Image source: Stellarium

From Cygnys to Polaris

Hoping there are clear skies and field of view, shall we visit the southern quadrant of the nighttime sky today, within the Cygnus Arm of our home galaxy?

            Beginning at the zenith and working our way down to the horizon, the glorious Northern Cross asterism that stands out among the less bright stars of Cygnus the Swan help to locate many other constellations. Surrounded by the stars of the Milky Way, the star at the top of the cross is Deneb, which is on the tail of the swan. Deneb is a blue-white supergiant star.  It’s about 196,000 times more luminous than our Sun. Deneb contains about 20 solar masses; its distance is uncertain. Deneb has a diameter about 203 times that of the sun which makes Deneb one of the largest type A spectral class stars known. For more information on Deneb, visit: https://earthsky.org/brightest-stars/deneb-among-the-farthest-stars-to-be-seen/

            The base of the cross, or the sword as others have named it, is an intriguing mix of several stars, collectively called Alberio. (Video: https://www.youtube.com/watch?v=Jyt84xqm8W4). If you watch the video, new information is shared about the stars that actually appear to be only one as the European telescope GAIA reveals long-held secrets about the star(s). (Here’s another video: https://www.youtube.com/watch?v=LrV7xeAM7bg).

            To the west of Cygnus is the dainty smaller trapezoid of Lyra, the harp with its bright star Vega dancing at the western corner at the top of the constellation. To the west of Lyra is the keystone of Hercules. Those stars are faint and light pollution will make the possibility of seeing it slight.

            Below the base of the cross is the constellation Aquila, which is an eagle but happens to have a vague sting-ray or stealth jet shape. The brightest star in the group is Altair, at the edge of the Milky Way Cygnus Arm, near the equator in the sky-if one imagines it extended into the sky that is.. Just west of the eagle is the Physician, Ophiuchus. This group of stars resembles a drawing of a house as done by a kindergartener with its brightest star the peak of the roof. There is an interesting story connected with Ophiuchus that you might enjoy reading as written by Ian Redpath, a name well-known to most star-gazers. (http://www.ianridpath.com/startales/ophiuchus.html)

            Very close to the horizon on the edge of the Milky Way haze is the Teapot asterism of Sagittarius, the Archer. A small faint haze clusters above the spout of the teapot as steam emerges from the hot pot (https://earthsky.org/favorite-star-patterns/teapot-of-sagittarius-points-to-galactic-center/). Perhaps it is concern over the contents of that teapot that causes the Scorpion’s major star, Antares, to be so red. Anti-Aries is a fun star to see. Translated to mean “Rival of Mars,” the Red Planet is often in the constellation so ancient sky watchers named it that.

            If we face the opposite direction the ever present circumpolar constellations are continuing their carousel dance throughout all seasons, merely moving from east to west about the North Star, Polaris. As our degree of latitude here in the RGV is 25.9017° N, 97.4975° W, this means Polaris is almost 26 degrees above local horizon. So, if one imagines those degrees on their geometry class protractor and stretches out their right arm and sights along it, that would put them in the neighborhood at least to locate the very faint important star. Sorry-it is not bright and not overhead at our geographical location folks.

            With this in mind, Polaris is the last star in the handle of the Little Dipper asterism, or the top of the Little Bear’s tail. The Big Dipper is below the horizon except for its handle and the faint constellation Draco the dragon is wound between the two and slightly below that star in Lyra, Vega, with Deneb from Cygnus near the zenith. 

            Another crooked little house to the east and above Polaris is King Cepheus, or King Ashurbanipal, an Assyrian monarch during the 7th century BC-and he is even mentioned in the Old Testament (https://www.biblegateway.com/resources/encyclopedia-of-the-bible/Ashurbanipal). History and astronomy are two favorite topics of mine so I am sharing this site in case you also might want to know more about this king of Ninevah’s ancient days. To the east of the king is his queen, Cassiopeia, a splendid W or M of stars.

            Until next time, KLU and if you have comments or questions, send them to me, carolutsinger@att.net