Look for this meteor shower just before midnight on these two nights. There is a good chance of seeing a hundred or more meteors per hour! The radiant (the apparent point of origin) is in the constellation Gemini, which will be high overhead as midnight approaches. Be sure to get some observing in before the Moon rises at about 11pm and midnight on these two nights.
Look for this meteor shower at around midnight on these two nights. The radiant (the apparent point of origin) is in the constellation Leo, which will be high overhead at midnight. Interestingly, at any given time of the year, the Earth is moving toward whatever stars happen to be directly overhead at midnight, and it “smashes” into the debris field that crosses the Earth’s orbit and creates the shower.
The Leonid shower of 2002 was the best meteor shower that I have ever witnessed. I went out at around midnight near the peak, and the origin was nearly directly overhead. I could see about six to eight meteors per minute that seemed to fly out of the origin in all directions. While lying on my back and looking straight up at the origin the visual effect was very much like the old Windows screen saver that gave the appearance of flying through a star field.
For the second month in a row, the full Moon will be a supermoon. This is also known as a perigean moon. A supermoon is said to occur when the Moon is full at the same time it is near perigee, which is its closest approach to Earth during its monthly orbit.
When two Solar System objects arrive at their closest approach to one another as viewed from Earth, they are said to be in conjunction. This month I will examine the Moon’s close approaches to all five of the visible planets that were known to the ancients. As both the Moon and the planets are in constant motion, the actual conjunction is represented by an instant in time. Because of their slow apparent motion, the close approaches (visits?) can be observed for many hours before or after a conjunction.
As previously mentioned, the planets and the Moon never wander far from the ecliptic. One implication of this fact is that as the Moon completes its 28-day orbit around the Earth, it will be in conjunction with each of the planets once. This month, the young (thin) crescent Moon will first visit Jupiter near the western horizon in Gemini on May 3rd (closest) and 4th. Try to observe on both evenings and note that the Moon has moved eastward. Also note Jupiter’s position among Gemini’s stars, perhaps by making a sketch of Gemini that indicates Jupiter’s position. This sketch will come in handy near the end of the month.
Next up is a very interesting series of close encounters with three bright and colorful objects (Mars, Spica and Saturn) in the east at dusk on May 10th through the 14th. There are lots of things to observe over the course of these five evenings. First, the waxing gibbous Moon will grow larger each evening until it reaches full Moon on May 14th. Next, note that its location is a little farther east each evening. These two phenomena are the result of the Moon moving along its orbital path around the Earth, which changes its angle relative to the Sun. Also note that the point at which the Moon became full last month was closer to Mars (read about the lunar eclipse in April’s Scope Out), and this month the full Moon occurs closer to Saturn. This eastward slide of the full Moon from one month to the next happens because of the Earth moving along its orbital path around the Sun. And finally, note the distinct colors of the three objects: Mars is red, Spica is blue, and Saturn is yellow. The Moon will be near Mars on May 10th, and between Mars and Spica on May 11th. It will be between Spica and Saturn, but closer to Spica on the 12th, and closer to Saturn on the 13th. And finally it will be on the eastward side of Saturn on May 14th, the last evening of this string of encounters.
Another rewarding and challenging opportunity to observe the Moon arrives near month’s end as it transitions from a thin waning crescent in the eastern sky at morning, to a thin waxing crescent in the evening sky in the evening. First, observe the Moon as a thin waning crescent on the eastern horizon during its close encounter with Venus just before sunrise in the pre-dawn hours of May 25th. A careful observer might see an even thinner crescent very low on the horizon and closer to the sunrise point the next morning. After this, the Moon cannot be seen because it is lost in the Sun’s glare as it approaches new Moon (conjunction with the Sun) on May 28th. A young Moon (thin waxing crescent) emerges from the Sun’s glare on May 30th, and can be seen very low on the western horizon near Mercury. On the next evening, it will appear a little higher above the horizon, and it will once again visit Jupiter. Check the sketch that you made at the beginning of the Month. Has Jupiter moved among the stars since its last visit with the Moon on May 3rd and 4th?
