Post by Dave Mitsky on Apr 2, 2022 4:03:08 GMT
April Celestial Calendar by Dave Mitsky
All times, unless otherwise noted, are UT (subtract four hours and, when appropriate, one calendar day for EDT)
4/1 New Moon (lunation 1228) occurs at 6:24
4/2 Mercury is in superior conjunction at 23:00
4/3 The Moon is 0.6 degrees south of Uranus, with an occultation taking place in a portion of western central Africa, St. Helena, Ascension Island, and southern and eastern South America, at 17:00
4/4 Mars is 0.3 degrees south of Saturn at 22:00
4/6 The Moon is 0.2 degrees south of the dwarf planet/asteroid 1 Ceres, with an occultation taking place in most of Micronesia, Papua New Guinea, southeastern China, most of southeastern Asia, southern and eastern India, parts of eastern Africa, and Madagascar, at 9:00
4/7 The Moon is at apogee, subtending 29' 33'' from a distance of 404,436 kilometers (251,306 miles), at 19:11
4/8 The Lunar X (the Purbach or Werner Cross), an X-shaped illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to be visible at 20:20
4/9 Mercury is at the ascending node today; First Quarter Moon occurs at 6:48
4/10 Venus is at the descending node today
4/12 Asteroid 2 Pallas is in conjunction with the Sun at 3:00; Jupiter is 0.1 degrees north of Neptune at 20:00
4/13 Mercury is at perihelion today
4/16 Full Moon, known as the Egg, Grass, or Pink Moon, occurs at 18:55
4/18 Mercury is 2 degrees north of Uranus at 13:00
4/19 The Moon is at perigee, subtending 32' 44'' from a distance of 365,145 kilometers (226,890 miles), at 15:13
4/22 The peak of the Lyrid meteor shower (15 to 20 meteors per hour) is predicted to occur at 18:00
4/23 Last Quarter Moon occurs at 11:56
4/24 Mercury is at its greatest heliocentric latitude north today; the Moon is 5 degrees south of Saturn at 21:00; the Curtiss Cross, an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart, is predicted to be visible at 22:11
4/25 The Moon is 4 degrees south of Mars at 22:00
4/27 The Moon is 4 degrees south of Venus at 2:00; the Moon is 4 degrees south of Jupiter at 8:00; the Moon, Venus, and Jupiter lie within a circle with a diameter of 4.1 degrees at 9:00; Venus is 0.007 degrees south of Neptune at 19:00
4/29 Mercury is at greatest eastern elongation (20.6 degrees) at 8:00; Mercury is 1.4 degrees south of the bright open cluster M45 (the Pleiades or Subaru) in Taurus at 19:00
4/30 A partial solar eclipse visible from far northern Antarctica, southern South America, and the southern portions of the Pacific and Atlantic Oceans begins at 18:45 and ends at 22:38; Venus is 0.2 degrees south of Jupiter at 19:00; New Moon (lunation 1229) occurs at 20:29
Charles Messier discovered the open cluster M50 in Monoceros on April 5, 1772. Charles Messier discovered the spiral galaxy M58 in Virgo on April 15, 1772. Johann Koehler discovered the elliptical galaxies M59 and M60 in Virgo on April 11, 1779. Caroline Herschel discovered C/1790 H1 (Herschel) on April 18, 1790. The first photograph of the Sun was taken on April 2, 1845. The first radar signal was bounced off of the Sun on April 7, 1959. The Hubble Space Telescope was placed in orbit on April 25, 1990. The Compton Gamma Ray Observatory achieved orbit on April 7, 1991.
The Lyrid meteor shower peaks on the night of April 22nd. Comet C/1861 G1 (Thatcher) is responsible for creating the Lyrid meteor shower. A typical zenithal hourly rate is about 20 meteors per hour but short outbursts have occurred occasionally. Fireballs are also possible. The radiant lies to the northwest of the first-magnitude star Vega, between the Keystone of Hercules and Lyra, at approximately right ascension 18h04m, declination 34 degrees north. A 67%-illuminated waning gibbous Moon will compromise the 2022 Lyrids, limiting the observed rate to perhaps 5 to 10 meteors per hour. For more on this year’s Lyrid meteor shower, browse earthsky.org/astronomy-essentials/everything-you-need-to-know-lyrid-meteor-shower and www.amsmeteors.org/meteor-showers/meteor-shower-calendar/
Information on passes of the ISS, the Tiangong, the USAF’s X-37B, the HST, Starlink, and other satellites can be found at www.heavens-above.com/
The Moon is 29.1 days old, is illuminated 0.2%, subtends 30.9', and is located in Cetus at 0:00 UT on April 1st. The Moon is at its greatest northern declination of +26.8 degrees on April 8th and its greatest southern declination of -26.9 degrees on April 22nd. Longitudinal libration is at a maximum of +4.9 degrees on April 1st and +5.5 degrees on April 28th and a minimum of -6.0 degrees on April 14th. Latitudinal libration is at a maximum of +6.8 degrees on April 25th and a minimum of -6.8 degrees on April 12th. Favorable librations occur for the following features: Crater Lyapunov on April 3rd, Mare Marginis on April 4th, Crater Shaler on April 17th, and Crater Gioja on April 21st. The Curtiss Cross occurs on April 24th and the Lunar X on April 8th. New Moon occurs on April 1st and April 30th. The Moon is at apogee on April 7th and at perigee on April 19th. The Moon passes close to the bright open cluster M45 (the Pleiades) in Taurus at 5:00 on April 5th, the first-magnitude star Aldebaran (Alpha Tauri) at 23:00 on April 5th, the bright