This is just a pre-pre-warning with many caveats ... but if the first orbit for newly discovered comet C/2011 L4 (PANSTARRS) holds, it could put on quite a show when the visitor reaches a perihelion of only 1/3 AU in April 2013. A first visibility analysis by this blogger sees the comet very close to the horizon in the Northern hemisphere just after perihelion - when it may reach 2nd or 1st magnitude or even better - while it's better visible in the weeks before and right up to perihelion in the Southern hemisphere. Once the orbit stabilizes, these calculations will be repated in greater detail, and then it's up to the comet's brightness to perform. If it does work out as the standard formula implies, you read it here first ... • In other comet news the state of Elenin (and one more anti-BS article), new comet C/2011 L3 (McNaught) and continuing observations of the outburst of 174P/Echeclus. • On June 15 a faint asteroid will visit a bright star in Leo, and 2009 BD is feeling radiation pressure. • Opinion about the 2011 Draconids is still wildly split: Will there be hardly any meteors or 600 per hour or 1000 per hour ...?
Regarding larger bodies in the solar system the next Transit of Venus is (less than) a year away now, spawning this website and outreach ideas. • A close-up of Saturn & Porrima and another view with some Chronian satellites, too. • More previews of the June 15 total lunar eclipse here, here, here and here - and remember my old advice for the optimum experience! • Pictures of the June 3 lunar crescent here, here, here and here. • From the Midnight Eclipse the best movie (almost hypnotic ...), another one, one from Proba-2 and more coverage and image collections here, here, here, here, also great pictures from Norway (more) and Iceland. • A big solar eruption on June 7 (more and more animations and coverage here, here and here) led to some expectations for the Earth (see also here, here, here, here and here for some hysteria) that didn't materialize (see also here, here and here): Better look here first (and the U.N. will save us anyway :-). • Also the Sun on May 31, some wave phenomena and spectroscopy - and more details about Nova Sco.
The supernova 2011dh in Messier 51 is at about 13.4 mag. in the visíble right now as collected pictures & photometry and esp. visual estimates show. We have a gallery, calls by the Weizmann Inst. and Palomar Obs. for yet more (early) pictures of this apparent type IIb SN and selected pictures of June 7 (more), June 6 and June 3 (explained; more, more and more). As it has turned out this blogger played a role in the obtaining of the first-ever spectrum of the SN (also 'discussed' here and in the tweets here, here and here). There is a potential identification of the SN progenitor (easily visible in a public HST image of M 51), and the SN was seen in X-rays, by Swift's UVOT and in radio. Finally some more general coverage of the SN 2011dh here, here, here, here, here, here, here, here and here. • Finally a cool video with NLCs and aurora shot June 4 in Minnesota - and extremely detailled pics of the ISS & OV-105, also hailed here.