Skylights: February 2024

The Sun begins to set after 5:00pm EST on the 1st. After spending the past 27 days in Capricornus, the Sun enters Aquarius on the 16th.

After passing just 0.7° northeast of Spica, in Virgo, on the morning of the 1st, last quarter Moon occurs in Libra, at 6:18pm on the 2nd.

Through its waning crescent phase, the Moon is 4.9° east of Antares, in Scorpius, on the 5th, and on the 7th, the 28-day Moon is 7.5° south-southwest of Venus, and 12° southwest of Mars–almost directly to its right over the horizon.

The Moon is new on the 9th, at 5:59pm EST, marking the start of Lunation 1251.

February, March and April mark the time of the year when observing the very “young” waxing crescent Moon is most favorable in mid-northern latitudes. This is due to the apparent steep angle of the ecliptic away from the horizon following sunset, making the Moon’s position on each successive night close to vertically above the previous night’s position.

Such an opportunity to spot a young Moon occurs on the 10th, when about 45 minutes after sunset the 24-hour old crescent can be spotted a respectable 4.5° above the west-southwest horizon. Using binoculars or a rich field telescope is the best way to observe the 1.4% illuminated crescent. Don’t miss the opportunity to photograph it as well. As the minutes pass and the sky darkens, try to see the Earthshine illuminating the entire globe of the Moon, and in that night’s case, also spot Saturn just 3° to its one-o’clock position. This may be your last opportunity to see Saturn until it returns to the morning sky later next month.

If you don’t have a low enough horizon, or you otherwise miss seeing the 1-day-young Moon on the 10th, the 5.7% illuminated crescent on the 11th is much easier to see, and just as beautiful, especially as its Earthshine will be more pronounced as it sets into a darker horizon. The Moon on this night visits another planet, as just 5.2° above it will be distant Neptune, its magnitude 7.8 glow significantly diminished by the thicker layers of atmosphere near the horizon, so even a small, wide field telescope may not capture both objects in the same field of view.

The Moon joins Jupiter on the 14th, with the two objects separated by 3.1° before Moonset, making the bright pair easily visible in one telescopic field of view. It is worth the effort to observe this, as you will see not just two, but six solar system bodies in one view, with Jupiter’s four Galilean moons visible in a tight arrangement around the giant planet. To the east, or above Jupiter, are Callisto and Io, and just below Jupiter, arranged nearly perpendicular to the other pair, are Europa and Ganymede (south-to-north).

The following night, on the 15th, the 6-day crescent Moon appears 2.5° north of Uranus, presenting a good opportunity to spy the seventh planet. They are closest at around 8:30pm EST, and at this time you can use the Moon’s terminator as a guideline, pointing to the magnitude 5.7 planet.

The first quarter Moon, in Taurus, is at 10:01am on the 16th. In the early evening, don’t miss the Pleiades cluster just 1.0° from the Moon, which will be an exceptional sight in binoculars and small telescopes. Consider this the opening act to several more close conjunctions of the Moon and the Pleiades, including some occultations, later this year.

Through its waxing gibbous phase, the Moon passes 1.6° south of Pollux, in Gemini, on the 20th, 2.5° north of the Beehive Cluster, M44, in Cancer, on the 22nd, and 2.8° north-northeast of Regulus, in Leo, on the 23rd.

The Full Snow Moon occurs at 7:30am EST on February 24th in Leo, just a few degrees from  Regulus. The Moon rises at 4:40pm on the 23rd, and sets at 6:49am on the 24th. 

During waning gibbous, the Moon passes 2.6° northwest of Spica, in Virgo, on the 28th.

The Moon occults three moderately bright stars in February. Lunar occultations of stars are among the sky’s more dramatic events to observe, and they’re easily visible with any small telescope with a modest amount of magnification.  

On the 13th, zeta Piscium, a double star on the Astronomical League’s Double Star Observing Program with magnitude 5.2 and 6.3 components separated by 22.8 arcseconds, is occulted by the dark limb of the crescent Moon. Zeta Psc A is occulted at 6:27pm, and the B component disappears about a minute later. At 7:00pm, the brighter star reemerges near the southern cusp, followed by the B star about three quarters of a minute later.

36 Tauri, a 5.5 magnitude star, is occulted by the dark limb of the waxing gibbous Moon on the 16th. Ingress occurs at 11:10pm. The star reappears 48 minutes later on the southeastern limb..

Zavijava, a magnitude 3.6 star in Virgo, is occulted by the waning gibbous Moon on the morning of the 26th. The star disappears behind the bright limb of the Moon at 4:37am, and reappears from the dark limb at 5:29am.

February is not a good month for observing Mercury, as the innermost planet rises just under an hour before the Sun early in the month, and remains low in the sky as it appears closer to the Sun each morning on its way to superior conjunction on the 28th. Mercury undergoes its best evening apparition next month.

An opportunity to see Mercury and the Moon, albeit a challenging one, presents itself on the 10th. Find a location with an exceptionally clear southeastern horizon, and wait for the 28-day crescent Moon to rise at 6:22am. The Moon, with its sunlit limb pointed almost directly horizontal, is 7° to the right, and just one Moon diameter below Mercury. Additionally, Mars is 5.3° directly above the Moon.

Venus is in Sagittarius during the first half of February, moving into Capricornus on the 16th. By the end of February, Venus will be rising less than one hour before sunrise.