open cluster M35 in Gemini at 21:00 on April 7th, the first-magnitude star Castor (Alpha Geminorum) at 10:00 on April 9th, the first-magnitude star Pollux (Beta Geminorum) at 16:00 on April 9th, the bright open cluster M44 (the Beehive Cluster) in Cancer at 20:00 on April 10th, the first-magnitude star Regulus (Alpha Leonis) at 15:00 on April 12th, the first-magnitude star Spica (Alpha Virginis) at 16:00 on April 16th, and the first-magnitude star Antares (Alpha Scorpii) at 20:00 on April 19th. The waxing crescent Moon forms an isosceles triangle with Castor and Pollux on the evening of April 8th. The waning crescent Moon lies midway between Venus and Mars at dawn on April 26th. The Moon, Venus, and Jupiter form a compact triangle on the morning of April 27th. The Moon occults Uranus on April 3rd and 1 Ceres on April 6th from certain parts of the world. Browse www.lunar-occultations.com/iota/iotandx.htm for information on lunar occultation events. Visit saberdoesthestars.wordpress.com/2011/07/05/saber-does-the-stars/ for tips on spotting extreme crescent Moons and curtrenz.com/moon.html for Full Moon and other lunar data. Go to skyandtelescope.org/wp-content/uploads/MoonMap.pdf and celestron-site-support-files.s3.us-east-1.amazonaws.com/support_files/Explore%20the%20Moon%20Map%2024%20x%2033%20RReeves-web.pdf and nightsky.jpl.nasa.gov/docs/ObserveMoon.pdf for simple lunar maps. Click on astrostrona.pl/moon-map/ for an excellent online lunar map. Visit www.ap-i.net/avl/en/start to download the free Virtual Moon Atlas. Consult time.unitarium.com/moon/where.html for current information on the Moon and www.fourmilab.ch/earthview/lunarform/lunarform.html for information on various lunar features. See svs.gsfc.nasa.gov/4955 a lunar phase and libration calculator and quickmap.lroc.asu.edu/?extent=-90,-25.2362636,90,25.2362636&proj=10&layers=NrBsFYBoAZIRnpEoAsjYIHYFcA2vIBvAXwF1SizSg for the Lunar Reconnaissance Orbiter Camera (LROC) Quickmap. Click on www.calendar-12.com/moon_calendar/2022/april for a lunar phase calendar for this month. Times and dates for the lunar crater light rays predicted to occur this month are available at www.lunar-occultations.com/rlo/rays/rays.htm
The Sun is located in Pisces on April 1st. It enters Aries on April 19th. A partial solar eclipse occurs on April 30th. Greatest eclipse occurs at 20:41 UT. This eclipse is the 66th of 71 in Saros series 119 and will be best viewed from Tierra del Fuego, Argentina and Puntas Arenas, Chile, where the Sun will be covered 52%. Further information on the eclipse can be found at eclipse.gsfc.nasa.gov/SEplot/SEplot2001/SE2022Apr30P.GIF and on page 50 of the April 2022 issue of Sky & Telescope.
Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on April 1: Mercury (-1.9 magnitude, 5.0", 100% illuminated, 1.35 a.u., Cetus), Venus (-4.4 magnitude, 21.7", 55% illuminated, 0.77 a.u., Capricornus), Mars (+1.1 magnitude, 5.2", 92% illuminated, 1.81 a.u., Capricornus), Jupiter (-2.0 magnitude, 33.4", 100% illuminated, 5.90 a.u., Aquarius), Saturn (+0.9 magnitude, 15.8", 100% illuminated, 10.52 a.u., Capricornus), Uranus (+5.9 magnitude, 3.4", 100% illuminated, 20.66 a.u. on April 16th, Aries), Neptune (+7.9 magnitude, 2.2", 100% illuminated, 30.77 a.u. on April 16th, Aquarius), and Pluto (+14.4 magnitude, 0.1", 100% illuminated, 34.77 a.u. on April 16th, Sagittarius).
Mercury and Uranus are located in the west in the evening. Venus, Mars, Jupiter, and Neptune are in the east and Saturn is in the southeast in the morning sky.
Venus, Mars, and Saturn all lie within Capricornus as the month begins. Jupiter (magnitude -2.1), Venus (magnitude -4.1), Mars (magnitude +1.0), and Saturn (magnitude +0.9) respectively form a line almost 32 degrees in length in the east-southeastern sky on the morning of April 18th.
Mercury undergoes its best evening apparition of the year for observers in the northern hemisphere this month. The fact that the ecliptic is highly inclined to the western horizon helps to position Mercury higher in the sky. The speediest planet is in superior conjunction on April 2nd, is at the ascending node on April 9th, is at perihelion on April 13th, is its greatest heliocentric latitude north on April 24th, and is at greatest eastern elongation on April 29th. Mercury passes two degrees north of Uranus on April 18th and 1.4 degrees south of M45 on April 29th. It fades in brightness from magnitude -1.9 to magnitude +0.3 over the course of the month.
Venus decreases somewhat in brightness and angular diameter but increases in illumination from 55% to 67% this month. The brightest planet enters Aquarius on April 4th and is at the descending node on April 10th. The waning crescent Moon passes four degrees south of Venus on April 27th. Venus passes just 0.007 degrees south of Neptune on April 27th. Venus (magnitude -4.1) and Jupiter (magnitude -2.1) are separated by just 28 arc minutes at an elongation from the Sun of about 43 degrees on the morning of April 30th. The two brightest planets are only 12 arc minutes apart around 19:00 UT (3:00 p.m. EDT) that afternoon. This will be the be closest conjunction of Venus and Jupiter at such a favorable elongation until November of 2039.
