Mercury is currently located on the far side of the Sun. The innermost planet passes through superior conjunction on February 16th. Throughout the month it remains too close to the Sun to be safely observed.
Venus returns to the evening sky for the first time since March 2017. The brilliant planet shines at mag. -3.9 and can be seen during twilight from northern locations, very low above the western horizon towards the end of month. However, those living further south will struggle to spot the planet.
Mars is an early morning object that continues to move rapidly eastwards this month. The "Red planet" starts the month at mag. +1.2 in Scorpius, a fraction of a degree south of Acrab (β Sco mag. +2.6). It then crosses into Ophiuchus on February 8th, where it remains for the rest of the month. On February 9th, the waning crescent Moon passes 4 degrees north of Mars and on the following day, Mars passes 5 degrees north of red supergiant Antares (&alpha Sco - mag. +1.0). To the naked eye, this star and Mars will appear almost identical in colour and brightness. By months end, Mars will have brightened to mag. +0.8. It's apparent diameter improves marginally from 5.6 to 6.6 arc seconds as the month progresses.
From northern temperate locations, Mars rises above the southeastern horizon about 4 hours before the Sun. The visibility period is considerably better for those at southern latitudes, where Mars rises just after midnight by months end. Also located in the same region of sky are Jupiter and Saturn. Mars starts the month 12 degrees southeast of much brighter Jupiter (mag. -2.1), but by months end the pair are separated by more than 26 degrees. As Mars distances itself from Jupiter it moves closer to Saturn, and on the last day of February, Mars and Saturn will be 15 degrees apart. On this day, Mars shines at mag. +0.8 and therefore is only marginally fainter than, mag. +0.6, Saturn. However, there is no chance of mistaking the pair. Mars has a deep orange hue, while Saturn is creamy white in colour.
Although the apparent diameter of Mars is still small, telescopes on nights of good seeing should be able to make out larger surface markings. A useful tip is to push up the magnification as high as seeing allows, as the planet will take it.
Jupiter is now a brilliant morning object moving direct in Libra. From northern locations, the giant planet rises early morning at start of the month, improving to a couple of hours after midnight by months end. It remains visible until dawn. With a declination of 17 degrees south of the celestial equator, Jupiter is better placed for observers at southern and tropical locations, where the visibility period is considerably longer. By end of month from such locations, Jupiter rises before midnight.
As the month progresses, Jupiter increases from mag. -2.0 to -2.2 with its apparent size improving from 36 to 39 arc seconds. Through a pair of binoculars the four large Galilean moons, Io, Europa, Ganymede and Callisto are readily visible. They change position as they orbit the planet and sometimes all four can be seen at once, but often some are obscured from view as they pass in front of, or behind, the Jovian disk. Occasionally none can be seen.
When viewed through a telescope, Jupiter is a stunning sight. Even a small 80mm (3.1 inch) refractor will show the main northern and southern equatorial cloud belts. Larger telescopes reveal subtle details. With time and patience features such as small belts, ovals, festoons, dark regions and of course the famous "Great Red Spot" can be seen.
As previously mentioned fainter, Mars is positioned southeast of Jupiter. Further southeast of Mars is Saturn, and just before sunrise, on February 9th, 10th and 11th the waning crescent Moon will also be in the same region of sky, providing pleasant early morning viewing.
Saturn, mag. +0.6, is an early morning object in Sagittarius. The planet is just north of the constellation's "teapot" asterism among the rich Milky Way star fields. From mid-northern latitudes it's somewhat hindered by low altitude, but by month's end rises some 2.5 hours before the Sun. The planet is much better placed from southern locations, appearing higher in the sky and with a longer visibility period. From such locations by month's end, it rises less than a couple of hours after midnight.
As mentioned above, Mars moves closer to Saturn as the month progresses. On February 11th, the waning crescent Moon passes 2.5 degrees north of the planet.
Uranus, mag. +5.9, remains an early evening binocular object. The seventh planet from the Sun, and the first to be discovered in the telescope era, is moving slowly direct in Pisces. It's visible towards the west with binoculars and small telescopes as soon as it's dark enough. Uranus can be found close to the Aries constellation border and a few degrees west of omicron Psc (ο Psc - mag. +4.3). For those located at mid-northern latitudes the planet can be seen for some 5 hours on February 1st, reducing to around 3 hours by months end. From southern locations, its visibility period is only about half as much.
