StarWatch: Moravian University Astronomy

MARCH 2024

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

Current Solar X-rays:

Current Geomagnetic Field:

lunar phases

1437 MARCH 3, 2024: "Weather" the April 8 Eclipse: An old adage states that weather is what you get, but climate is what you expect. This eclipse, which is so close to home but perhaps occurring at the wrong time of the year in the spring, has put the willies into me. I have mentioned in other articles that eclipse chasing as a means of seeing different parts of the world is a wonderful way to travel, but it does have its stress factors. However for this solar eclipse, happening at a time of the year when work schedules are in full swing and vacations are future summer dreams, most enthusiasts with whom I have spoken are traveling for one purpose only, and that is to be in the shadow of the moon under clear skies on E-day. * Recently, I came across two climatological maps of the probable percentages of cloud cover along the path of totality. They made my heart sink. No place along the path of totality across the United States offered a better than 50-50 chance of seeing totality under decent conditions if enthusiasts chose to remain in one location. From the Midwest, the probability fell to about a 40 percent chance of success; from Pennsylvania through Maine, some areas had only a 15 percent chance of witnessing totality. Going to one location and hoping to get lucky for this eclipse is more than risky. No one would play a game of blackjack with the house having an overwhelming chance of winning, even if all of the rules were followed. * AccuWeather looked at the last 22 years of cloud cover across the US and came up with a more positive outlook. Southern to mid-Texas is seen as the sweet spot with the lowest chance of clouds, while Oklahoma, Arkansas, Missouri, and southern Illinois have a medium risk. At the same time, the Midwest and the Northeast are statistically predicted to have the highest probability of cloudiness at the time of totality. * Contrast that with an eclipse that can be seen from Luxor, Egypt in 2027. The yearly rainfall in Luxor is 1mm and it occurs in October. I've been to Luxor, and none of my pictures show clouds in the sky. Conditions might be hazy because of windblown dust, but totality occurs at the zenith, where airborne contaminants will be minimized. For this trip, the only stressors are the world's political situation and the complications of pointing a telescope straight up into the sky. * My friend, Adam Jones, who has a degree in meteorology and is a superb forecaster, believes that in the NE, the southern shore of Lake Ontario might provide the best chances for clear skies if a particular meteorological scenario sets up called a reverse lake-effect. Cold, dry air moving across the lake creates a clear zone immediately surrounding the lake shore before the air moves inland and is uplifted to form overcast conditions. That requires a specific positioning of high and low-pressure systems, which is far from guaranteed, but one that Adam will monitor. A reverse lake-effect would greatly reduce travel times to the path of totality. * My feelings continue to remain firm that if you are not prepared to chase this eclipse to locations where the weather will be more favorable and endure a few hardships like sleeping in your vehicle on the night before E-day, your chances of success are highly reduced. Having said that, the weather along the path of totality one year earlier, on April 8, 2023, would have been very cooperative, ensuring success for most eclipse aficionados, except for those in Texas. Go figure since the odds were in favor of Texas. Weather is what you get; climate is what you expect. Regardless of plans, I wish everyone success in viewing the last total solar eclipse that will be visible over the continental US until 2044. By looking below, readers will find a map and chart depicting the weather statistics described in this article. Adam plans his first eclipse prediction forecast on April 2. I can't wait. Ad Astra!