Mars (magnitude +1.1) and Saturn (magnitude +0.9) are separated by 0.3 degrees on April 4th. The Red Planet departs Capricornus and enters Aquarius on April 11th. The waning crescent Moon passes four degrees south of Mars on April 25th.
A waning crescent Moon passes four degrees south of Jupiter on the morning of April 27th. Venus passes a mere 0.2 degrees south of Jupiter on the last day of the month. At 6:30 a.m. EDT on that date, Callisto and Io lie to the west of Jupiter and Ganymede lies to the east. Data on Galilean satellite events is available at www.skyandtelescope.com/observing/interactive-sky-watching-tools/ and page 51 of the April 2022 issue of Sky & Telescope. For information on transits of Jupiter’s central meridian by the Great Red Spot, consult pages 50 and 51 of the April 2022 issue of Sky & Telescope.
As April begins, Saturn is positioned between Venus and Mars. By April 4th, the gap between Saturn and Mars shrinks to 0.3 degrees. The Ringed Planet passes north of a declination of -15 degrees for the first time since 2014 during the first week of April. Saturn is the westernmost planet in the lineup of Jupiter, Mars, Venus, and Saturn on the morning of April 18th. The waning crescent Moon passes five degrees south of Saturn on April 24th. Browse www.skyandtelescope.com/observing/interactive-sky-watching-tools/ for information on Saturn’s satellites.
Uranus is occulted by the waxing crescent Moon from certain parts of the world on April 3rd. Uranus lies just north of the sixth-magnitude B-type main sequence star Omicron Arietis as Mercury passes two degrees north of the ice giant on the evening of April 17th.
Eighth-magnitude Neptune is low in the east at dawn. Neptune has very close conjunctions with Jupiter on April 12th and Venus on April 27th. The waning crescent Moon passes four degrees south of Neptune on April 27th.
The dwarf planet Pluto is still not a viable target this month.
For more on the planets and how to locate them, browse www.nakedeyeplanets.com/
A summary on the planets for April can be found at earthsky.org/astronomy-essentials/visible-planets-tonight-mars-jupiter-venus-saturn-mercury/
The graphic at www.timeanddate.com/astronomy/planets/distance displays the apparent and comparative sizes of the planets, along with their magnitudes and distances, for a given date and time.
The rise and set times and locations of the planets can be determined by clicking on www.timeanddate.com/astronomy/night/
This month the dwarf planet/asteroid 1 Ceres shines at ninth magnitude as it progresses northeastward through Taurus. From April 11th to April 13th, the main belt asteroid lies about one degree north of the open cluster NGC 1746. Asteroid 8 Flora (magnitude +9.8) reaches opposition on April 12th, asteroid 15 Eunomia (magnitude +10.0) on April 16th, and asteroid 10 Hygiea (magnitude +9.3) on April 28th. An article on these three asteroids complete with finder charts can be found on pages 48 and 49 of the April 2022 issue of Sky & Telescope. Other asteroids brighter than magnitude +11.0 that reach opposition this month include 56 Europa (magnitude +10.8) on April 6th, asteroid 51 Nemausa (magnitude +10.2) on April 25th, and 88 Thisbe (magnitude +10.9) on April 28th. Click on www.asteroidoccultation.com/2022_04_si.htm for information on asteroid occultations taking place this month. See www.curtrenz.com/asteroids.html for additional current information on a number of asteroids.
Comet C/2021 O3 (PanSTARRS) travels northeastward from Cetus into Taurus during April. It lies west of Menkar (Alpha Ceti) on April 21st, east of Mercury on April 27th, and east of M45 on April 29th. This potentially bright comet reaches perihelion on April 21st and achieves peak brightness on April 23rd or April 24th. Comet C/2021 F1 (Lemmon-PanSTARRS) is at perihelion in Pisces on April 6th. Visit cometchasing.skyhound.com/ and www.aerith.net/comet/future-n.html and cobs.si/ for additional information on this and other comets visible this month.
A wealth of information on solar system celestial bodies is posted at www.curtrenz.com/astronomy.html and nineplanets.org/
Information on the celestial events transpiring each week can be found at astronomy.com/skythisweek and skyandtelescope.org/observing/sky-at-a-glance/
An informative video discussing astronomical objects worthy of observing each month can be found at hubblesite.org/resource-gallery/learning-resources/tonights-sky
Free star maps for this month can be downloaded at www.skymaps.com/downloads.html and whatsouttonight.com/
An online interactive star chart appears at skyandtelescope.org/interactive-sky-chart/
The fifth-magnitude G-type main-sequence star 61 Virginis - www.solstation.com/stars/61vir2co.jpg - is a sun-like star at a distance of 28 light years. It hosts three exoplanets and is visible to the naked-eye.
The pulsating Mira-type variable star R Canum Venaticorum (R CVn) attains a maximum brightness of magnitude +7.5 to +7.7 around the middle of the month.
