27 October 2013

The Royal Sky

Every Fall, the royalty of the sky rises in the north-east and showcases a very fine part of the sky that includes the outer reaches of the band of the Milky Way, a galactic treasure, and a few easy-to-spot patterns that are easily visible in the night sky.

The Royal Sky
The trio includes Cepheus (the King), Cassiopeia (the Queen), and Andromeda (the Princess). In the early evenings this time of year, they are in a line from nearly due North toward due East, and the middle of these three constellations is quite bright and easy to locate in the sky. Over the course of the evening, they gradually shift position, spiraling out from the north circumpolar region of the sky toward the zenith, following closely the Great Square of Pegasus (of which Andromeda shares a corner star, Alpheratz).

I enjoy looking at this region through binoculars, with the outer reaches of the Milky Way visible in and around Cassiopeia, and of course the treasure of this part of the sky, the Andromeda Galaxy (M31).  Take some time to enjoy this royal corner of the night sky, brimming with discoveries small and large. 

Image courtesy of Sky Safari.

11 October 2013

Comet C/2012 S1 - Comet ISON Approaches

Comet C/2012 S1
Comets are beautiful and engaging to watch, gracefully floating across the night sky, arriving unexpected and sometimes surprising us with an extraordinary show. Some comets are regular visitors to Earth ("short period comets" such as Halley's Comet) and are very predictable, but others arrive from the vast reaches of the outer Solar System (the Oort Cloud) and make only one pass through our neighborhood, never to be seen again. Comet C/2012 S1, better known as Comet ISON, is of the latter category, packing enough ice and mass to become 'the comet of the century' when it has a rendezvous with the Sun in late November. Predictions of spectacular comets sometimes miss (anyone remember Comet Kohoutek?) so we always try to plan for comets with lowered expectations and hope to be pleasantly surprised.

Finding Comet ISON
Comet ISON passed near Mars a few weeks ago and is on a near-collision course with the Sun. A comet with a close encounter like this is called a Sungrazing Comet -- Comet ISON will pass within a solar diameter of the Sun, so close that it might not survive the trip back out of the Solar System. If it does, however, it is expected to have a beautiful tail and could be quite a spectacle. We have to watch and see.

This coming week provides an opportunity to spot Comet ISON as it appears in the morning sky, when it will be in close alignment with Mars and the bright star Regulus. Look to the east before sunrise (around 5:00 or 6:00 am) and use some kind of optical aid such as binoculars, and you'll have a nice view of the comet. I'll be out each morning to take a look, and will update the blog with news.

Images courtesy of NASA/Hubble, and EarthSky.org.

Update October 15: have tried two mornings in a row to spot ISON with binoculars from San Francisco, but have not yet found it. Either it is quite tiny, too faint, the skies here are too light polluted, or all of the above. Will continue to try the remainder of this week.