Venus is 0.6° north of Mars on the 22nd. As both planets are on the opposite side of the Sun as Earth, this conjunction demonstrates how the different orbital velocities affect the apparent motions of planets in different realms of the solar system. Venus, being an inferior planet – that is, a planet whose orbit is inside that of Earth’s – travels along its orbit faster than Earth. Its apparent position in our sky is therefore appearing to get closer to the Sun, while Mars, being a superior planet – one that orbits outside of Earth’s orbit – is moving slower, and appears to be moving away from the Sun. Venus will soon undergo its conjunction, while Mars is on its way to opposition in eleven months.

While most of the planets are low on the horizon after sunset or before sunrise this month, Jupiter is the only bright planet visible during the full darkness of night. Located high in the southwest, in Aries, during February evenings, there is still much time to observe the planet and its four bright moons.

On the 2nd, all four Galilean satellites appear in order of orbital radius to the east of Jupiter, starting at 7:10pm.

On the 5th, a close arrangement of all moons except Ganymede appears close to Jupiter, and Callisto moves below Jupiter’s south pole at 8:30pm.

An apparent perpendicular orientation of Callisto and Ganymede with respect to Io and Europa occurs at 7:00pm on the 12th.

Another instance of the moons appearing in order of orbital radius occurs, this time on the west side of Jupiter, on the 26th.

Jupiter departs the sky around midnight at the beginning of the month, and meets the west-northwestern horizon by 10:30pm EST by month’s end.

Saturn

One last chance, albeit a challenging one, to see Saturn in the evening sky occurs on the 10th, when the 1-day crescent Moon is just 3.1° to its south-southeast, almost directly below the planet, right after sunset.

After being in our evening sky for the past eight months, Saturn reaches conjunction–passing behind the Sun from our view–on the 28th. It is notable that both Saturn and Mercury are at superior conjunction on the same day, just 13 hours apart. 

The ringed planet becomes visible again in the morning sky in April.

Besides Jupiter, Uranus is the only other planet in a favorable position for observation high in the sky in February. The seventh planet reaches eastern quadrature on the 8th. Quadrature is the point at which a planet is elongated 90° from the Sun on the heliocentric coordinate system, is positioned roughly on the meridian at sunset, and sets around midnight.

Like Jupiter, Uranus also resides in Aries, and its position high in the sky through the evening hours allows plenty of time for telescoping observation. Though it is gradually moving eastward, you can still use Botein (delta Arietis) to locate it, as it remains within 3° to the south-southwest of the 4.4 magnitude star.

The 6-day crescent Moon is 2.5° north of Uranus on the 15th.

Neptune, in Pisces, follows Saturn into the western horizon during the early evening hours of February. By the end of the month, it sets before the end of astronomical twilight. On the 10th, the 2-day crescent Moon is 5.4° below the outermost planet.

Ceres is moving eastward through Sagittarius. At over 3 AU, its magnitude 9.0 speck will be a challenge to discern as it moves through the densest region of the Milky Way, but on the 10th and 11th, it passes through the apparent gap separating the Lagoon and Trifid Nebulae, Messiers 8 and 20, respectively.

Distant Pluto, now in Capricornus, does not rise before the onset of astronomical twilight in February, and will be difficult to observe.

Asteroid 4 Vesta ends its retrograde loop in Taurus, and as such, it remains relatively stationary, moving slightly northward, but still about 3.5° northwest of Tianguan (zeta Tauri), and in the same field of view as the Crab Nebula in a small telescope.

As our distance from Vesta increases to greater than 2 AU, it dims from magnitude 7.3 to 7.6, placing it within reach of binoculars on dark, moonless nights in February.

3 Juno, which reaches opposition early next month, brightens to magnitude 8.6 in Leo. At the beginning of the month, it can be found by drawing a line from Zosma (delta Leonis) through Chertan (theta Leonis) straight south by 16°. While searching for it with your telescope, you may notice that it is about 2.5° east of the galaxy NGC 3521. From there, it moves northwestward, in the direction of Regulus.

While there are many comets visible in the sky at any given time, there are two that are noteworthy due to their brightness and positions in February.

The first, visible in the western sky after sunset, is 12P/Pons-Brooks. During the month of February, it moves eastward from Cygnus, through southern Lacerta, and into western Andromeda. Its apparent motion to the east keeps it in an approximately steady position 20-25° above the western horizon during the next several weeks, and it is expected to brighten to 8th magnitude by the end of the month.

Second, 62P/Tsuchinshan 1 is closest to Earth, at 0.50 AU, on the 1st. It is moving slightly eastward in Virgo, about 6° west of Vindemiatrix (epsilon Virginis), although its 8th magnitude may be easily mistaken for one of the Realm of the Galaxies, which lies just a few degrees to its north.

February’s mid-winter nights bring us shortening darkness, but still early enough to spend several hours exploring the universe before midnight.

For early evening observers, our favorite winter constellations are now available high in the sky. The Winter Milky Way is at its best, though you’ll want to find a very dark site, and observe during the first half of the month, when bright moonlight doesn’t interfere.

The great bear Ursa Major stands on his tail in the northeast, as the Big Dipper’s pointer stars assume their eastern extension from Polaris.

The constellations of autumn, including Cassiopeia and Andromeda, are on the decline in the western sky, and in the eastern sky, some of the constellations of spring are on the rise. A little later in the evening, Arcturus, the 4th brightest star in the sky, and the star often associated with the coming of spring, rises in the east.