In the Sky This Week – August 7, 2018

Fall stars have appeared in the eastern predawn skies; the constellation Orion is low in the east, a thin waning crescent Moon near it for the next few days. Over the coming weeks, Orion will appear a bit higher each morning as it moves slowly towards the southeast.

The waning crescent Moon and the constellation Orion are in the early morning sky to the east on August 7, 2018. The Moon also be visible in the early morning sky all week. Credit: Stellarium / Bob Trembley.

Mars and Saturn continue to be a great observing targets in the southern skies for weeks to come!

Mars and Saturn in the early morning sky to the south on Aug. 7, 2018. Credit: Stellarium / Bob Trembley.

Jupiter crawls slowly westward as the Earth continues to pull away from the giant planet; Jupiter will continue to dim over the next several weeks, and will set earlier each evening.

Jupiter and Saturn in the southern sky at 10:00 PM, Aug. 7 2018. Credit: Stellarium / Bob Trembley.

Venus is catching up with the Earth, and appears lower each evening in the western sky at dusk. The current half-phase of Venus is quite obvious in telescopes.

Venus and Jupiter are in the southwestern sky at dusk, Aug. 7, 2018. Credit: Stellarium / Bob Trembley.

Southern Hemisphere:

From Buenos Aires, Argentina, the waning crescent Moon and Orion appear in the east-northeastern sky predawn sky. The Moon and Orion appear flipped from how I see them in Michigan – the Moon appearing as it does to me in a waxing crescent phase at dusk in the west.

The Moon and Orion in the eastern predawn sky as seen from Buenos Aires, Aug 7 2018/ Credit: Stellarium / Bob Trembley.

On overhead view from Buenos Aires after dusk is simply a spectacular splash of planets across a sky bisected by the disk of the galaxy. Seeing the sky from the southern hemisphere is high on my “bucket list.”

The southwestern and overhead sky after dusk as seen from Buenos Aires, Aug 7 2018/ Credit: Stellarium / Bob Trembley.

The Moon

The Moon is a waning crescent visible in the eastern predawn sky. The Moon will be new on August 11^th, and will return as a waxing crescent, visible in the western sky at dusk later in the week.

The Moon from Aug. 7-14, 2018. Visualizations by Ernie Wright

Observing Target: Jupiter

Jupiter in an 8 inch Dobsonian telescope. Credit: Bob Trembley, Jan. 10, 2010

Jupiter won’t be around much longer, so catch a glimpse of it now while you can! I’ve shown Jupiter to many people in recent weeks – it’s always a treat!

At a recent meeting of the Warren Astronomical Society, a member mentioned seeing a dark storm in the northern latitudes.

The Hubble Space Telescope has imaged Jupiter and its moons many times over the couple decades

Constituent Image for Jupiter/Ganymede Compass and Scale Image. Credit: NASA, ESA, and E. Karkoschka (University of Arizona)

This dazzling Hubble Space Telescope photo of Jupiter was taken when it was comparatively close to Earth, at a distance of 415 million miles. Hubble reveals the intricate, detailed beauty of Jupiter’s clouds as arranged into bands of different latitudes, known as tropical regions. These bands are produced by air flowing in different directions at various latitudes. Lighter colored areas, called zones, are high-pressure where the atmosphere rises. Darker low-pressure regions where air falls are called belts. The planet’s trademark, the Great Red Spot, is a long-lived storm roughly the diameter of Earth. Much smaller storms appear as white or brown-colored ovals. Such storms can last as little as a few hours or stretch on for centuries. Credits: NASA, ESA, and A. Simon (NASA Goddard)

NASA’s Juno mission is in orbit of Jupiter; citizen scientists have been processing raw data returned from Juno and producing some truly spectacular images:

The Perseid Meteor Shower

“The Best Meteor Shower of the Year“™ happens this week. The Perseid meteor shower happens on August 12^th. Observatories, museums and venues around the planet will be hosting star parties. Here’s hoping you catch a nice fireball!

The Perseid meteor showers appear to radiate from the constellation Perseus. Perseus is visible in the northern sky soon after sunset this time of year. Credit: NASA/JPL-Caltech

The Sun

The Sun as been spot-free for 4 days – two active regions with coronal loop activity are facing Earth. The huge coronal hole at the north pole from last week remains, and a couple small equatorial holes are near the center of the Sun’s disk

The solar wind speed is 362.4 km/sec, with a density of 26.2 protons/cm³  that’s the thickest I’ve seen the wind!

SpaceWeather.com says: “The sun has been without sunspots for 38 of the past 41 days. To find a similar stretch of blank suns, you have to go back to 2009 when the sun was experiencing the deepest solar minimum in a century. Solar minimum has returned, bringing extra cosmic rays, long-lasting holes in the sun’s atmosphere, and strangely pink auroras.”

There appear to be small prominences all over the Sun the last couple days; one active region will soon be rotating out of view as another, larger one rotates into view.

Asteroids

Upcoming Earth-asteroid encounters:

Notes: LD means “Lunar Distance.” 1 LD = 384,401 km, the distance between Earth and the Moon. Table from SpaceWeather.com

Near-Earth objects (NEOs) discovered this month: 1, this year: 973, all time: 18525.
Potentially hazardous asteroids: 1912 (as of July 31, 2018)
Minor Planets discovered: 779,736 (as of July 31, 2018)

Fireballs

On Aug. 6, 2018, the NASA All Sky Fireball Network reported 75 fireballs.

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point–Earth. Source: Spaceweather.com

The Solar System

This is the position of the planets and a couple spacecraft in the solar system:

Position of the planets in the inner solar system – a few days after Mars opposition – Aug 7, 2018. Credit: NASA Eyes on the Solar System / Bob Trembley.

Position of the planets in the middle solar system, Aug. 7, 2018. Credit: NASA Eyes on the Solar System / Bob Trembley.

Exoplanets

Confirmed Exoplanets: 3,774 (7/19/2018)
Multi-Planet Systems: 625 (7/19/2018 )
Kepler Candidate Exoplanets: 4,496 (8/31/2017)
TESS Candidate Exoplanets: 0
Data from the NASA Exoplanet Archive

Apps 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.

2018 is NASA’s 60th anniversary!