THE SOUTHWORTH PLANETARIUM 70 Falmouth Street Portland, Maine 04103 (207) 780-4249 usm.maine.edu/planet 43.6667° N 70.2667° W Altitude: 10 feet below sea level Founded January 1970 2021-2022: CIV "No problem can withstand the assault of sustained thinking." -Voltaire THE DAILY ASTRONOMER Tuesday, April 5, 2022 April 2022 Night Sky Calendar Part II * SUNDAY, APRIL 17: EASTER!* Well, yes, indeed, it is an astronomical event, as well as being an ecclesiastical one. Easter, as determined by the Council of Nicaea in AD 325, occurs on the first Sunday after the first full moon occurring on or after the equinox. Consequently, Easter can happen on any date between March 22 - April 25. Granted, Easter rarely occurs on these extreme dates. One would have to either propel oneself back to 1818 or forward to 2285 to experience the most recent or the next March 22nd Easter. On the other hand, the last April 25th Easter happened in 1943 and the next one occurs in 2038. At times, the dates for astronomical and ecclesiastical Easter differ because by ecclesiastical reckoning, the vernal equinox invariably occurs on March 21st. Astronomically, the equinox can occur on March 19, 20 or 21st. These Easters are termed "paradoxical," despite the fact that we know precisely why they occur. Paradoxes, such as "Every statement I make is a lie including this one," tend to be annoyingly irreconcilable or inexplicable. We know full well why in some years astronomers celebrate Easter on a different Sunday than the clergy. (Will they ever get along?) *TUESDAY, APRIL 19: MOON AT PERIGEE* The moon reaches its closest point in this orbit: 365,143 kilometers, today! Is there, perhaps tucked away on page 1,578 of an esoteric astronomical tome that nobody has consulted since Copernicus was a corporal, a term denoting a perigean almost full moon occuring on or around Easter? Well, if there is such a term, we're going to cheerfully ignore it, thank you very much. We cannot consider this month's full moon to be a *SUPER MOON, *because the perigee date occurs three days after opposition, the time when the moon is full. A *SUPER MOON*, which we're writing in bold print and all capitals in order to ensnare hapless readers, can only occur when the perigee happens within two days of opposition. Add that extra day and the *SUPER MOON* becomes a good old fashioned mortal moon that doesn't mind kryptonite, but always flees at the first sign of danger. *THURSDAY, APRIL 22: LYRID METEOR SHOWER (GOLD EVENT!!!)* Tonight, the Lyrid Meteor Shower, one of the year's "major showers," peaks. Observers can expect 10 - 20 meteors an hour. Unfortunately, the gibbous moon (60% illuminated) rises at 11:54 p.m. Since meteor showers are best observed after midnight, the time when our part of the world turns into the meteoroid stream, the lunar light interference will hinder our viewing. We understand why so many people venture outside solely to observe meteors. They are, after all, night sky pyrotechnics. While they hardly make a sound, they tend to be dazzlingly bright, produce trails and, on occasion, explode in a fiery burst of blinding incandescence. The origin of meteor showers is just as fantastical as their appearance. They are produced when our Earth, which is whipping around the Sun at 67,000 miles an hour -about 30 times faster than a Mach 3 missile- plows through a stream of particles cast off by a comet. The Lyrid's parent comet, C/1861 Thatcher, follows a long, lazy 422-year orbit. It last swooped by the inner solar system in -you guessed it!- 1861 and is due for a return visit in 2283. Unless, of course, its orbit is perturbed by a major planet, or it slams headlong into the armada of mid 23rd century spacecraft conveying survivors away from the global nuclear exchange that science fiction authors have been promising us for years. HINT: try to look for the Lyrids an hour before midnight, prior to the moon's ascent above the horizon. *FRIDAY, APRIL 23: LAST QUARTER MOON* * SUNDAY, APRIL 25: MOON NEAR SATURN* Poor Saturn and Mars: sharing the morning stage with Venus, which dazzles the eyes, delights the soul, beguiles the senses and, frankly, makes a gaudy display of herself. Meanwhile, Mars and Saturn, both of which are 91 times dimmer than Venus, cower in her shadow, enticing nobody. Well, today, one can use the waning crescent moon (27% illuminated) to help find Saturn. Look for the moderately bright light just above the crescent moon. *MONDAY, APRIL 26: MOON NEAR MARS* You used the moon to find Saturn yesterday. Use it to find Mars today. See the waning crescent moon (18% illuminated) just to south of Mars this morning. *THURSDAY, APRIL 29: MERCURY AT GREATEST EASTERN ELONGATION* Darn it, Mercury is a swift mover, isn't it? Recall that Mercury just passed into superior conjunction on April 2 and now it has attained its greatest elongation in the western evening sky! While this is the best time to seek out Mercury, be aware that the first world always nestles close to the Sun and so remains difficult to observe! *FRIDAY, APRIL 30: NEW MOON (BLACK MOON AND PARTIAL SOLAR ECLIPSE!)* First and foremost, alas, we will not observe this partial solar eclipse, which is only visible from the southeast Pacific and southernmost regions of South America. However, this eclipse is associated with the TOTAL LUNAR ECLIPSE that will occur on May 15/16th, which we will certainly be able to observe, provided, of course, that the skies are clear. *FRIDAY, APRIL 30: VENUS 0.23 DEGREES SE OF JUPITER (SILVER EVENT!!)* Oh, this will improve Mars' and Saturn's self esteem. Now, Venus and Jupiter, the two brightest planets, appear close together in the pre-dawn eastern sky. See gorgeous Aphrodite and her handsome companion Zeus ascending hand in hand above the brightening morning twilight! Even though Jupiter outshines all the night sky stars, Venus remains more than six times brighter! All the same, Jupiter has no cause for shame. Just look at Mars and Saturn. Tomorrow, April 2022 Night Sky Calendar Part III: April Stars and Planets To subscribe or unsubscribe from the Daily Astronomer: https://lists.maine.edu/cgi-bin/wa?SUBED1=DAILY-ASTRONOMER&A=1