Planetary Alignments

Jupiter, Venus, Saturn and the Moon put on a good show this week in the evening sky. To see this you will need a very good western / southwestern horizon and clear skies. As Jupiter and Saturn recede into the sunset sky a bit lower each evening, Venus is racing out of the glow of the sunset sky and emerging as our evening 'star' for December and the coming months.

Of course, the planets and the Moon all occupy roughly the same path across the sky, so when planets align the Moon is often not far away. On Wednesday and Thursday and Friday the Moon will closely pass below and then above the Jupiter-Venus conjunction and then a day later, Saturn. The young Moon is always a treat to view in binoculars or a telescope, and having Venus and Jupiter and Saturn nearby will make the apparitions all the more exciting. The challenge here is that you will need to look very shortly after sunset, because within an hour most of these objects will set. Daily sky maps are here.

Clear skies!

Image courtesy of Sky & Telescope.

Follow Up Note: on November 28th I was on a plane flight above Germany and took this photo looking south west during the flight. The Moon is nicely placed between Venus and Jupiter. Venus is quite easy to find but Jupiter takes more work. Note that the Sky & Telescope diagrams (above) are based on the view from the US, so the Moon is past Venus, whereas I saw the alignment many hours earlier when the Moon was still between the two planets.

Meteors, Meteors, Meteors!

November brings the annual Leonid meteor shower which peaks on Sunday November 17th. This year we have a second potential show, a "Meteor Outburst" on the evening of November 21-22. Unforunately the Moon will interfere quite a bit with the Leonids, but will have considerably less impact a few days later for the meteor outburst. Let's look at these two events in more detail.

Leonid Meteor Outburst in 1833

Meteor showers are some of the most exciting spectacles to watch in all of astronomy. However, the best views require dark, clear eastern skies and a willingness to be awake when most people are sleeping. And this time of year, they require warm clothes! If skies are clear, the Leonid Meteor Shower should be visible this weekend during the night of of November 17-18, but because of the 3/4 lit Moon, the sky will be glowing and only the brightest meteors will be visible.

Meteors are tiny bits of rock and dust that enter the earth's atmosphere and burn up. These bits of rock and dust are floating in long orbits in space and the earth "runs into" these clouds of rock and dust. Because the earth is moving so fast, the rocks and dust that are struck by the earth heat up from the friction of earth's atmosphere. The result of this are brilliant streams of light that are often called "shooting stars" but aren't stars at all, just very small visitors that shine briefly and flicker out.

The meteor shower coming up this weekend is called the Leonids and it is the result of the meteor stream from a comet known as Temple-Tuttle (comets are usually named after their discoverers). The shower is called Leonids because the comets appear to originate in the part of the sky where we find the constellation Leo the Lion. This constellation does not rise in the east until very late in the night and as such, we don't get the best view of the Leonids meteors until after midnight. This article by Deborah Byrd on EarthSky is very informative about the Leonids this year.

The "Meteor Outburst" a few days later is due to a similar cause as the Leonids themselves, the debris stream from a yet-to-be-discovered comet that has left a trail through which Earth will pass. That will happen on the night of November 21-22. This article from Sky & Telescope Magazine does an excellent job outlining the circumstances of the outburst and indicates that in the US you can expect a peak on the 21st around 8:50 pm pacific, 11:50 pm eastern, and here in Munich Germany around 5:50 am on the morning 22nd. I'll be up early to see if in fact we will get 100s of meteors storming in all at once. Can't wait!

Image credit: Public Domain / Wikimedia Commons

Transit of Mercury on November 11, 2019 - don't miss it !

On Monday November 11 we will have a chance to witness a very unique and special event, a transit of the planet Mercury across the face of our Sun. This is a rare event, happening only 13 times in a century. The next one won't take place until 2032.

What is a transit? It is a precise alignment of the Sun, Earth and another celestial body. In this case, that body is Mercury, the closest planet to the Sun and a fairly small planet. It orbits the Sun every 88 days, and when we have this special alignment with a transit, we are witnessing the proper motion of the planet as it progresses in its orbit around the Sun. Mercury's diameter is 194 times smaller than the Sun so it will in fact appear as a tiny, perfectly round black dot against the surface of the Sun (the Photosphere) and will take approximately 5 1/2 hours to cross from solar limb to solar limb.

Time Lapse of Mercury Transit in 2016

If you want to see this, you will need special equipment that incorporates the correct level of filtering to reduce the Sun's intensity to a safe level, and magnification to make it possible to see the shape of Mercury against the disk of the Sun. Many astronomy clubs and public observatories will host viewing events. Here in Munich, the Volkssternwarte München will be open for the entire duration that the transit is visible from here, starting at 1:35 pm and continuing through sunset which is at 4:39 pm on Monday. We just need clear skies and a proper filter and we can enjoy this unique and rare event.

For general information about the transit and more detailed timing for US-based locations, check out this article from Space.com.

Warning: do not stare directly at the Sun for any length of time, and in particular do not look at the Sun through a telescope or binoculars with "eclipse glasses" as these will not protect your eyes sufficiently. Only observe the Sun directly with a high quality solar filter built especially for a telescope or binoculars.

Image courtesy of NASA.