What's in the sky tonight?
September 25, 2013
-The Moon rises late this evening (around 11 p.m. depending on your location), with Aldebaran well to its upper right and brighter Capella farther to its upper left. Earlier, spot these two stars when they're low to judge where the Moon will rise.
-Near the center of the solar disk, growing sunspot AR1850 directly faces Earth. However, like all the other spots on the sun today, AR1850 is quiet and not flaring. The chance of a geoeffective flare today is low.
-Amateur astronomers around the world are photographing Comet ISON as it approaches Mars in the predawn sky. The comet is not as bright as some forecasters expected. What does that mean for ISON's future prospects? The answer may be found below this color photo of the comet obtained by UK astronomer Damian Peach on Sept. 24th. At the moment, Comet ISON is about as bright as a 14th magnitude star, which puts it one or two magnitudes dimmer than forecasts. Nevertheless, according to several experts speaking in a NASA video, Comet ISON is still on track to become an impressive sungrazer. John Bortle predicts ISON will rival Venus during the hours leading up to its closest approach to the Sun in November, while Matthew Knight notes that Comet ISON is brighter than Comet Lovejoy was at the same distance from the sun in 2011. Comet Lovejoy went on to become a spectacular naked-eye object. Comet ISON might do the same. The second comet below is a picture of Comet Lovejoy at its peak, which was only visible to the Southern Hemisphere.
Astro Picture of the Day:
September 25, 2013
Source:
Here in the Milky Way galaxy we have astronomical front row seats as M81 and M82 face-off, a mere 12 million light-years away. Locked in a gravitational struggle for the past billion years or so, the two bright galaxies are captured in this deep telescopic snapshot, constructed from 25 hours of image data. Their most recent close encounter likely resulted in the enhanced spiral arms of M81 (left) and violent star forming regions in M82 so energetic the galaxy glows in X-rays. After repeated passes, in a few billion years only one galaxy will remain. From our perspective, this cosmic moment is seen through a foreground veil of the Milky Way's stars and clouds of dust. Faintly reflecting the foreground starlight, the pervasive dust clouds are relatively unexplored galactic cirrus, or integrated flux nebulae, only a few hundred light-years above the plane of the Milky Way.