StarWatch: Moravian College Astronomy

StarWatch for the greater Lehigh Valley

MARCH 2018

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

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1124 MARCH 4, 2018: Ready to Spring Forward?: I am so excited that finally daylight saving time (no “s”) is almost upon us. You’ll be “springing” ahead one hour on Sunday morning, March 11. If you do not set your clocks forward by one hour, then you must be living in Arizona (except for the Navajo Nation) or Hawaii. There is no 2-3 a.m. on Sunday, March 11, if you are working third shift. Will you be paid for eight hours of labor or the seven hours that you will actually be employed? Lots of people really think that they are gaining an extra hour of daylight, but it really is just an illusion. Our Eastern Standard Time technically shifts to Atlantic Standard Time which is one hour ahead and the next time zone to the east. This causes the sun to rise one hour later, but also to set an hour later giving us the impression that we have gained that extra hour of light. The amount of daylight, however, is actually expanding. The sun is rapidly moving northward, climbing higher into the sky each day, rising earlier and setting later, increasing the actual amount of time the sun is visible. The interval between the initiation of daylight saving time and the first week in April, a span of four weeks, sees the sun climb higher into the sky than at any other time of the year, increasing its noontime altitude by 10 degrees and the amount of daylight swelling by one hour, 11 minutes. By April 7, the sun sets about 30 minutes later and rises about 45 minutes earlier, giving us nearly 13 hours of sun. The increase continues until the summer solstice when the sun stands over the Topic of Cancer and is above the horizon for nearly 15 hours. If I was the master timekeeper, I would lobby for a double daylight saving time starting in early May and continuing through late August. Giving us an even better fit to our waking time, sunsets would occur around 9:30 p.m., at summer solstice. However, I’m happy that we have reached this mental milestone in making the winter go away, even though as I write this article, a snowy nor’easter is raging outside. The big chill will eventually be defeated by a more direct sun angle and more daylight as Sol continues to move northward for the next several months. William Willett, an English homebuilder in London, conceived and promoted the concept of daylight saving time in 1907 with his self-publication of a pamphlet entitled, "The Waste of Daylight.” Although his ideas met with its Parliamentary champions, it wasn’t until a year after Willett’s death in May of 1916, burdened by the financial crunch of conducting WWI, that British Summer Time was enacted. Germany and Austria beat the Brits by several weeks, but one town in Canada, Port Arthur, Ontario (renamed Thunder Bay) enacted daylight saving time in 1908. The US made the switch in 1918. There is still no conclusive evidence that we actually save energy by moving our clocks ahead, but psychologically, human beings simply function better when there is more natural sunlight. Ask anyone who lives in Alaska during their long, dark, cold winters.

1125 MARCH 11, 2018: On the Cusp of Spring: I have a student by the name of Boris Bla in my Tuesday-Thursday astronomy class at Moravian who hails from the city of Abidjan in the Republic of Côte d'Ivoire (Ivory Coast) in Africa. Boris is my first equatorial African student, although I have had several Ecuadorian pupils during my public school career in the Allentown School District. Along with my numerous Saudi students who live very close to the Tropic of Cancer, talking about the seasons is a really an enjoyable experience because I have direct confirmation from the very people who live in these climes. I also have a student, Hayward Smith, who spent a semester in Australia. Talk about everything being upside-down, including the seasons; Australia’s the place. As we rapidly head towards the vernal or spring equinox on Tuesday, March 20 at 12:15 p.m., Boris’ family is about ready to be pounded by rays of sunlight that will be descending upon Abidjan from nearly the vertical. On the equinoxes the equator is center stage for the sun being overhead. Not only are the days and nights equal—“equinox” is from the Latin and means “equal night”—but the sun is transitioning from the Southern to the Northern Hemisphere. During the next six months the sun will be favoring us, moving rapidly northward over the next several weeks, then slowing its poleward climb until it reaches its peak distance from the equator, 23.5 degrees on Thursday, June 21 at 6:07 a.m. It will be the summer solstice. The word “solstice,” also translates from the Latin as “sun still” or “sun standstill.” At summer solstice it will be my Saudi’s turn to bask in the vertical rays of sunlight at local noon, but currently, Boris’ city of Abidjan, located against the warm, tropical waters of the Atlantic, is in the spotlight. At a latitude of only five degrees north of the equator, Abidjan will see direct sun on April 3, two weeks after the sun crosses the equator and our spring begins. Here at Moravian, we will only experience a chilly noontime sun altitude of 55 degrees. We are approximately 35 degrees north of Abidjan, and, of course, a great distance to the west, but it is the north-south direction that counts here. If the sun is directly at the zenith in Boris’ hometown, and he walked with his back away from Sol towards the north over the curvature of the Earth for 35 degrees to reach Moravian College’s 40-degree north latitude position, the sun would move in the opposite direction—southward 35 degrees in the sky. It seems like a straightforward enough concept, but it is a new idea for my students to grasp. The seasons are a function of Earth’s axial slant which is 23.5 degrees from the perpendicular to its orbital plane. As the Earth revolves around the sun in its yearly circuit, the Northern Hemisphere leans away from the sun in the winter, causing Sol to be lower in our skies and giving us a lesser amount of time when the sun is visible. Winter means that the sun rises to the south of east and sets to the south of west. In the summer with the sun north of the equator, the Northern Hemisphere leans inward, causing the days to be lengthened, and the sun to reach a higher altitude during the daytime. Now the sun rises to the north of east and sets to the north of west. This axial leaning inward and away from the sun has nothing to do with the Earth’s distance from Sol. We are actually closest to the sun in early January and farthest from our daystar in early July. It will still take another 45-60 days before the big transition to warmer, short sleeve temperatures arrive, but at least the sun is moving in the correct direction. Spring is upon us and that is good!