The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from 2.1 to 3.4, on April 1st, 4th, 7th, 10th, 13th, 16th, 19th, 21st, 24th, 27th, and 30th. Consult www.skyandtelescope.com/observing/interactive-sky-watching-tools/ and page 50 of the April 2022 issue of Sky & Telescope for the times of the eclipses. For more on Algol, see stars.astro.illinois.edu/sow/Algol.html and www.solstation.com/stars2/algol3.htm
Data on current supernovae can be found at www.rochesterastronomy.org/snimages/
Information on observing some of the more prominent Messier galaxies is available at www.cloudynights.com/topic/358295-how-to-locate-some-of-the-major-messier-galaxies-and-helpful-advice-for-novice-amateur-astronomers/
Finder charts for the Messier objects and other deep-sky objects are posted at freestarcharts.com/messier and freestarcharts.com/ngc-ic and www.cambridge.org/turnleft/seasonal_skies_april-june
Telrad finder charts for the Messier Catalog and the SAC’s 110 Best of the NGC are posted at www.custerobservatory.org/docs/messier2.pdf and www.star-shine.ch/astro/messiercharts/messierTelrad.htm and www.saguaroastro.org/wp-content/sac-docs/Book110BestNGC.pdf
Steve Tonkin's The Binocular Sky Newsletter for April can be seen at binocularsky.com/newsletter/BinoSkyNL.pdf
Author Phil Harrington offers an excellent freeware planetarium program for binocular observers known as TUBA (Touring the Universe through Binoculars Atlas) at www.philharrington.net/tuba.htm
Stellarium and Cartes du Ciel are useful freeware planetarium programs that are available at stellarium.org/ and www.ap-i.net/skychart/en/start
Deep-sky object list generators can be found at www.virtualcolony.com/sac/ and telescopius.com/ and tonightssky.com/MainPage.php
Freeware sky atlases can be downloaded at www.deepskywatch.com/files/deepsky-atlas/Deep-Sky-Hunter-atlas-full.pdf and www.cloudynights.com/articles/cat/articles/observing-skills/free-mag-7-star-charts-r1021 and allans-stuff.com/triatlas/
Seventy-five binary and multiple stars for April: h4481 (Corvus); Aitken 1774, Gamma Crateris, Jacob 16, Struve 3072, h4456, Burnham 1078 (Crater); h4311, Burnham 219, N Hydrae, h4455, h4465 (Hydra); 31 Leonis, Alpha Leonis (Regulus), h2520, Struve 1417, 39 Leonis, Struve 1421, Gamma Leonis (Algieba), Otto Struve 216, 45 Leonis, Struve 1442, Struve 1447, 49 Leonis, Struve 1482, 54 Leonis, Struve 1506, Chi Leonis, 65 Leonis, Struve 1521, Struve 1527, Struve 1529, Iota Leonis, 81 Leonis, 83 Leonis, Tau Leonis, 88 Leonis, 90 Leonis, Struve 1565, Struve 1566, 93 Leonis, h1201, S Leonis (Leo); h2517, Struve 1405, Struve 1432, 33 Leo Minoris, Struve 1459, 40 Leo Minoris, Struve 1492 (Leo Minor); Struve 1401, Struve 1441, Struve 1456, Struve 1464, 35 Sextantis, 40 Sextantis, 41 Sextantis (Sextans); Struve 1402, Struve 1415, Struve 1427, Struve 1462, Struve 1486, Struve 1495, Struve 1510, Struve 1520, Xi Ursae Majoris, Nu Ursae Majoris, Struve 1541, 57 Ursae Majoris, Struve 1544, Struve 1553, Struve 1561, Struve 1563, 65 Ursae Majoris, Otto Struve 241 (Ursa Major)
Notable carbon star for April: V Hydrae (Hydra)
One hundred deep-sky objects for April: NGC 4024, NGC 4027 (Corvus); NGC 3511, NGC 3513, NGC 3672, NGC 3887, NGC 3892, NGC 3955, NGC 3962, NGC 3981 (Crater); NGC 3091, NGC 3109, NGC 3145, NGC 3203, NGC 3242, NGC 3309, NGC 3585, NGC 3621, NGC 3717, NGC 3904, NGC 3936 (Hydra); M65, M66, M95, M96, M105, NGC 3098, NGC 3162, NGC 3177, NGC 3185, NGC 3190, NGC 3226, NGC 3227, NGC 3300, NGC 3346, NGC 3367, NGC 3377, NGC 3384, NGC 3389, NGC 3412, NGC 3437, NGC 3489, NGC 3495, NGC 3507, NGC 3521, NGC 3593, NGC 3607, NGC 3608, NGC 3626, NGC 3628, NGC 3630, NGC 3640, NGC 3646, NGC 3655, NGC 3681, NGC 3684, NGC 3686, NGC 3691, NGC 3810, NGC 3842, NGC 3872, NGC 3900, NGC 4008 (Leo); NGC 3245, NGC 3254, NGC 3277, NGC 3294, NGC 3344, NGC 3414, NGC 3432, NGC 3486, NGC 3504 (Leo Minor); NGC 2990, NGC 3044, NGC 3055, NGC 3115, NGC 3156, NGC 3166, NGC 3169, NGC 3246, NGC 3423 (Sextans); IC 750, M97, M108, M109, NGC 3079, NGC 3184, NGC 3198, NGC 3310, NGC 3359, NGC 3610, NGC 3665, NGC 3675, NGC 3738, NGC 3877, NGC 3898, NGC 3941, NGC 3953, NGC 3998, NGC 4026 (Ursa Major)
Top ten deep-sky objects for April: M65, M66, M95, M96, M97, M105, M108, NGC 3115, NGC 3242, NGC 3628
Top ten binocular deep-sky objects for April: M65, M66, M95, M96, M97, M105, M108, M109, NGC 3115, NGC 3242
Challenge deep-sky object for April: Leo I (Leo)
The objects listed above are located between 10:00 and 12:00 hours of right ascension.
