In the Sky this Week – September 12, 2017

Mercury is about as high as it’s going to get in the eastern predawn sky on the 12^th, and will start getting lower each morning. Sirius is high in the sky, and the constellation Canis Major is now fully visible above the southeastern horizon before sunrise. Mercury and Mars will appear very close to each other in the eastern predawn sky on the 16^th.

Credit: Stellarium / Bob Trembley.

Saturn continues to be a great observing target in the southern sky after sunset.

Southern sky at 9:00 PM Sept. 12, 2017. Credit: Stellarium / Bob Trembley.

The Moon will be in conjunction with the star Aldebaran on the morning of the 12^th, and will appear between(ish) the stars Aldebaran and Betelgeuse on the 13^th.

Conjunction of the Moon and the star Aldebaran on the 12th. Credit: Stellarium / Bob Trembley.

The third quarter moon near the stars Aldebaran and Betelgeuse on the 13th. Credit: Stellarium / Bob Trembley.

The eastern predawn sky on the 18^th should look pretty interesting: Mercury, Mars, a sliver of a waning crescent Moon, the star Regulus and Venus will all appear in a line.

Conjunction of the Moon, Mercury, Mars, Regulus and Venus – Sept. 18, 2017 6:00 AM. Credit: Stellarium / Bob Trembley.

Sunspot AR2680 has rotated into view; this sunspot is about the same size as AR2673 was from last week – which ballooned out and blew off two of the largest solar flares we’ve seen in quite a few years… so we’ll be keeping a wary eye on this sunspot.

The Sun – Sept. 12, 2017 – Helioseismic and Magnetic Imager (HMI). Image courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. / Bob Trembley.

AR2673 and AR2674 have rotated out of view, large coronal loops associated with AR2674 can still be seen on the limb of the Sun (right side of image below).

The Sun’s Corona – Sept. 12, 2017 – Atmospheric Imaging Assembly (AIA) 171 angstroms. Image courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.

This video shows a very active corona between Sept. 10-12, 2017:

The Sky Overhead – Sept. 12, 2017 9:00 PM. Credit: Stellarium / Bob Trembley.

The Sky Overhead – Sept. 12, 2017 6:00 AM. Credit: Stellarium / Bob Trembley.

The Solar System – Sept. 12, 2017. Credit: NASA Eyes on the Solar System / Bob Trembley.

Apps used for this post:

Stellarium: a free open source planetarium app for PC/MAC/Linux.
NASA Eyes on the Solar System: an immersive 3D solar system and space mission app – free for the PC /MAC.