1438

MARCH 10, 2024: Saving Daylight Starts Now

We passed the winter solstice on December 21, 2023, overtook the latest sunrise on January 5, heard about an early spring from Punxsutawney Phil on February 2, left in the drizzle the meteorological winter on March 1, and now we are springing ahead into daylight saving time. The next stop on the express train towards summer is the vernal equinox, March 20, and finally, the pinnacle of all hills on the seasonal climb of the sun, the summer solstice or "sun still," where Sol will have reached its highest position north of the equator for the year, standing over the Tropic of Cancer. That happens on June 20, 2024. * That is still a long way from where we are now, but the beauty of the sky is that it is relentless in its forward stride. Now is that time of the year when we all begin the myth of saving daylight by setting our clocks ahead by 60 minutes. There will be no 2-3 a.m. on Sunday, March 10, which is excellent if you work an eight-hour shift during that same time period. However, the piper will be paid when we fall back an hour on the first Sunday in November. * Many people believe that when we go on daylight saving time, yes, there is no "s" in "saving," the sun goes down an hour later and comes up at the same time or even an hour earlier. That would have to be called "Miracle Extended Time." By "springing" our clocks forward by 60 minutes, we shift our daylight hours more in step with our waking hours. The sun goes down an hour later, about 7 p.m., starting March 10, but it also rises an hour later, around 7:25 a.m. on the same day. We have switched to Atlantic Standard Time, the zone one hour east of us, where the clocks are one hour later. * Daylight saving time was first adopted in Germany in 1916 to save energy and promote higher production efficiency during WWI. England followed suit in 1917, and in the US, the Daylight-Saving Act of 1917 went into effect in 1918 from the last Sunday in April to the last Sunday in September. * After the war, states were allowed to adhere to or ignore the policy, but it became official again in WWII under the synonym of "War Time." England went one step further and incorporated a "Double Summer-Time," the sun setting two hours later, thinking it would boost war production even further. After WWII, states' rights mostly won over again, allowing the clocks to move forward as a state convention and not as a federal law. The current US period is from the second Sunday in March to the first Sunday in November. Hawaii and Arizona do not observe daylight saving time, nor do the US territories of American Samoa, Guam, Northern Mariana Islands, Puerto Rico, and the US Virgin Islands. * However, 18 other states, Maine, Delaware, Ohio, Kentucky, Tennessee, South Carolina, Georgia, Florida, Alabama, Mississippi, Louisiana, Minnesota, Montana, Idaho, Washington, Oregon, Colorado, and Utah, have enacted legislation/resolutions for year-round daylight saving time. California has passed a voter resolution to the same effect. This year, the Sunshine Protection Act, which would make daylight saving time the new permanent standard time, has yet to be reintroduced in the Senate or the House. * Does daylight saving time reduce energy and, therefore, cut costs? The answer is probably not because the extra hour of sunlight gained at the end of the day with later sunsets is stolen from the morning hours when most people are already awake and getting ready for work. Safety issues raised by children waiting at bus stops in the dark during the winter months have also proven inconclusive. * Happy daylight saving time! It is another milestone reached and passed on our way to those lazy, hazy, smoke-filled days of summer with their uptick in forest fires and hurricanes created by an ever-warming planet. Okay, try to stay positive, Gary. "School's out for summer. School's out forever," at least according to Alice Cooper. Ad Astra!

