StarWatch: Moravian College Astronomy

FEBRUARY 2021

FEBRUARY STAR MAP | MOON PHASE CALENDAR | STARWATCH INDEX | NIGHT SKY NOTEBOOK

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lunar phases

1277 FEBRUARY 7, 2021: The Winter Group: February is the best time for seeing the Winter Group, the assemblage of constellations in the south most associated with the winter season. Before proceeding any further, take a moment to look at the map below. Included within the Winter Group is the Heavenly ‘G” and the Winter Triangle. It’s always best to start with Orion the Hunter; its three closely spaced stars of its belt often capture the eye’s attention first. Above are the two shoulder stars, Betelgeuse (left) and Bellatrix. Betelgeuse, a red supergiant and variable star, dipped in brightness last year from obscuring dust in its atmosphere. It has now recovered. Below Orion’s belt is the blue supergiant Rigel, currently the brightest luminary of the Hunter with the bluish star Saiph to the left. The belt stars of Orion, Mintaka (right), Alnilam, and Alnitak are the starting point to finding two other winter patterns. Use these three stars as a rocket launcher and journey upwards to the bright giant star Aldebaran, the orangey eye of the V-shaped head of Taurus the Bull. Continue on a little farther and you’ll pass the Pleiades or Seven Sisters, the best open cluster in the entire sky, a region where stars were born about 100 million years ago. It has a fuzzy appearance, but binoculars will really make them pop. Use the three belt stars as a sliding board and down you will travel to the brightest star of the nighttime sky, Sirius, the Dog Star of Canis Major, the bigger of the two hunting canines of Orion. Above Sirius and slightly to its left is Procyon, the alpha star of Canis Minor, the lesser dog of Orion. Connect Procyon, Sirius, and Betelgeuse to form the Winter Triangle. Composed of brighter stars than the Great Summer Triangle, it still does not have the same appeal as its summer relative, probably because it is embedded in the richest concentration of bright stars in the heavens, and it can only be seen in the winter—burr. Using Orion, the Twins of Gemini, can also be found. Connect a line between Rigel and Betelgeuse and move upward about one and one half of its lengths. You’ll be hovering over two bright stars, the heads of the Gemini Twins, Castor and Pollux. Their separation is just a little greater than Orion’s three belt stars, and they are the brightest luminaries of the constellation. From my suburban neighborhood, Gemini looks like a rectangular box that I have called the Gemini coffin. Near the zenith, above Orion, lies the pattern of Auriga the Charioteer with its alpha star, Capella, the sixth brightest luminary of the nighttime sky. You are now ready to make the heavenly “G.” The brightness ranking of each star with respect to other stars of the night will appear after its name. Start with Capella (6) and continue counterclockwise past Castor (23) and Pollux 17), Procyon (8), and Sirius (1). Continuing the sweep, connect Rigel (7), Aldebaran (14), Bellatrix (26), and finally Betelgeuse (10), and you’ve done it. The challenge of discovering the Heavenly “G” is not finding the stars themselves, but understanding that the “G” is greater than the total sweep of your vision. You’ll have to move your head to fathom the vastness of the entire asterism, a group of stars with the fame of a constellation, but not accepted by professional astronomers as an official star pattern. Have fun getting to know the Winter Group, the Winter Triangle, and the Heavenly “G.” Ad Astra!

1278

FEBRUARY 14, 2021: Berenice’s Love

With the Big Dipper now on the rise after sundown, the sky is slowly giving way to the early spring constellations, but you will still have to wait until 10:30 p.m. to see the hair of Berenice and view for yourself the tangible commemoration of the great sacrifice made by her to ensure the safe return of her husband, the Egyptian king, Ptolemy III Euergetes (reigned 246 to 222 BC). See the map below. The Hair of Berenice, Coma Berenices, was originally the tuff of hair at the tip of Leo the Lion’s sinuous tail, but in star lore, it was transformed into the hair of Berenice by the royal astronomer Conon who was in the court of Ptolemy. Coma Berenices is described by American science writer, Garrett P. Serviss, in his 1888 book, Astronomy with an Opera Glass, as “a curious twinkling, as if gossamers spangled with dewdrops were entangled there.” Today, Berenice’s hair is visible in that manner only from a rural setting. I have seen it that way from dark Southwestern skies. Binoculars or an opera glass is needed from suburbia to obtain that same adjectival description. Serviss continues, “The constellation has a very romantic history. It is related that the young Queen Berenice, when her husband was called away to the wars, vowed to sacrifice her beautiful tresses to Venus if he returned victorious over his enemies. He did return home in triumph, and Berenice, true to her vow, cut off her hair and bore it to the Temple of Venus. But the same night it disappeared. The king was furious, and the queen wept bitterly over the loss. There is no telling what might have happened to the guardians of the temple had not a celebrated astronomer named Conon led the young king and queen aside in the evening and showed them the missing locks shining transfigured in the sky. He assured them that Venus had placed Berenice’s lustrous ringlets among the stars, and as they were not skilled in celestial lore, they were quite ready to believe that the silvery swarm they saw near Arcturus had never been there before. And so for centuries the world has recognized the constellation of Berenice’s Hair.” In a slightly different rendition of the story, Percy M. Proctor, in Star Myths and Stories, 1972, writes that it was Conon who advised Berenice to sacrifice her hair which was her pride and joy to Venus. Likewise, it was Conon who received the ire of the royal couple the following morning when the hair was discovered stolen from the Temple of Venus. Conon implored Ptolemy and Bernice to wait until evening to witness something very wonderful that had transpired in the sky. When evening arrived, Conon revealed the former tuff of the Lion’s tail as the new constellation of Coma Berenices. Proctor writes, “…as long as the stars continued to shine, they would be a reminder of the great love which had made her willing to sacrifice her greatest treasure to ensure the safe return of the man she loved.” Conon’s life was spared with gratitude. Happy Valentine’s Day!

