The Night Sky This Month: February 2018

Constellations that are prominent in the northern sky (other than the circumpolar constellations) at this time include Cancer, Leo, Hydra, and rather surprisingly, the little, and rather faint constellation Sextans (the Sextant), squeezed in between the large constellation Hydra below it, and the constellation Leo, above it.


The month of February offers great opportunities to observe the phenomenon of “earthshine”, which is when sunlight reflected off the Earth illuminates a portion of the Moon’s surface. Earthshine will occur from the 8th until the 14th of the month, and again from the 16th to the 22nd, and while it is a naked-eye phenomenon, observing the Moon with binoculars or small telescopes at these times offers views of familiar lunar objects that may be difficult or impossible to replicate under other lighting conditions.


Note that since the lunar cycle is longer than the number of days in February, there is no full moon this month. When this happens (about four times per century), January and March usually have two Blue (Full) Moons, as is the case in 2018.

Full Moon: 1st
Last Quarter: 7th
New Moon: 15th
First Quarter: 23rd


Mercury will reach a position of superior conjunction with the Sun on the 17th, after which date it will start to set progressively earlier until by month’s end it will set about 60 minutes or so after the Sun. Note that although the little planet may be visible in the time between sunset and its own setting, it will be very low above the south-western horizon, and may therefore be lost in atmospheric haze and murk.

Venus becomes an early evening object during the first days of February, but month’s end, it will set only about an hour or so after the Sun, which means that while looking for Mercury, you might stumble across Venus as well. Note that since Venus will be the brighter of the two planets, it might be easier to located Mercury by finding Venus first. The two planets will also form a reasonably close pairing on the 28th, when Venus will be about 2.5 degrees to the upper right of Mercury. Look for the pairing about 4 degrees above the west-south-western horizon at about 06H:00 PM.

Mars is now a predawn object, rising as it does about 4 hours before the Sun. The red planet continues to move eastwards through Scorpius and into Ophiuchus. The planet will brighten considerably throughout the month, although it remains fairly low over the south-eastern horizon from about 04H:00 AM. By month’s end, however, Mars will be as bright as the stars Altair in the constellation Aquila and Aldebaran in Taurus. Mars will also form a close pairing with the waning crescent Moon on the 9th, when it will be about 3 degrees to the lower right of the Moon just after the planer rises.

Jupiter rises at about 02H:00 AM as the month begins, but then progressively earlier until the end of February when it will rise about 30 minutes or so after midnight. Apart from the Moon, Jupiter will be the brightest object in the predawn sky, so it will be hard to miss the King of the planets as it moves eastwards through the constellation Libra. On the mornings of the 7th and the 8th, the last quarter moon will be passing just above Jupiter, so look for this close pairing, and of course the Galilean moons, on these dates.

Saturn is now in the constellation Sagittarius, and although reasonably good telescopic views of the ringed planet may be had provided seeing conditions allow, the planet will remain low on the south-eastern horizon. On the morning of the 11th, at about 06H:00, the waning crescent Moon will be located about 4 degrees to the upper right of Saturn, so be sure to look for this pretty pairing.

Uranus is still in the constellation Pisces, and although it sets in the late evening, it is at the very edge of naked eye visibility at magnitude +5.85, so use at least binoculars to get the best views. Look for Uranus about 3 degrees westward of the star Omicron Piscium (Torcularis Septentri), which will be shining at magnitude 4.26.

Neptune is not visible during February, since it is below naked-eye visibility during twilight, and by the end of the month it will set at the same time as the Sun. In fact, Neptune is now approaching the Sun, and will be in conjunction by the beginning of March.

Deep-Sky Objects

NGC 3169 and NGC 3166
Image Credit: ESO/Igor Chekalin

While most observers will be familiar with all, or most of the spectacular deep-sky objects that the constellations Cancer, Hydra and Leo offer, the little constellation Sextans contains some noteworthy deep-sky objects (DSOs) that may not be as familiar to many observers. One, or rather, two, such objects are NGC 3169 and NGC 3166.

This pretty pair of galaxies is separated by about 50,000 light years, which may sound like a lot but is nevertheless close enough for both galaxies to be affected by each other’s gravitational fields, as can be seen by their distorted shapes. Since the two galaxies are so close together, most investigators believe that they will eventually merge to form a single elliptical galaxy as opposed to merely pulling each other apart as they pass by one another.

The pair of galaxies is located about 70 million light years away and has a combined apparent visual magnitude of 10.3, which makes it a relatively easy target for medium-sized telescopes. Look for NGC 3169 and NGC 3166 just below the bright star Regulus in the constellation Leo.

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