Mercury reached inferior conjunction on January 30th and consequently was too close to the Sun to be observable. However, since the planet moves fast it takes less than two weeks before it reappears as a morning object for observers at tropical and Southern Hemisphere latitudes. Mercury then climbs higher in the sky each subsequent morning until peaking on February 24th, when it reaches greatest elongation west (26.7 degrees from the Sun). From northern temperate latitudes, the angle of the ecliptic is not favourable and during this time the planet is unsuitably placed for observation.
As often is the case with Mercury apparitions, one hemisphere of the Earth is favoured over the other. On this occasion it's the Southern Hemisphere with the added bonus that this also happens to be the most favourable morning apparition of the year. With an extended period of visibility the opportunity to spot the illusive planet over the next few weeks is superb.
For example, from latitude 35S (approx. equal to Sydney, Cape Town and Santiago) Mercury (mag. +0.3) will appear 13 degrees above the eastern horizon 45 minutes before sunrise on February 14th. The planets altitude continues to improve slightly each subsequent morning until February 24th when it peaks at 16 degrees above the horizon. Mercury shines at mag. 0.0 on this day.
The diagram below shows the February and March apparition of Mercury from latitude 35S. The thin waning crescent Moon passes 3.5 degrees north of Mercury on February 17th.
From northern temperate latitudes, Venus is a brilliant evening object visible above the west-southwestern horizon after sunset. At the start of the month the planet sets over 2 hours after the Sun from such latitudes increasing to over 3 hours by months end. Even though it's currently languishing towards the lower end of its brightness scale (mag. -3.9) Venus is always brighter than any other planet.
During September the phase of Venus decreases from 92% to 87% with the apparent diameter increasing marginally from 11 to 12 arc seconds. From the Southern Hemisphere, Venus appears low down above the western horizon and sets just over 1 hour after the Sun.
On February 21st, Venus passes less than 0.5 degrees south of Mars. At magnitude +1.3 the "Red planet" is over one hundred times fainter than brilliant Venus! The waxing crescent Moon is nearby on the same day making a lovely grouping in the early evening sky.
Mars remains an early evening object towards the west during February. The fourth planet from the Sun continues its rapid direct eastward motion against the background stars. It starts the month in Aquarius before crossing into Pisces on February 11th where it remains for the rest of the month. At magnitude +1.2, Mars is not that bright and there are currently 17 night-time stars brighter! Mars will be very close to Venus on the evening of February 21st with the Moon also nearby.
By months end, Mars sets 2.5 hours after the Sun from northern temperate latitudes but only 1 hour for those located further south.
Jupiter reaches opposition on February 6th and therefore visible all night. On this day, the giant planet rises in the east when the Sun sets in the west and then sets in the west as the Sun rises again for the new day. At magnitude -2.6, Jupiter is far brighter than any night-time star and unmistakable due to its brilliance.
This year at opposition, Jupiter is located 4.346 AU (650.18 million kilometers or 404.01 million miles) from Earth, which gives it an apparent size of 45 arc seconds. The planet is currently moving retrograde and spends the first few days of the month in Leo before crossing the constellation boundary into Cancer on February 4th. Jupiter's current declination of +16 degrees favours Northern Hemisphere based observers with the planet appearing higher in the night sky and visible for a longer period of time.
To the naked eye Jupiter appears creamy or off-white in colour. Unlike the brightest stars it doesn't twinkle at all. Compare the planet (or any other bright planet) with Sirius (α CMa - mag. -1.45) the brightest star in the night sky. Sirius twinkles and flashes many different colours particularly when close to the horizon but Jupiter doesn't twinkle at all.
A pair of 7x50 or 10x50 binoculars will reveal the planets disk although it's small. Also visible are Io, Europa, Ganymede and Callisto, the four large Galilean moons. As they orbit Jupiter they constantly change position; sometimes all four are visible but often some or all of the satellites will be temporarily obstructed and hidden as they pass behind or in front of Jupiter's disk.
