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Teapot of Sagittarius: In the direction of galaxy’s center

Two things set Sagittarius apart from all other constellations: the winter solstice sun shines in front of it, and it marks the direction to the center of our Milky Way galaxy.

When to see it
Two things set Sagittarius apart from all other constellations. First, Sagittarius marks the direction to the galactic center. Second, the sun shines in front of Sagittarius on the December solstice – the Northern Hemisphere’s winter solstice. The December solstice – also called the southern solstice – falls annually on or near December 21.

Although modern stargazers have a hard time seeing Sagittarius as the Centaur sporting a bow and arrow, The Teapot – the famous star pattern lighting up the western half of Sagittarius – is fairly easy to make out. The Teapot is an asterism – a star formation that is not a recognized constellation.

Because the sun passes in front of Sagittarius from about December 18 to January 20, the Teapot is not visible or easily seen during winter. However, about a half year later – on July 1 – the Teapot climbs to its highest point for the night around midnight (1:00 a.m. daylight saving time), when it appears due south. As seen from our mid-northern latitudes, the Teapot rises in the southeast about 3 hours before its climbs to its highest point, then sets in the southwest about 3 hours afterwards.

The Teapot returns to the same place in the sky about 4 minutes earlier with each passing day, or 2 hours earlier with each passing month. On August 1, the Teapot climbs to its highest point around 10:00 p.m. (11:00 p.m. daylight saving time). On September 1, it climbs highest around 8:00 p.m. (9:00 p.m. daylight saving time). On October 1, it’s highest around 6 p.m. (7 p.m. daylight saving).

The Teapot is best viewed during the evening hours in late summer and autumn.

By August, Sagittarius and its Teapot pattern are fully up after sunset. In a dark sky, you can see that the starry band of the Milky Way in our sky is broader in this direction - the direction toward the center of our galaxy. Image via UCIrvine

Center of our Milky Way galaxy

On dark, moonless summer and autumn nights, look for the “steam” billowing out of the Teapot spout. This “steam” is really an edgewise view of the galactic disk, the combined glow of millions of stars running astride the galactic equator (see sky chart). Although all the stars that you see with the unaided eye belong to our home galaxy, the Milky Way, the term Milky Way often refers to the luminescent band of stars that arcs across the heavens. From a dark country sky, scan this river of stars with binoculars. This region of the sky is a virtual treasure chest, chock-full of star fields, star clusters, galactic nebulae and dust. Some of the more famous binocular deep-sky objects are highlighted on our sky chart.

Great alignment with galatic plane in 2012?

On our sky chart above, we highlight the ecliptic – the annual pathway of the sun in front of the backdrop stars. The sun and Earth align with the galactic equator (plane) yearly on or near the December winter solstice, so there is nothing out of the ordinary about the so-called “galactic alignment” of December 21, 2012.

Can you spot the direction to the galactic center on our sky chart, to the southwest (lower right) of the winter solstice point, and to the west (right) of the Teapot? This lets you know that the sun and Earth do not align with the galactic center in 2012, or in any year in the foreseeable future.

Bruce McClure