On February 20, the thin waxing crescent Moon passes 5 degrees south of Uranus (Feb 2nd).
Neptune is located in Aquarius. The distant ice giant is heading towards solar conjunction, which it reaches on March 4th. Throughout the month it's positioned inconveniently close to the Sun, and therefore not suitably placed for observation.
Solar System Data Table - February 2018
|Date||Right Ascension||Declination||Mag.||App. Size||Illum. (%)||Dist. (AU)||Constellation|
|Sun||Feb 01||20h 57m 07.3s||-17d 14m 32.5s||-26.8||32.5'||100||0.985||Capricornus|
|Sun||Feb 15||21h 52m 59.2s||-12d 51m 05.5s||-26.8||32.4'||100||0.988||Capricornus|
|Sun||Feb 28||22h 42m 45.0s||-08d 09m 32.4s||-26.8||32.3'||100||0.990||Aquarius|
|Mercury||Feb 01||20h 12m 08.9s||-21d 43m 33.8s||-0.6||4.9"||95||1.382||Capricornus|
|Mercury||Feb 15||21h 48m 08.9s||-15d 27m 21.0s||-1.5||4.8"||100||1.394||Capricornus|
|Mercury||Feb 28||23h 17m 53.4s||-05d 37m 18.4s||-1.4||5.3"||94||1.278||Aquarius|
|Venus||Feb 01||21h 20m 30.5s||-16d 56m 42.7s||-3.9||9.8"||100||1.702||Capricornus|
|Venus||Feb 15||22h 28m 46.3s||-11d 06m 41.8s||-3.9||9.9"||99||1.687||Aquarius|
|Venus||Feb 28||23h 29m 17.1s||-04d 49m 12.1s||-3.9||10.0"||98||1.665||Aquarius|
|Mars||Feb 01||16h 04m 47.0s||-20d 08m 36.0s||1.2||5.6"||91||1.671||Scorpius|
|Mars||Feb 15||16h 40m 40.1s||-21d 41m 52.0s||1.0||6.1"||90||1.537||Ophiuchus|
|Mars||Feb 28||17h 14m 01.9s||-22d 43m 00.2s||0.8||6.6"||89||1.412||Ophiuchus|
|Jupiter||Feb 01||15h 15m 30.4s||-16d 55m 59.5s||-2.0||35.9"||99||5.497||Libra|
|Jupiter||Feb 15||15h 20m 26.4s||-17d 12m 45.7s||-2.1||37.4"||99||5.270||Libra|
|Jupiter||Feb 28||15h 23m 00.4s||-17d 20m 17.8s||-2.2||38.9"||99||5.062||Libra|
|Saturn||Feb 01||18h 19m 51.8s||-22d 28m 44.7s||0.6||15.3"||100||10.832||Sagittarius|
|Saturn||Feb 15||18h 25m 39.7s||-22d 25m 43.9s||0.6||15.6"||100||10.671||Sagittarius|
|Saturn||Feb 28||18h 30m 15.7s||-22d 22m 38.7s||0.6||15.8"||100||10.491||Sagittarius|
|Uranus||Feb 01||01h 32m 18.9s||09d 03m 03.4s||5.8||3.5"||100||20.167||Pisces|
|Uranus||Feb 15||01h 33m 53.9s||09d 12m 44.1s||5.9||3.5"||100||20.387||Pisces|
|Uranus||Feb 28||01h 35m 49.4s||09d 24m 16.2s||5.9||3.4"||100||20.565||Pisces|
|Neptune||Feb 01||22h 56m 59.3s||-07d 41m 35.2s||8.0||2.2"||100||30.787||Aquarius|
|Neptune||Feb 15||22h 58m 49.7s||-07d 30m 11.2s||8.0||2.2"||100||30.887||Aquarius|
|Neptune||Feb 28||23h 00m 38.3s||-07d 19m 01.7s||8.0||2.2"||100||30.931||Aquarius|