What’s Up: September 2017

It’s September and a wonderful time to enjoy the night sky. In northern latitudes, the length of night is generally outpacing the upcoming winter chill. Spring and Fall are great times to become reacquainted with the cosmos.

Here’s a brief run-down of what to expect in the September skies (note: this information is tailored to those of us in the Northern Hemisphere).

What’s that planet?:
If it’s in the evening, it’s most likely Jupiter. If it’s in the morning, you might be seeing Venus, Mercury or Mars.

This month, Jupiter is its bold, bright self, but it’s tracking fairly close to the Sun and setting in the southwest. You’ll see it shortly after sundown, earlier and earlier the further north you are. In October, Jupiter will be outside of our view until its return in November. On September 21 and 22, Jupiter will appear very near to a thin crescent Moon. Saturn is also up during September nights, though you’ll want to consult a star chart or skymap app to find it due to it being hard to distinguish from stars. Speaking of Saturn, September 15 marks the grand finale of the Cassini spacecraft. After 20 years of astonishing service, Cassini will plunge into Saturn’s atmosphere and end one of the most successful space missions imagined.

On September mornings, keep an eye out for Venus, Mars, and Mercury. Venus is hard to miss, it’s the brightest object in the sky following the Sun and Moon. Keep an eye to the east about two hours before sunrise (closer to sunrise the later we get into the month) for our bright sister planet.

If you’re fortunate enough to live on the mid-northern latitudes, you might get to witness a fantastic conjunction of Mercury and Mars. (If you’re as far north as Alaska, you’ll need a clear view of the horizon.) On September 16, Mercury and Mars appearing extremely close to each other in the morning sky. Use this website to get a custom report for your viewing location.

If you need help finding out when a planet rises and sets for your location, this website is fairly indispensable.

Happy viewing!

A Tale Of One Crater

Dickens Crater

(Dickens crater as imaged from the Messenger spacecraft / Image Source: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)

Charles Dickens was the acclaimed English novelist who brought the world such classics as ‘Oliver Twist’, ‘A Christmas Carol’, ‘Great Expectations’, and ‘David Copperfield’, among others (another is alluded to in the title of this post, but you knew that). Widely considered the greatest Victorian period author, he has been honored in many ways throughout the past century-and-a-half.

Dickens might have come to expect many of the honors he received, and those dedicated posthumously, but one that I don’t suspect he ever looked forward to was having a crater on the planet Mercury named after him. Nearly all Mercurian craters are named after artists; writers, painters, composers, etc. Naturally, Dickens wouldn’t be excluded.

The name of the 78km-diameter crater, Dickens, was approved by the International Astronomical Union in 1976, which appears to be the first year they began the unique naming program. (For your general interest, recent “inductees” are a couple of my favorite writers, Khalil Gibran and Rudyard Kipling; having their surnames assigned to craters in 2009 and 2010, respectively.)

For a full list of the currently-291 named Mercurian craters, check out this list.

First Ever Image From Orbit Of Mercury

Following insertion into Mercury’s orbit on March 17, Messenger has finally sent home the first images ever recorded from within the orbit of our innermost planet.

You’ll want to click this image for the full-size version:

First image ever captured from within the orbit of Mercury

First image ever captured from within the orbit of Mercury / Source: Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Early this morning, at 5:20 am EDT, MESSENGER captured this historic image of Mercury. This image is the first ever obtained from a spacecraft in orbit about the Solar System’s innermost planet. Over the subsequent six hours, MESSENGER acquired an additional 363 images before downlinking some of the data to Earth. The MESSENGER team is currently looking over the newly returned data, which are still continuing to come down. Tomorrow, March 30, at 2 pm EDT, attend the NASA media telecon to view more images from MESSENGER’s first look at Mercury from orbit.

Currently, Messenger is the commissioning phase of the mission and is testing out its various equipment and instruments. In a few days, it will begin its year-long primary mission which will answer questions about the formation and composition of the smallest and innermost planet in our solar system.

NASA Messenger Makes History Today

Artist depiction of the MESSENGER spacecraft in orbit around Mercury.

Artist depiction of the MESSENGER spacecraft in orbit around Mercury. / Source: NASA / JHU/APL

Today, at about 4:45 AKDT (8:45 EST), NASA’s Messenger will become the first spacecraft to enter Mercury’s orbit. Messenger launched on August 3, 2004 and will undertake a plethora of scientific tasks, including studying the chemical composition, geology and magnetic field of Mercury. It should increase our understanding of Mercury’s geological history, investigate the presence of a liquid outer core, and determine why Mercury’s Northern and Southern poles are highly-reflective to radar (the hypothesis is ice!).

NASA will broadcast a live webcast of the event: http://mfile.akamai.com/7111/live/reflector:22179.asx?bkup=22194 (streaming media link) beginning at 8:457:55pm EST.

The first few days in orbit, the orbital commissioning phase, will focus on ensuring that the spacecraft systems are all working well in the harsh thermal environment of orbit. By March 24, Messenger’s instruments will be activated and checked out, with the science portion of the mission commencing on April 4.

For more information about the mission:

NASA Messenger Mission Page
Ice on Mercury
Messenger Page -Johns Hopkins University – Applied Physics Laboratory