1439 MARCH 17, 2024: Spring, a Good Name for this Season: I cannot say it is my favorite day of the year, but the beginning of spring is when things are literally springing up. My daylilies, the local deer population find so scrumptious during the summer months, have climbed skyward from their winter hibernation and are now hovering at six-inches above the ground. And yes, the weeds are also looking up in a garden that will wow the neighborhood in just three months until the deer do their feasting. * The reason for this hoopla is the sun, climbing at its steepest angle higher into the sky. It will cross the celestial equator, heralding the vernal equinox on Wednesday, March 19, at 11:03 p.m. EDT. On the vernal equinox, it will rise due east and set due west, but after that date, Sol chooses our space, the Northern Hemisphere, rising and setting to the north of east and to the north of west, respectively. Each day until the summer solstice, the sun will be higher in the sky, its insolation (energy) increasing as its vitality is focused more directly onto the landscape it illuminates. Mid and northern latitudes will take a while to respond because they have been chilled by winter's low, indirect sunlight and much shorter days. This lag of the seasons will give way to more reliable temperatures during May, the transition month for warmer weather in our area. This same seasonal lag keeps September and October reasonably tolerable; however, by Halloween, and particularly Thanksgiving, there is no return from winter's cold onset. * In addition to the more northern rising and setting positions of the sun, the length of the path that the sun traverses from rising to setting increases daily until the summer solstice (sun still), giving way to more extended periods when Sol is visible in the sky. The effect of a higher sun and more extended periods of sunlight eventually creates the dog days of summer when many of us stay indoors to avoid the sultry conditions of summertime's highest temperatures. * The cause is the 23-1/2-degree tilt of the Earth's axis to the perpendicular of its orbital plane. For the sake of simplicity, let's say the Earth's axial tilt is 23.5 degrees. This causes the rotational plane of Earth, the movement that gives us day and night, bisected between the poles by the equator, to be at a 23.5-degree slant to Earth's orbital plane around the sun. As Earth circles our daystar, Sol must gradually move above and below the equator to a limit of 23.5 degrees north, the Tropic of Cancer, and 23.5 degrees south, the Tropic of Capricorn, a total range of 47 degrees. The low sun for the Lehigh Valley is at 26 degrees above the horizon on the winter solstice when the sun stands over Capricorn, and Earth is nearly at its closest distance to Sol. The changing distance of Earth from the sun is not responsible for our seasonal variations. * Approximately six months later, it is positioned 47 degrees northward over Cancer, and the sun has climbed 47 degrees higher in the Lehigh Valley to 73 degrees. Currently, Sol is moving northward at its greatest clip. Watch how the amount of daylight rapidly expands over the next several weeks. * Happy Spring. It's a new season, our time under the high sun, until the autumnal equinox. Ad Astra!

1440 MARCH 24, 2024: Penumbral Lunar Eclipse, March 25: There is a curious fact about solar and lunar eclipses. You cannot have one without the other. That's partly because the moon, the sun, and the Earth's shadow are not point sources, so there is ample leeway for projected shadows to be intersected by the Earth and the moon to create solar and lunar eclipses. The five-degree tilt of the moon's orbit to the ecliptic is also an essential factor. The ecliptic is the plane of the Earth's orbit projected into space. Because of the moon's slight inclination, it can cross the ecliptic as far away as 18 degrees, 31 minutes from the sun to produce a partial solar eclipse, and as far as 11 degrees, 50 minutes from Sol to create a total solar eclipse. * A crossing position is termed a node in astronomy. A partial solar eclipse must occur if the moon's node is less than 15 degrees, 21 minutes from the sun, and a total solar eclipse is assured if the moon's node lies under 9 degrees, 55 minutes from the sun. Where they are visible from Earth is a whole other story. The essence is the alignments for solar and lunar eclipses don't have to be perfect. * Because of the shallow inclination of the moon's orbit to the ecliptic and the ever-changing distances of the Earth from the sun and the moon from the Earth, solar eclipses can come in a whole variety of different forms: total, partial, annular (ringed), broken annular (moon surrounded by Baily's beads), and hybrid (part of the path ringed and part total). I have had the good fortune to have witnessed every type. * Lunar eclipses, where the moon hides in the shadow of Earth, can also be total and partial, as well as penumbral and partial penumbral. If observers are in the penumbra of the moon's shadow for a solar eclipse, they witness part of the moon covering part of the sun. That is the location of the Lehigh Valley on April 8. * For penumbral lunar eclipses, it is better to imagine an astronaut on the moon looking back at the Earth. The individual would observe a partial solar eclipse with part of the Earth covering part of the sun. From Earth, observers would witness a diminution of the sun's light falling on the lunar surface, a greying of Luna's landscape, darkest where the moon would be closest to the actual shadow of Earth, the umbra. * During the early morning of Monday, March 25, there will be a deep partial penumbral eclipse of the moon. It begins at 12:53 a.m. EDT and concludes at 5:32 a.m. EDT. The beginning and ending of penumbral eclipses are nonevents. They represent the moment of tangency of the moon's surface with the penumbra. The most easily witnessed part of the eclipse will happen at 3:13 a.m. EDT, when the southern hemisphere of the moon, the area of Luna that appears much brighter because it contains fewer lava-inundated seas (maria), will be closest to the Earth's primary shadow. That will be easily noticeable to the unaided eye, and for me, hopefully outside with my camera and telescope under clear skies, a wonderful precursor of better sights to come. See the egress penumbral portion of the December 21, 2010 total lunar eclipse below. Ad Astra!