Earth is predicted to pass through the path of Comet LINEAR on May 24th. LINEAR is a small comet that was discovered just a decade ago. It has a relatively short period, returning to the inner Solar System every five years, and travelling no farther away from the Sun than Jupiter. As a result of LINEAR’s orbit being perturbed during its last encounter with Jupiter, the path of its orbit now crosses the path of Earth’s orbit. Meteor showers occur when Earth crosses the orbital path of a comet, because stony debris are left behind as the icy comet evaporates when heated by the Sun. Since this is Earth’s first pass through this rather compact debris field, some astronomers are predicting a brief but spectacular meteor shower that begins at 2am on May 24th. Look for the peak, the highest number of meteors per hour, at around 3am, and the shower should subside by 4am. To observe, a darker sky is better because fainter meteors can be seen. The origin is near Usra Major’s ‘nose’, so watch a point about half way between the origin and the zenith (the point directly above your head). Be sure to dress warmly and sit in something comfortable, like a reclining lawn chair.
Named meteor showers occur at roughly the same time each year. Astronomers estimate that the this year’s shower will be somewhat subdued because the Moon brightens the sky, which prevents the dimmer meteors from being seen. All of the meteors associated with the Lyrids shower will appear to come from inside the constellation Lyra. Even though the visible meteor trails are likely to begin outside of Lyra, and the end of the trails will be even farther away from Lyra in every direction, all of visible meteor trails associated with this shower can be traced backward to a common point within Lyra. The shower begins around April 16th and occurs every night through about April 25th. The shower will peak (highest number of meteors per hour) on April 22nd and 23rd. Lyra will rise in the east at about 11:30pm during this period, and can be found by locating its bright star Vega using a planisphere or smartphone app. To observe, be sure to dress warmly and sit in something comfortable, like a reclining lawn chair.
The full Moon occurs when the Moon is at the point in its orbit on the side of the Earth opposite the Sun. Another way of describing this, is to say that the Earth is directly between the Sun and Moon when the Moon is full (fully lit). The Earth, like all objects upon which sunlight falls, the casts a shadow. This shadow extends into space in the Moon’s direction at full Moon. The Moon usually misses the Earth’s shadow by passing just a little above or below it at full Moon. But the Moon will pass through the Earth’s shadow this month in the early morning hours of April 15th. The Moon enters the penumbra (the lightest part of the Earth’s shadow) at 12:37am EDT, but the best viewing begins at about 2am when the Moon enters the umbra (the darkest part of the Earth’s shadow). Totality occurs when the Moon is completely inside the umbra from 3:06am until 4:27am, at which time it begins to re-enter the penumbra. This stage of the eclipse is the beginning of the Moon’s exit from the Earth’s shadow. The Moon completely exits the umbra at 5:30am, and the eclipse is completely over when the Moon exits the encumbrance at 6:30am.
There are two really neat things to note about the eclipse. First, the “sunset” effect. The portion of the Moon within the umbra will have a distinct reddish cast as a result of the Sun’s rays passing through the edges of the Earth’s atmosphere. As the eclipse progresses, the umbra can first be seen on the eastern edge of the Moon. Over the next hour or so, the portion of the Moon covered by the umbra will grow larger, until the Moon is completely engulfed by the umbra. The reverse will occur as the Moon slides back out of the umbra. Here’s the other neat thing to note. What the observer is actually watching as the Moon passes through the Earth’s shadow is the Moon moving along it’s orbital path around the Earth.
Events come and go, but are interesting to observe. Event durations can vary from an instant to seconds, minutes or days, or even longer. Examples include eclipses, certain planetary arrangements and alignments, meteor showers, and transits of the Sun. One must know when, where, and how to observe an event in the night sky. Most events covered in Jim Johnson’s Astronomy provide insight into how the Solar System actually works.