" of amateur astronomy has thus opened up.

In other news The solar activity remains low, making the current minimum rather deep, with no end in sight. • By the way, some STEREO images from the time of the last total solar eclipse. • Here is the slender crescent of Venus on April 5, April 2, March 28 and March 26 - and the inferior conjunction was also used by radio hams to get echoes from the surface with a big dish in Bochum (as a demonstration experiment for a possible future use of the latter in controlling an amateur mars spacecraft, no kidding). • Here are Saturn & six moons and the small storm on March 21. • And here is Jupiter with Io's shadow.

• A Pleiades occultation by the Moon was observed well in India as these, these, these and these pictures show. • Plus the very slender crescent on March 27. • There may be atmospheric effects from the eruption of Mt. Redoubt which has been quite productive and impressive to watch. • Here is the ISS in front of the Moon and well resolved; more nice pictures here, here and here - but a space-walking astronaut was not caught. • A funny software determining "your star" at any given time. • And a paper, summary and story about an ingenious student experiment to get the distance to the Moon from old Apollo recordings! • It's now DST also in Europe - and the controversy continues. • Finally some April highlights in the sky (more, more, more, more and more stories):

• April 8: Birkat Ha-Hammah or "Blessing of the Sun", a rare 'phenomenon' in some branches of Judaism where the alleged return of the Sun to its celestial position at creation time is marked only every 28 years.
  
  
• About April 9 til May 2: Best evening apparition of Mercury, now almost fully illuminated, with the half phase and greatest elongation on April 22 and 26, resp.
  
  
• April 15: Very close conjunction of Mars and Uranus, low over the Eastern horizon.
  
  
• April 21/22: In the morning peak of the Lyrid meteors.
  
  
• April 22: The Moon occults Venus for most of North America.
  
  
• April 24: "The position of the Sun and the shape of the Earth" - a worldwide didactical experiment employing elementary techniques. Join the party!
  
  
• April 26: Line-up of the lunar crescent, the Pleiades and Mercury in the evening.