All times, unless otherwise noted, are UT (subtract four hours and, when appropriate, one calendar day for EDT)
4/1 New Moon (lunation 1228) occurs at 6:24
4/2 Mercury is in superior conjunction at 23:00
4/3 The Moon is 0.6 degrees south of Uranus, with an occultation taking place in a portion of western central Africa, St. Helena, Ascension Island, and southern and eastern South America, at 17:00
4/4 Mars is 0.3 degrees south of Saturn at 22:00
4/6 The Moon is 0.2 degrees south of the dwarf planet/asteroid 1 Ceres, with an occultation taking place in most of Micronesia, Papua New Guinea, southeastern China, most of southeastern Asia, southern and eastern India, parts of eastern Africa, and Madagascar, at 9:00
4/7 The Moon is at apogee, subtending 29' 33'' from a distance of 404,436 kilometers (251,306 miles), at 19:11
4/8 The Lunar X (the Purbach or Werner Cross), an X-shaped illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to be visible at 20:20
4/9 Mercury is at the ascending node today; First Quarter Moon occurs at 6:48
4/10 Venus is at the descending node today
4/12 Asteroid 2 Pallas is in conjunction with the Sun at 3:00; Jupiter is 0.1 degrees north of Neptune at 20:00
4/13 Mercury is at perihelion today
4/16 Full Moon, known as the Egg, Grass, or Pink Moon, occurs at 18:55
4/18 Mercury is 2 degrees north of Uranus at 13:00
4/19 The Moon is at perigee, subtending 32' 44'' from a distance of 365,145 kilometers (226,890 miles), at 15:13
4/22 The peak of the Lyrid meteor shower (15 to 20 meteors per hour) is predicted to occur at 18:00
4/23 Last Quarter Moon occurs at 11:56
4/24 Mercury is at its greatest heliocentric latitude north today; the Moon is 5 degrees south of Saturn at 21:00; the Curtiss Cross, an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart, is predicted to be visible at 22:11
4/25 The Moon is 4 degrees south of Mars at 22:00
4/27 The Moon is 4 degrees south of Venus at 2:00; the Moon is 4 degrees south of Jupiter at 8:00; the Moon, Venus, and Jupiter lie within a circle with a diameter of 4.1 degrees at 9:00; Venus is 0.007 degrees south of Neptune at 19:00
4/29 Mercury is at greatest eastern elongation (20.6 degrees) at 8:00; Mercury is 1.4 degrees south of the bright open cluster M45 (the Pleiades or Subaru) in Taurus at 19:00
4/30 A partial solar eclipse visible from far northern Antarctica, southern South America, and the southern portions of the Pacific and Atlantic Oceans begins at 18:45 and ends at 22:38; Venus is 0.2 degrees south of Jupiter at 19:00; New Moon (lunation 1229) occurs at 20:29
Charles Messier discovered the open cluster M50 in Monoceros on April 5, 1772. Charles Messier discovered the spiral galaxy M58 in Virgo on April 15, 1772. Johann Koehler discovered the elliptical galaxies M59 and M60 in Virgo on April 11, 1779. Caroline Herschel discovered C/1790 H1 (Herschel) on April 18, 1790. The first photograph of the Sun was taken on April 2, 1845. The first radar signal was bounced off of the Sun on April 7, 1959. The Hubble Space Telescope was placed in orbit on April 25, 1990. The Compton Gamma Ray Observatory achieved orbit on April 7, 1991.
The Lyrid meteor shower peaks on the night of April 22nd. Comet C/1861 G1 (Thatcher) is responsible for creating the Lyrid meteor shower. A typical zenithal hourly rate is about 20 meteors per hour but short outbursts have occurred occasionally. Fireballs are also possible. The radiant lies to the northwest of the first-magnitude star Vega, between the Keystone of Hercules and Lyra, at approximately right ascension 18h04m, declination 34 degrees north. A 67%-illuminated waning gibbous Moon will compromise the 2022 Lyrids, limiting the observed rate to perhaps 5 to 10 meteors per hour. For more on this year’s Lyrid meteor shower, browse earthsky.org/astronomy-essentials/everything-you-need-to-know-lyrid-meteor-shower and www.amsmeteors.org/meteor-showers/meteor-shower-calendar/
Information on passes of the ISS, the Tiangong, the USAF’s X-37B, the HST, Starlink, and other satellites can be found at www.heavens-above.com/
The Moon is 29.1 days old, is illuminated 0.2%, subtends 30.9', and is located in Cetus at 0:00 UT on April 1st. The Moon is at its greatest northern declination of +26.8 degrees on April 8th and its greatest southern declination of -26.9 degrees on April 22nd. Longitudinal libration is at a maximum of +4.9 degrees on April 1st and +5.5 degrees on April 28th and a minimum of -6.0 degrees on April 14th. Latitudinal libration is at a maximum of +6.8 degrees on April 25th and a minimum of -6.8 degrees on April 12th. Favorable librations occur for the following features: Crater Lyapunov on April 3rd, Mare Marginis on April 4th, Crater Shaler on April 17th, and Crater Gioja on April 21st. The Curtiss Cross occurs on April 24th and the Lunar X on April 8th. New Moon occurs on April 1st and April 30th. The Moon is at apogee on April 7th and at perigee on April 19th. The Moon passes close to the bright open cluster M45 (the Pleiades) in Taurus at 5:00 on April 5th, the first-magnitude star Aldebaran (Alpha Tauri) at 23:00 on April 5th, the bright open cluster M35 in Gemini at 21:00 on