What's Up in the Night Sky

April 2022 - Vol. 26, No. 4

This Month's Night Sky - NOTE: The next paragraph describes the sky as it appears at 10 pm EST (11 pm EDT) near mid- month. The sky also looks this way at 11 pm EST (midnight EDT) during the beginning of the month and at 9 pm EST (10 pm EDT) by month's end.

As the days lengthen, the stars of the Winter Triangle fade into evening's dusk. The "Big Dipper" asterism (Ursa Major) is well placed for viewing this month since it is almost directly overhead. Follow the curve of its handle to Arcturus (Bootes) and continue on the curve to Spica (Virgo). Regulus (Leo) is on the ecliptic (the path traced by the planets and Moon), just W. of overhead. Further W., on the ecliptic, find the Gemini Twins, Castor and Pollux, and finally the Pleiades asterism of Taurus.

MERCURY is at superior conjunction on the 2nd, bursting into the evening sky mid-month opening the best apparition for northern observers this year. VENUS in the morning sky continues its waltz with Saturn and Mars, although she has already left them behind. MARS in Capricornus will be shining at +0.9 mag by month's end. Mars overtakes Saturn on April 4, passing .3 deg. south of the ringed planet. JUPITER moves into Pisces and has a close conjunction with Venus on April 30. SATURN in the morning sky rises around 2:30am as the month ends. URANUS in Aries, sets in the evening sky. NEPTUNE has a conjunction with both Venus (April 27) and Jupiter (April 12) this month, it will take a telescope to view both events.

Review how to determine Angular Measurement.

Calendar of Events

NOTE: For those observers not in the ET zone, convert the calendar times to your zone's time by subtracting one hour for CT, two for MT and three for PT. Don't forget to adjust for Daylight Savings Time when necessary by subtracting one hour from your planisphere's time. Dawn and dusk times must also be corrected. See your local newspaper, TV news, or cable TV's Weather Channel for sunrise and sunset times or check with the U.S. Naval observatory. Unfortunately some of these events may occur during daylight hours in your area.

DATE	EVENT
02	Mercury at superior conjunction.
03	Uranus .6 deg. N of Moon, occultation from E. S. America, Ascension Island, St. Helena, edge of W. Central Africa.
04	Mars .3 deg. S. of Saturn.
06	Ceres 0.2 deg. N. of Moon, occultation from Madagascar, parts of Eastern Africa, S. and E. India, most of SE Asia, SE China, Papua New Guinea, and Micronesia.
07	Moon at apogee.
09	Mercury at ascending node.
10	Venus at descending node.
12	Jupiter 0.1 deg. N. of Neptune.
13	Mercury at perihelion.
18	Mercury 2 deg. N. of Uranus.
19	Moon at perigee.
22	Lyrid Meteor peak. The shower is estimated to contain 20 meteors at peak, this year the Moon rises in the early morning with 62% of the disk illuminated.
24	Mercury at greatest heliocentric latitude N. Saturn 5 deg. N. of Moon.
25	Mars 4 deg. N. of Moon.
27	Venus 4 deg. N. of Moon. Jupiter 4 deg. N. of Moon. Venus .01 deg, S. of Neptune.
29	Mercury at greatest elongation E. (21 deg.) Mercury 1.4 deg. S. of Pleiades (M45)
18	Venus at greatest elongation W. (47 deg.) Jupiter. (not visible)
30	Venus .2 deg. S. of Jupiter. Partial solar eclipse, Sun 64% covered by Moon visible over remote South Pacific off coast of S. America.

Lunar Almanac for April 2022

Phases of the Moon	Phase and Date(s)	Best viewed before local midnight
	New 01, 30	Deep Space Objects
	1st. Qtr 09	Planets & Moon
	Full 16	Moon
	Last Qtr 23	Deep Space & Planets

Topic of the month: Canes Venatici: Dogs of the Northern Sky

The northern sky is a dark place, far from the bright star clouds of the Milky Way. Here be dragons, bears, and hunters. The northern hunters also brought their hunting dogs, in the form of a little constellation known as Canes Venatici. This constellation was introduced by Johannes Hevelius in 1690. Visually, the constellation appears to the naked eye as two stars beneath the the handle of the "Big Dipper", the brighter of the two is known as Cor Coroli, or heart of the king. It is a 2.9 magnitude star accompanied by a 5.5 magnitude companion located about 150 light years away. This double star is very easy to detect in a small telescope. The fainter star is called Chara, a yellow 4.3 magnitude star.

finder chart for Canes Venatici

Canes Venatici is near the north galactic pole of the Milky Way. Because of its position, it is the home of many external galaxies, the brightest Messier galaxies can be located by using the finder chart. The most famous galaxy in this part of the sky is known as M51,also known as the Whirlpool galaxy, actually a pair of interacting galaxies (NGC 5194 and 5195) that are best observed in a larger telescope, 10 inches or better. Its spiral structure was first observed by Lord Rosse using a 72-in telescope in 1845. At mag 8.4 it is bright enough to be seen by smaller instruments, even binoculars, but it will appear as a fuzzy patch.

The galaxy M63, near an 8th mag star is tilted about 30 deg from face on, is sometimes called the "Sunflower" nebula. Another bright galaxy in Canes Venatici is M94, another face on spiral. this galaxy has a large central bulge and is tightly wound and will appear as a round object at a dark site. The last Messier galaxy on this chart, M106 is also a Seyfert galaxy, that emits x-rays.

Another feature of Canes Venatici is the globular star cluster M3, that is not seen in the chart above that was generated by Stellarium, a free open source planetarium program. The above image was created by Dawn Jenkins, using Stellarium and a graphic editing program. The globular M3 is found on a line between Cor Coroli and Arcturus.

The dark galactic pole must share the night with the star clouds of the northern Milky Way, that rise into the night sky just before midnight at the beginning of the month.. The bright presence of those clouds of galactic stars and dust will make it hard to find the dark galaxies of Spring as we move into Summer.

--See You Under the Stars!
Astra for Astra's Almanac