The planetary trio has become a quartet this morning, as Venus, Mars and Jupiter were joined by the waning crescent moon. Although it was a little painful to get up at 5:30 a.m., I didn't regret having done so, and was rewarded by this beautiful view above Santiago de Chile.
This is 'Halloween Asteroid' 2015 TB145, as it was approaching Earth, imaged with the Arecibo telescope radar. As it turned out, the space rock measures around 600 meters and rotates once every five hours around its axis. It is thus larger than initially thought.
A 'halloween asteroid' is approaching. First off, regardless what you might hear on 'the internet', there is no danger of a collision with 2015 TB145. The 400-something-meter space rock will pass Earth on October 31, 17:12 UT, at a safe distance of 494,000 kilometers, which is 1,3 times the distance to the moon. Close enough however to be seen with small backyard telescopes - if you know where to look.
Chile is rapidly evolving to become the world's center of observational astronomy. With some of the best international observatories already taking advantage of its exceptional clear (and dark) skies, and with future giant telescopes to be operational within the next decade, the South American country will muster 70% of the world's ground based observational infrastructure in the 2020s.
Alpha Centauri is the nearest star to the unaided eye, and the third brightest of the sky. A small telescope reveals it to be a beautiful double system: two stars similar to our Sun revolve each other in the span of a human lifetime. Because of their relative proximity, angular separation and position angle of the two components change notably in the matter of years, making this system particularly interesting to observe. This year, in November, the angular separation reaches a minimum of only four arcseconds.
On May 23, amateur astronomers across central Europe are in for a treat: Two asteroidal occultations within one hour, without having to change your seat. This is a pretty rare occurrence, as such events are only visible in a rather narrow paths on the ground.