April 7th, the first-magnitude star Castor (Alpha Geminorum) at 10:00 on April 9th, the first-magnitude star Pollux (Beta Geminorum) at 16:00 on April 9th, the bright open cluster M44 (the Beehive Cluster) in Cancer at 20:00 on April 10th, the first-magnitude star Regulus (Alpha Leonis) at 15:00 on April 12th, the first-magnitude star Spica (Alpha Virginis) at 16:00 on April 16th, and the first-magnitude star Antares (Alpha Scorpii) at 20:00 on April 19th. The waxing crescent Moon forms an isosceles triangle with Castor and Pollux on the evening of April 8th. The waning crescent Moon lies midway between Venus and Mars at dawn on April 26th. The Moon, Venus, and Jupiter form a compact triangle on the morning of April 27th. The Moon occults Uranus on April 3rd and 1 Ceres on April 6th from certain parts of the world. Browse www.lunar-occultations.com/iota/iotandx.htm for information on lunar occultation events. Visit saberdoesthestars.wordpress.com/2011/07/05/saber-does-the-stars/ for tips on spotting extreme crescent Moons and curtrenz.com/moon.html for Full Moon and other lunar data. Go to skyandtelescope.org/wp-content/uploads/MoonMap.pdf and celestron-site-support-files.s3.us-east-1.amazonaws.com/support_files/Explore%20the%20Moon%20Map%2024%20x%2033%20RReeves-web.pdf and nightsky.jpl.nasa.gov/docs/ObserveMoon.pdf for simple lunar maps. Click on astrostrona.pl/moon-map/ for an excellent online lunar map. Visit www.ap-i.net/avl/en/start to download the free Virtual Moon Atlas. Consult time.unitarium.com/moon/where.html for current information on the Moon and www.fourmilab.ch/earthview/lunarform/lunarform.html for information on various lunar features. See svs.gsfc.nasa.gov/4955 a lunar phase and libration calculator and quickmap.lroc.asu.edu/?extent=-90,-25.2362636,90,25.2362636&proj=10&layers=NrBsFYBoAZIRnpEoAsjYIHYFcA2vIBvAXwF1SizSg for the Lunar Reconnaissance Orbiter Camera (LROC) Quickmap. Click on www.calendar-12.com/moon_calendar/2022/april for a lunar phase calendar for this month. Times and dates for the lunar crater light rays predicted to occur this month are available at www.lunar-occultations.com/rlo/rays/rays.htm
The Sun is located in Pisces on April 1st. It enters Aries on April 19th. A partial solar eclipse occurs on April 30th. Greatest eclipse occurs at 20:41 UT. This eclipse is the 66th of 71 in Saros series 119 and will be best viewed from Tierra del Fuego, Argentina and Puntas Arenas, Chile, where the Sun will be covered 52%. Further information on the eclipse can be found at eclipse.gsfc.nasa.gov/SEplot/SEplot2001/SE2022Apr30P.GIF and on page 50 of the April 2022 issue of Sky & Telescope.
Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on April 1: Mercury (-1.9 magnitude, 5.0", 100% illuminated, 1.35 a.u., Cetus), Venus (-4.4 magnitude, 21.7", 55% illuminated, 0.77 a.u., Capricornus), Mars (+1.1 magnitude, 5.2", 92% illuminated, 1.81 a.u., Capricornus), Jupiter (-2.0 magnitude, 33.4", 100% illuminated, 5.90 a.u., Aquarius), Saturn (+0.9 magnitude, 15.8", 100% illuminated, 10.52 a.u., Capricornus), Uranus (+5.9 magnitude, 3.4", 100% illuminated, 20.66 a.u. on April 16th, Aries), Neptune (+7.9 magnitude, 2.2", 100% illuminated, 30.77 a.u. on April 16th, Aquarius), and Pluto (+14.4 magnitude, 0.1", 100% illuminated, 34.77 a.u. on April 16th, Sagittarius).
Mercury and Uranus are located in the west in the evening. Venus, Mars, Jupiter, and Neptune are in the east and Saturn is in the southeast in the morning sky.
Venus, Mars, and Saturn all lie within Capricornus as the month begins. Jupiter (magnitude -2.1), Venus (magnitude -4.1), Mars (magnitude +1.0), and Saturn (magnitude +0.9) respectively form a line almost 32 degrees in length in the east-southeastern sky on the morning of April 18th.
Mercury undergoes its best evening apparition of the year for observers in the northern hemisphere this month. The fact that the ecliptic is highly inclined to the western horizon helps to position Mercury higher in the sky. The speediest planet is in superior conjunction on April 2nd, is at the ascending node on April 9th, is at perihelion on April 13th, is its greatest heliocentric latitude north on April 24th, and is at greatest eastern elongation on April 29th. Mercury passes two degrees north of Uranus on April 18th and 1.4 degrees south of M45 on April 29th. It fades in brightness from magnitude -1.9 to magnitude +0.3 over the course of the month.
Venus decreases somewhat in brightness and angular diameter but increases in illumination from 55% to 67% this month. The brightest planet enters Aquarius on April 4th and is at the descending node on April 10th. The waning crescent Moon passes four degrees south of Venus on April 27th. Venus passes just 0.007 degrees south of Neptune on April 27th. Venus (magnitude -4.1) and Jupiter (magnitude -2.1) are separated by just 28 arc minutes at an elongation from the Sun of about 43 degrees on the morning of April 30th. The two brightest planets are only 12 arc minutes apart around 19:00 UT (3:00 p.m. EDT) that afternoon. This will be the be closest conjunction of Venus and Jupiter at such a favorable elongation until November of 2039.
