Julian Date: 2459311.18
2020-2021: CVIII
THE DAILY ASTRONOMER
Tuesday, April 6, 2021
April 2021 Night Sky Calendar Part III
TUESDAY, APRIL 20: MOON NEAR BEEHIVE STAR CLUSTER
The image below shows the Beehive star cluster as it would appear in a time-exposure photo, one in which the light is allowed to accumulate over time so as to produce a meticulously detailed image:
In our sky, Praesepe, or the "Beehive Star Cluster," appears as a faint smudge of light at the center of the constellation Cancer the Crab. The moon will often appear to draw close to the Beehive star cluster because Cancer, being a zodiac constellation, is aligned along the ecliptic, the band through which the moon moves. Like the Pleiades, Praesepe is a galactic star cluster, though a bit farther away at a distance of 577 light years.
See the first quarter moon (50% illuminated) close to Praesepe tonight.
THURSDAY, APRIL 22: LYRID METEOR SHOWER PEAKS (GOLD EVENT!!!)
Tonight watch as approximately 20 - 45 meteors an hour appear to emanate from a region surrounding Lyra the Harp, hence the name "Lyrids." As the moon will be in the waxing gibbous phase, viewing conditions will not be ideal in the early evening. However, the best time to observe meteors is after midnight, at which time our part of the planet will be turning into the meteoroid stream.
The parent comet is C/1861 GI Thatcher. It is this comet that cast off the dust particle clouds through which Earth is presently traveling. When these particles, called meteoroids, pass through the planet's upper atmosphere, they excite the surrounding atoms to higher energy states. When these atoms return to their original low energy configurations, they emit photons we see as meteors.
Even if one misses the peak event tonight, one can still see Lyrids during the following week. The Lyrid shower begins on April 14 and ends on April 30th. Tonight, Earth moves through the densest part of the meteoroid stream.
THURSDAY, APRIL 22: MOON NEAR REGULUS
Tonight, the waxing gibbous moon (73% illuminated) appears to move close to the bright star Regulus, the alpha star in Leo the Lion. The gibbous moon will be located just north of Regulus, which marks the southern "point" in the lion's sickle, or backward question mark.
FRIDAY, APRIL 23: HERCULES UP SOON AFTER SUNSET
Hercules is known as the "kneeling one," because the constellation is depicted as kneeling on Draco's head. Hercules ascends into the eastern sky soon after sunset and will remain visible all night. The most prominent aspect of the Hercules' constellation is the 'keystone,' a quadrilateral of stars that represents the warrior's mid-section.
One of the best ways to find Hercules is to first find the Big Dipper. Follow the handle's arc down to the star Arcuturs (remember the mnemonic, "Arc to Arcturus"). Arcturus is the brightest star in Bootes the Sheepherder. Corona Borealis, the "northern crown," is just to the east of Bootes. As one can see in the above image, Corona Borealis is also just to the southwest of Hercules' keystone.
So, find the Big Dipper => follow the handle's arc to Arcturus => move east to Corona Borealis and then to Hercules.
MONDAY, APRIL 26: MOON NEAR SPICA
The waxing gibbous moon (99% illuminated) passes close to Spica, the brightest star in Virgo the maiden. If nothing else, these monthly lunar appulses might help one to identify some of the sky's brightest stars.
TUESDAY, APRIL 28: FULL MOON (SUPER MOON!)
We recall that the Super Moon is defined as a moon that is full when it is also at or near perigee, the point of least distance from Earth. Tonight, the moon is full and at perigee, as well. In fact, the moon reaches perigee about twelve hours after it reaches opposition (becomes a full moon.) The Super Moon is 30% brighter than 14% larger than the Micro moon, defined as the full moon that occurs when the moon is at or near apogee, its point of greatest distance from Earth.
The above image shows both a Super Moon and a Micro Moon. The Super Moon is 30% brighter and 14% larger than a Micro Moon.
WEDNESDAY, APRIL 29: MOON NEAR ANTARES
See the waning gibbous moon (91% illuminated) close to Antares, the brightest star in Scorpius the Scorpion. See them both traveling through the southern sky after midnight.
PLANET WATCH
MERCURY
Host constellation (early month): Pisces
Host constellation (late month): Aries
One will find Mercury in the early morning sky at the beginning of the month. By mid-month, Mercury vanishes into the pre-dawn glow and will be lost to sight for the rest of April. VERDICT: The earlier the better. Mercury-seekers should venture out sometime during the first ten days of April to find the first world in the early morning eastern sky.
VENUS
Host constellation (early month): Pisces
Host constellation (late month): Aries
Venus is exceedingly difficult to find for most of April. By month's end, one might just glimpse our sister world low in the early evening western sky. VERDICT: Don't bother searching for Venus until the end of April. Even then, one will have to go out soon after sunset to find it. Good news: Venus will become easier to find in May and throughout the rest of spring and summer!
MARS (PICK PLANET!)
Host constellation (early month): Taurus
Host constellation (late month): Gemini
Even though Venus will make an appearance late this month, Mars essentially has the evening sky stage to itself. At magnitude 1.4, Mars is about as bright as Regulus, the brightest star in Leo the Lion. At month's beginning, Mars sets about forty minutes after midnight. At month's end, Mars will set a few minutes after midnight. VERDICT: Still moderately bright, Mars remains an easy evening sky sight throughout April. Seek it out before midnight in the western sky.
JUPITER
Host constellation (early month): Capricornus
Host constellation (late month): Aquarius
Although Jupiter will be rising progressively earlier each day, it remains a morning sky object all month. At the beginning of April, Jupiter rises around 4:45 a.m. At month's end, Jupiter rises at 3:00 a.m. Jupiter brightens throughout April: magnitude -1.9 on April 1st and -2.1 on April 30th. Throughout the month, Jupiter will outshine Sirius, the night sky's brightest star. VERDICT: Jupiter is a perfect planet for early risers. It will be easier to find later this month.
SATURN
Host constellation: Capricornus
At magnitude 0.8, Saturn is about twelve times dimmer than Jupiter, it rises earlier and might be easier to find. On April 1st, Saturn rose at 4:08 a.m. On April 30th, the sixth world will rise around 2:15 a.m. VERDICT: Saturn is rising into greater prominence and so will be easy to spot, especially later in the month.
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