Map created by Gary A. Becker using Software Bisque's The Sky...

1279 FEBRUARY 21, 2021: Ironic, This Concept of Diversity: One of the great joys of astronomy for me is to look at photos of the vast array of objects that can be seen when we turn our eyes or telescopes to space. Rich colors abound as do interesting shapes and patterns, whether it be the Andromeda Galaxy, the Crab or Horsehead nebulae, a starscape visible on a cool summer’s evening, or any of the eight planets and their 158 confirmed moons, all with varied topographies and hues. I find it fascinating that there are so many different but compelling vistas to see. • Back on Earth, there are an estimated 8.7 million species that share our home. Over 90 percent of Australia’s reptiles, amphibians, flowering plants, and conifers are endemic to that continent. Diversity seems to be not only in our own perspectives of the universe, but as a genuine part of the DNA of the universe. • Humans are incredibly individual. We have our own way of being unique—so much so that we become excited when we see twins who are alike. I wonder how the universe would be without all of its variety? What would it look like? In astronomy if every planet, moon, star, or galaxy were essentially the same, would we even consider approaching the study of the universe in the same manner that we do, or would we simply say, “Been there, done that?” • Part of the concept of inquiry is to examine differences. From a scientific perspective, human beings have been singularly blessed as a species to be the most curious, to approach problems with a multitude of questions, and to seek answers for them without bias. There seems to be no end to these queries about the universe in which we reside. I would even say that we need diversity to survive. • If we examine our isolation and repetition during this pandemic, we get a taste of a world where social interaction is curtailed or even nonexistent. There is a monotony to our being. The vibrance of new experiences is lost to a people who love to be gregarious, but cannot be for fear of the contagion; hence that is why we chafe over the restrictions that are imposed upon us. • Diversity is necessary. We know that to give up our social contacts now, we can once again return to normalcy in our future lives. • COVID is showing us how important it is to be individualistic, by showing us the opposite—the utter boring snapshot of our world today where everyone is alike, similar to the world of Camazotz in Madeleine L'Engle’s, A Wrinkle in Time, where we see a stagnant society that is controlled by a huge brain that suppresses individuality. • If diversity is in the DNA of the universe and our own planet, then why is there such a push for some humans to reject the rights of others to be different and shun what the universe is attempting to teach us? The universe is giving us a clear example to be unique. Why not heed its call?

1280 FEBRUARY 28, 2021: Edge of Spring: One of my all-time favorite rock hits is Stevie Nicks’, Edge of Seventeen. With its distinctive guitar “chugging,” I always feel a desire to break free “just like the white winged dove” when I hear its melody. I am also aware that the lyrics have a totally different connotation. Likewise, as we depart February, we are getting ever closer to spring with its increasing daylight and the positivity that this season always brings. The first moment of spring occurs on March 20 at 5:40 a.m. However before that, we first will spring ahead one hour on Sunday, March 14, when 2:00 a.m. Eastern Standard Time (EST) instantaneously becomes 3:00 a.m. Eastern Daylight Time (EDT). Keep in mind that we don’t really gain an extra hour of sunlight; we just redistribute the light of day so that the sunshine hours fall more in step with our waking hours. Regardless, the feeling that daylight is suddenly exploding all around us with the returning warmth of the sun has always been invigorating to me. All of this is the result of the Earth’s 23.5-degree axial tilt to the perpendicular of its orbital plane (the ecliptic). To put this another way, the daily motion of stars and planets across the sky, a reflection of Earth’s rotation (spin), is at an angle of 23.5 degrees to the sun’s daily movement, due to Earth’s revolution (orbit) around our daystar. As a result, the sun’s annual displacement above and below Earth’s equator must be the same amount, ±23.5 degrees, for a total of 47 degrees. The noontime winter and summer solstice suns are displaced by a total of 47 degrees. • At the time of the winter and summer solstices (sun still), there is very little change in Sol’s up and down motions. Winters and summers seem to move at the pace of a snail. Presently, we are approaching that time of the year when the changing vertical movement of the sun is at its greatest. Unlike our switch to Daylight Saving Time which adjusts sun time to wake time, this causes a real modification in the amount of daylight that we will be receiving, and in the spring that change is all positive. • For example, let’s take a look at the Lehigh Valley which is 40.5 degrees north of the equator. During the one-month interval between March 1 and the 31st, the sun’s altitude, its height above the horizon at local noon, will increase from 39 degrees to 51 degrees. That’s a 12-degree displacement in one month. The amount of daylight that we will be receiving will likewise increase by 1 hour, 22 minutes. The sun is above the horizon for 11 hours, 18 minutes on March 1. This grows to 12 hours, 40 minutes on March 31. That is a big change, but it would be even greater if the 31-day interval of time were centered on the vernal equinox, when the positive increase in the noontime altitude of Sol is at its greatest. Take the four-month interval between November 1 to February 28. The sun begins at a noontime altitude of 34.5 degrees, dips to 26.5 degrees by the winter solstice, and recovers to only 39 degrees by the end of February, a net gain of 5.5 degrees. The amount of daylight remains consistent, averaging about 9 hours, 50 minutes during the entire four-month period of time. • As we move into March, it is time to celebrate because we are definitely on the “edge of spring.” Ad Astra!