Mars (magnitude +1.1) and Saturn (magnitude +0.9) are separated by 0.3 degrees on April 4th. The Red Planet departs Capricornus and enters Aquarius on April 11th. The waning crescent Moon passes four degrees south of Mars on April 25th.
A waning crescent Moon passes four degrees south of Jupiter on the morning of April 27th. Venus passes a mere 0.2 degrees south of Jupiter on the last day of the month. At 6:30 a.m. EDT on that date, Callisto and Io lie to the west of Jupiter and Ganymede lies to the east. Data on Galilean satellite events is available at www.skyandtelescope.com/observing/interactive-sky-watching-tools/ and page 51 of the April 2022 issue of Sky & Telescope. For information on transits of Jupiter’s central meridian by the Great Red Spot, consult pages 50 and 51 of the April 2022 issue of Sky & Telescope.
As April begins, Saturn is positioned between Venus and Mars. By April 4th, the gap between Saturn and Mars shrinks to 0.3 degrees. The Ringed Planet passes north of a declination of -15 degrees for the first time since 2014 during the first week of April. Saturn is the westernmost planet in the lineup of Jupiter, Mars, Venus, and Saturn on the morning of April 18th. The waning crescent Moon passes five degrees south of Saturn on April 24th. Browse www.skyandtelescope.com/observing/interactive-sky-watching-tools/ for information on Saturn’s satellites.
Uranus is occulted by the waxing crescent Moon from certain parts of the world on April 3rd. Uranus lies just north of the sixth-magnitude B-type main sequence star Omicron Arietis as Mercury passes two degrees north of the ice giant on the evening of April 17th.
Eighth-magnitude Neptune is low in the east at dawn. Neptune has very close conjunctions with Jupiter on April 12th and Venus on April 27th. The waning crescent Moon passes four degrees south of Neptune on April 27th.
The dwarf planet Pluto is still not a viable target this month.
For more on the planets and how to locate them, browse www.nakedeyeplanets.com/
A summary on the planets for April can be found at earthsky.org/astronomy-essentials/visible-planets-tonight-mars-jupiter-venus-saturn-mercury/
The graphic at www.timeanddate.com/astronomy/planets/distance displays the apparent and comparative sizes of the planets, along with their magnitudes and distances, for a given date and time.
The rise and set times and locations of the planets can be determined by clicking on www.timeanddate.com/astronomy/night/
This month the dwarf planet/asteroid 1 Ceres shines at ninth magnitude as it progresses northeastward through Taurus. From April 11th to April 13th, the main belt asteroid lies about one degree north of the open cluster NGC 1746. Asteroid 8 Flora (magnitude +9.8) reaches opposition on April 12th, asteroid 15 Eunomia (magnitude +10.0) on April 16th, and asteroid 10 Hygiea (magnitude +9.3) on April 28th. An article on these three asteroids complete with finder charts can be found on pages 48 and 49 of the April 2022 issue of Sky & Telescope. Other asteroids brighter than magnitude +11.0 that reach opposition this month include 56 Europa (magnitude +10.8) on April 6th, asteroid 51 Nemausa (magnitude +10.2) on April 25th, and 88 Thisbe (magnitude +10.9) on April 28th. Click on www.asteroidoccultation.com/2022_04_si.htm for information on asteroid occultations taking place this month. See www.curtrenz.com/asteroids.html for additional current information on a number of asteroids.
Comet C/2021 O3 (PanSTARRS) travels northeastward from Cetus into Taurus during April. It lies west of Menkar (Alpha Ceti) on April 21st, east of Mercury on April 27th, and east of M45 on April 29th. This potentially bright comet reaches perihelion on April 21st and achieves peak brightness on April 23rd or April 24th. Comet C/2021 F1 (Lemmon-PanSTARRS) is at perihelion in Pisces on April 6th. Visit cometchasing.skyhound.com/ and www.aerith.net/comet/future-n.html and cobs.si/ for additional information on this and other comets visible this month.
A wealth of information on solar system celestial bodies is posted at www.curtrenz.com/astronomy.html and nineplanets.org/
Information on the celestial events transpiring each week can be found at astronomy.com/skythisweek and skyandtelescope.org/observing/sky-at-a-glance/
An informative video discussing astronomical objects worthy of observing each month can be found at hubblesite.org/resource-gallery/learning-resources/tonights-sky
Free star maps for this month can be downloaded at www.skymaps.com/downloads.html and whatsouttonight.com/
An online interactive star chart appears at skyandtelescope.org/interactive-sky-chart/
The fifth-magnitude G-type main-sequence star 61 Virginis - www.solstation.com/stars/61vir2co.jpg - is a sun-like star at a distance of 28 light years. It hosts three exoplanets and is visible to the naked-eye.
The pulsating Mira-type variable star R Canum Venaticorum (R CVn) attains a maximum brightness of magnitude +7.5 to +7.7 around the middle of the month.