1126 MARCH 18, 2018: No Spring Break for the Spring Sky: Three nor’easters in a row, wind, and plenty of snow, and it’s almost springtime; but there are still some quick, easy, and fun things to do as the snow melts, and the ground begins to thaw and dry. First of all, I caught Venus on March 4 while bringing home some takeout from a local eatery. Driving and skygazing are probably not the best multitasking options that one can perform, but Venus was obvious as I journeyed against a bright twilight sky along a less crowded roadway. During the next several months, it will only get better. By the time you read this article, Venus should be easily noticeable in much deeper twilight. Fainter Mercury will be to Venus’ right. Twenty to 30 minutes after sundown look west, just left of the brightest area of the darkening sky. Venus should be easily seen with the unaided eye, but you will probably initially need binoculars for Mercury. Both planets will be visible all week long, Mercury to the right of the Goddess of Beauty in the twilight sky of early evening. On March 18 a very thin crescent moon joins Venus and Mercury visible in an upward slant with the moon being farthest to the left and lowest. All three objects will be visible in the same field of view using wide angle binoculars—stunning. The following evening, March 19, the moon is much higher in the sky and only five degrees to the left of Uranus. Venus and Mercury stand alone, separated by only four degrees, just slightly changed from where they were the evening before. Each set of objects will be visible in the same field of view in binoculars. Nine days later on March 28, sees Venus and Uranus only 1/10th of a degree apart in the deepening twilight of early evening. Uranus will be very, very close to brilliant Venus and just to her upper right. Binoculars will be needed to spot Uranus. This week also offers an excellent opportunity to watch the moon rapidly climb into the evening sky. This is one of the characteristics of waxing crescent moons occurring in the months surrounding the vernal equinox—February, March, and April. The celestial equator which intersects the eastern and western horizon is tilted 50 degrees to the skyline. The moon’s orbital path is currently angled at yet another 18 degrees greater than the celestial equator. Therefore, Luna rises up from the horizon at a steep angle of 68 degrees which causes the moon to gain altitude rapidly when it is a thin crescent or horned moon. Starting on March 18, when the moon, Venus, and Mercury are all near to each other in the western sky would be an excellent time to watch this phenomenon unfold. By the first day of spring on the 20th, the moon will have risen more than a third of the way up from the horizon to the zenith. A map is online at astronomy.org/StarWatch/March/index-3-18.html#3-18-18. Because of the crescent moon’s orientation to the horizon, I like to call this vernal period the time of the “smiley moon.” See if you don’t agree. All you will need to do is imagine a set of eyes. Happy spring and good observing!

1127 MARCH 25, 2018: Spring? You Must be Kidding!: Nor’easter number four is blasting away, and we are officially one day into spring. One of my friends who has a keen interest in meteorology and is a major benefactor to Moravian College’s astronomy program, David Fisherowski, made the predication that we would have a succession of these types of storms in early 2018. Thank goodness, the tempests happened in March when conditions were a little warmer. Several storms passed too far from the Lehigh Valley to create much in the way of disruptions; however, this one was just right. The period for snow, however, must come to an end even if the nor’easters decide to carry on, but Dave says we are not done yet. The sun is getting higher in our sky, and the days have lengthened to the point where any snow that falls, particularly on roadways, will not accumulate unless it is at night or the snow rates are excessive like today (March 21). Spring weather is also variable with more than a reasonable number of cloudy, dismal days, but springtime also produces nights that are crystal clear and afford observers some of the best views of the late winter sky. Take March 18 as an example. The moon, Venus, and Mercury were visible low in the west, a must-see event, but conditions had to be nearly perfect because all objects, especially the moon, were very low in the western sky. Sunset occurred under a flawlessly clear atmosphere, and all three objects were visible about 30 minutes after sundown. View my photograph at astronomy.org/StarWatch/March/index-3-18.html#3-18-18. The silvery, crescent moon was visible with plenty of earthshine, light from the nearly full Earth reflected back to us from the unlit portions of the moon, as it set behind a stand of trees that were nearly flush with the horizon. Those are common sights in the southwest, but not on the East Coast. Check out the fat, waxing gibbous moon on Wednesday, March 28, about 40 minutes after sundown. It will be near the bright star Regulus in Leo the Lion. Then look west with binoculars, and you will be able to observe brilliant Venus less than five minutes of arc from the second last planet in the solar system, Uranus. An angular separation of five minutes is about 1/6th the diameter of the full moon. Using binoculars, center Venus and make it into a clock. Uranus will be seen to the upper right, really close to Venus at the 1:30 position. On the 29th Venus is above Uranus by slightly more than one degree. The Paschal Moon is full on Saturday, March 31, at 8:37 a.m., EDT which sets the stage for Easter the following day, April 1. That March 31 full moon is also the second full moon of the month, therefore making it a blue moon too. We also had a blue moon on January 31, a double occurrence that happens every 19 years. No “April fooling,” this is a weird year. If you want to get the date of Easter correct about 80 percent of the time, try memorizing that Easter occurs on the first Sunday after the first full moon after the vernal equinox (first day of spring). If you want to get Easter’s date correct all of the time, note that Easter occurs on the first Sunday after the 14th day of the Paschal Moon on or after the 21st of March. Easter can happen as early as March 22 and as late as April 25. In 2019, Easter occurs on April 21. If you celebrate, Happy Easter!

[March Star Map]

[March Moon Phase Calendar]