Saturn, Mars, Jupiter, Antares and Spica continue to be highlights in the southern predawn sky. The Earth is slowly catching up to Mars in its orbit, and Mars appears to be moving in an easterly direction, as Jupiter heads in a westerly direction – the distance between the two planets growing with each passing day.
Southern predawn sky, Feb. 20, 2018. Credit: Stellarium / Bob Trembley.Uranus and the Moon are in the western sky after sunset; there aren’t any particularly bright stars near the Moon for the next several days.
Western sky shortly after sunset, Feb. 20, 2018. Credit: Stellarium / Bob Trembley.The Moon
The Moon this week. Visualizations by Ernie WrightThe Moon is a waxing crescent in the western sky near dusk, and will be at first-quarter on the 23rd. The Moon will be a waxing gibbous after the 23rd heading towards full next week.
This entire week would be a great time to host a star party and have the public look at the Moon through telescopes.
The Sun
The flare-crackling sunspot from last week has rotated out of view, and the Sun has been spot-free for 3 days now. The coronal hole at the Sun’s north pole has completely closed up, and the one along the equator has vanished. There is a large coronal hole at the Sun’s south pole; SpaceWeather.com says: “There are no large and coherent coronal holes on the Earth-facing side of the Sun.” The solar wind speed is 434 km/sec, with a density of 4.0 protons/cm3.
[Click to see a still image of the Sun in this frequency from today]
There have been several prominences in the Sun’s chromosphere over the last several days:
[Click to see a still image of the Sun in this frequency from today]
You can create your own time-lapse movies of the Sun here: AIA/HMI Browse Data.
You can browse all the SDO images of the Sun from 2010 to the present here: Browse SDO archive.
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Asteroids
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The Solar System
This is the position of the planets in the solar system:
Position of the planets in the solar system, Feb. 20, 2018. Credit: NASA Eyes on the Solar System / Bob Trembley.
Position of the planets in the solar system (side view), Feb. 20, 2018. Credit: NASA Eyes on the Solar System / Bob Trembley.The OSIRIS-REx probes shown in the above solar system images is an asteroid sample return mission; it will approach asteroid 101955 Bennu starting in August of 2018. OSIRIS-REx will fly in formation with Bennu while it surveys the asteroid’s surface for over a year. OSIRIS-REx will collect a sample of Bennu’s surface material in 2020, and return it to Earth in 2023.
The OSIRIS-REx probe near asteroid 101955 Bennu on Dec. 31, 2018. Image credit: NASA Eyes on the Solar System / Bob TrembleyApps used for this post:
Stellarium: a free open source planetarium app for PC/MAC/Linux. It’s a great tool for planning observing sessions.
NASA Eyes on the Solar System: an immersive 3D solar system and space mission simulator – free for the PC /MAC. I maintain the unofficial NASA Eyes Facebook page.