The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from 2.1 to 3.4, on April 1st, 4th, 7th, 10th, 13th, 16th, 19th, 21st, 24th, 27th, and 30th. Consult www.skyandtelescope.com/observing/interactive-sky-watching-tools/ and page 50 of the April 2022 issue of Sky & Telescope for the times of the eclipses. For more on Algol, see stars.astro.illinois.edu/sow/Algol.html and www.solstation.com/stars2/algol3.htm
Data on current supernovae can be found at www.rochesterastronomy.org/snimages/
Information on observing some of the more prominent Messier galaxies is available at www.cloudynights.com/topic/358295-how-to-locate-some-of-the-major-messier-galaxies-and-helpful-advice-for-novice-amateur-astronomers/
Finder charts for the Messier objects and other deep-sky objects are posted at freestarcharts.com/messier and freestarcharts.com/ngc-ic and www.cambridge.org/turnleft/seasonal_skies_april-june
Telrad finder charts for the Messier Catalog and the SAC’s 110 Best of the NGC are posted at www.custerobservatory.org/docs/messier2.pdf and www.star-shine.ch/astro/messiercharts/messierTelrad.htm and www.saguaroastro.org/wp-content/sac-docs/Book110BestNGC.pdf
Steve Tonkin's The Binocular Sky Newsletter for April can be seen at binocularsky.com/newsletter/BinoSkyNL.pdf
Author Phil Harrington offers an excellent freeware planetarium program for binocular observers known as TUBA (Touring the Universe through Binoculars Atlas) at www.philharrington.net/tuba.htm
Stellarium and Cartes du Ciel are useful freeware planetarium programs that are available at stellarium.org/ and www.ap-i.net/skychart/en/start
Deep-sky object list generators can be found at www.virtualcolony.com/sac/ and telescopius.com/ and tonightssky.com/MainPage.php
Freeware sky atlases can be downloaded at www.deepskywatch.com/files/deepsky-atlas/Deep-Sky-Hunter-atlas-full.pdf and www.cloudynights.com/articles/cat/articles/observing-skills/free-mag-7-star-charts-r1021 and allans-stuff.com/triatlas/
Seventy-five binary and multiple stars for April: h4481 (Corvus); Aitken 1774, Gamma Crateris, Jacob 16, Struve 3072, h4456, Burnham 1078 (Crater); h4311, Burnham 219, N Hydrae, h4455, h4465 (Hydra); 31 Leonis, Alpha Leonis (Regulus), h2520, Struve 1417, 39 Leonis, Struve 1421, Gamma Leonis (Algieba), Otto Struve 216, 45 Leonis, Struve 1442, Struve 1447, 49 Leonis, Struve 1482, 54 Leonis, Struve 1506, Chi Leonis, 65 Leonis, Struve 1521, Struve 1527, Struve 1529, Iota Leonis, 81 Leonis, 83 Leonis, Tau Leonis, 88 Leonis, 90 Leonis, Struve 1565, Struve 1566, 93 Leonis, h1201, S Leonis (Leo); h2517, Struve 1405, Struve 1432, 33 Leo Minoris, Struve 1459, 40 Leo Minoris, Struve 1492 (Leo Minor); Struve 1401, Struve 1441, Struve 1456, Struve 1464, 35 Sextantis, 40 Sextantis, 41 Sextantis (Sextans); Struve 1402, Struve 1415, Struve 1427, Struve 1462, Struve 1486, Struve 1495, Struve 1510, Struve 1520, Xi Ursae Majoris, Nu Ursae Majoris, Struve 1541, 57 Ursae Majoris, Struve 1544, Struve 1553, Struve 1561, Struve 1563, 65 Ursae Majoris, Otto Struve 241 (Ursa Major)
Notable carbon star for April: V Hydrae (Hydra)
One hundred deep-sky objects for April: NGC 4024, NGC 4027 (Corvus); NGC 3511, NGC 3513, NGC 3672, NGC 3887, NGC 3892, NGC 3955, NGC 3962, NGC 3981 (Crater); NGC 3091, NGC 3109, NGC 3145, NGC 3203, NGC 3242, NGC 3309, NGC 3585, NGC 3621, NGC 3717, NGC 3904, NGC 3936 (Hydra); M65, M66, M95, M96, M105, NGC 3098, NGC 3162, NGC 3177, NGC 3185, NGC 3190, NGC 3226, NGC 3227, NGC 3300, NGC 3346, NGC 3367, NGC 3377, NGC 3384, NGC 3389, NGC 3412, NGC 3437, NGC 3489, NGC 3495, NGC 3507, NGC 3521, NGC 3593, NGC 3607, NGC 3608, NGC 3626, NGC 3628, NGC 3630, NGC 3640, NGC 3646, NGC 3655, NGC 3681, NGC 3684, NGC 3686, NGC 3691, NGC 3810, NGC 3842, NGC 3872, NGC 3900, NGC 4008 (Leo); NGC 3245, NGC 3254, NGC 3277, NGC 3294, NGC 3344, NGC 3414, NGC 3432, NGC 3486, NGC 3504 (Leo Minor); NGC 2990, NGC 3044, NGC 3055, NGC 3115, NGC 3156, NGC 3166, NGC 3169, NGC 3246, NGC 3423 (Sextans); IC 750, M97, M108, M109, NGC 3079, NGC 3184, NGC 3198, NGC 3310, NGC 3359, NGC 3610, NGC 3665, NGC 3675, NGC 3738, NGC 3877, NGC 3898, NGC 3941, NGC 3953, NGC 3998, NGC 4026 (Ursa Major)
Top ten deep-sky objects for April: M65, M66, M95, M96, M97, M105, M108, NGC 3115, NGC 3242, NGC 3628
Top ten binocular deep-sky objects for April: M65, M66, M95, M96, M97, M105, M108, M109, NGC 3115, NGC 3242
Challenge deep-sky object for April: Leo I (Leo)
The objects listed above are located between 10:00 and 12:00 hours of right ascension.