1441 MARCH 31, 2024: Binocular 12P/Pons-Brooks in Evening Twilight: I am ever so reluctant to talk about comets in the sky because as everyone knows, "Comets are like cats: they have tails, and they do precisely what they want." That is the best summarization of binocular comets that I have ever found. Its author is longtime comet discoverer David H. Levy, who penned this sentence in his book, Comets: Creators and Destroyers. I had the pleasure of visiting David and his wife, Wendee, at their home outside of Tucson, Arizona in 2000, observing with him, and inviting him to be the guest speaker at an anniversary banquet of the Lehigh Valley Amateur Astronomical Society. * Levy is one of the world's most successful comet discoverers, having netted 22 in all, including Comet Shoemaker-Levy 9, along with Caroline and Eugene Shoemaker in 1993. In mid-July of 1994, Shoemaker-Levy 9 collided with Jupiter in one of the most spectacular solar system events ever recorded. * As successful as Levy has been in the comet detection business, he can't hold a candle to the record holder, French astronomer Jean-Louis Pons, who found 37 "hairy stars" between 1801 and 1827. He first saw the comet that bears his name at the Marseilles Observatory in July 1812. It was rediscovered by the British-born American astronomer, William Robert Brooks, on its subsequent return to the sun in 1883. Ironically, Brooks is the second most prolific comet discoverer, having notched his comet belt 27 times between 1881 and 1912. * The "12P" in Comet 12P/Pons-Brooks means that it was the 12th periodic comet cataloged. Periodic comets return to the sun in timescales of less than 200 years. In the case of Pons-Brooks, its orbital period is 71.20 years. * The Pons-Brooks buzz is that observers will be able to view it during the April 8 total solar eclipse because it will be close to Jupiter in the sky and therefore, easy to locate. Stay calm about this bogus media prediction if you are headed to the centerline because Jupiter, which should be very easy to spot during totality, will outshine 12P/Pons-Brooks by about 300 times. Unless some extraordinary event brightens Pons-Brooks during this week, umbraphiles should focus their attention on the eclipsed sun and what should be a very elongated and spectacular corona. * However this week, the planet Jupiter and Hamal, the brightest star of the zodiacal constellation Aries the Ram, will help guide observers to this binocular object low in the WNW about 45-60 minutes after sundown. * A suburban-to-rural observing location with a reasonable western horizon will be necessary. The time after sundown will also be critical because Pons-Brooks will only be about 10 degrees above the horizon, giving it a short window of viewing opportunity before it sets. Ten degrees is about the angular distance a clenched fist subtends with the thumb on top held at arm's length. * Once Jupiter is found, the comet will be positioned about three binocular fields of view to the right and down. This week, particularly on the nights from March 31 through April 2, 12P/Pons-Brooks will lie close to the second-magnitude star, Hamal. Keep in mind that Hamal is about as bright as the stars in the Big Dipper, but it will appear much fainter because of its nearness to the horizon. Through binoculars, the comet should look like a fuzzy cotton ball with a small upward pointing tail. As the week progresses, 12P/Pons-Brooks will be moving towards Jupiter so that by the time of the eclipse, it will lie between Hamal and Jupiter in the heavens. I first saw 12P/Pons-Brooks on March 20 in a bright moonlit sky as a faint, fuzzy elongated object with about a half-degree tail. My second attempt on March 25 proved unsuccessful. Much success in locating the brightest comet visible in several years. Ad Astra!