When viewed through a telescope, Jupiter is an awesome sight. A 80mm (3.1 inch) scope shows the main northern and southern equatorial cloud belts and finer details along with the Galilean moons. Larger telescopes reveal much more detail including smaller belts, ovals, festoons, darkenings and of course the famous "Red Spot".
On February 4th, the full Moon passes 5 degrees south of Jupiter.
Saturn is now a morning object moving direct in northern section of Scorpius "the Scorpion". The planet is located a few degrees northwest of Antares (α Sco mag. +1.0) the brightest star in the constellation. Saturn is currently far better seen from the southern latitudes where by months end it rises well before midnight. From northern temperate locations Saturn rises around 1:30am at the end of February.
Saturn brightens from mag. +0.6 to +0.5 as the month progresses with its apparent size increasing marginally from 16 to 17 arc seconds. On February 13th, the last quarter Moon passes 2 degrees north of the planet.
Uranus, mag. +5.9, remains an early evening object during February. The distant ice giant is visible towards the west as soon as it's dark enough. The planet is easily visible with binoculars but by months end sets less than 3 hours after the Sun.
Uranus is currently located in Pisces close to the Cetus border and about 20 degrees southeast of the Great Square of Pegasus. At the end of the February, Venus (mag. - 3.9) and Mars (mag. +1.3) are less than 10 degrees southwest of the much fainter Uranus.
On February 21st, the waxing crescent Moon passes 0.3 degrees north of Uranus and an occultation is visible from southeast Canada and northeast America at 22:16 UT.
Neptune reaches solar conjunction on February 26th and therefore is not visible this month.
Solar System Data Table February 2015
|Date||Right Ascension||Declination||Apparent Magnitude||Apparent Size||Illum. (%)||Distance from Earth (AU)||Constellation|
|Sun||5th Feb 2015||21h 12m 24.0s||-16d 08m 48.2s||-26.8||32.4'||100||0.986||Capricornus|
|Sun||15th Feb 2015||21h 52m 04.1s||-12d 55m 55.1s||-26.8||32.4'||100||0.988||Capricornus|
|Sun||25th Feb 2015||22h 30m 32.5s||-09d 22m 01.2s||-26.8||32.3'||100||0.990||Aquarius|
|Mercury||5th Feb 2015||20h 21m 49.5s||-15d 50m 07.8s||2.4||10.0"||09||0.672||Capricornus|
|Mercury||15th Feb 2015||20h 14m 14.8s||-18d 00m 48.3s||0.3||08.3"||39||0.807||Capricornus|
|Mercury||25th Feb 2015||20h 46m 14.2s||-18d 03m 45.1s||0.0||06.9"||59||0.968||Capricornus|
|Venus||5th Feb 2015||22h 49m 08.2s||-09d 05m 11.7s||-3.9||11.2"||91||1.494||Aquarius|
|Venus||15th Feb 2015||23h 34m 43.1s||-04d 03m 32.3s||-3.9||11.5"||89||1.452||Aquarius|
|Venus||25th Feb 2015||00h 19m 25.1s||01d 08m 57.4s||-3.9||11.9"||87||1.405||Pisces|
|Mars||5th Feb 2015||23h 17m 45.5s||-05d 22m 36.7s||1.2||04.4"||96||2.129||Aquarius|
|Mars||15th Feb 2015||23h 46m 06.1s||-02d 12m 56.4s||1.2||04.3"||97||2.174||Pisces|
|Mars||25th Feb 2015||00h 14m 09.7s||00d 57m 01.3s||1.3||04.2"||97||2.218||Pisces|
|Jupiter||5th Feb 2015||09h 21m 35.5s||16d 27m 18.3s||-2.6||45.4"||100||4.346||Cancer|
|Jupiter||15th Feb 2015||09h 16m 21.6s||16d 52m 14.6s||-2.6||45.2"||100||4.358||Cancer|
|Jupiter||25th Feb 2015||09h 11m 24.8s||17d 14m 52.9s||-2.5||44.8"||100||4.401||Cancer|
|Saturn||5th Feb 2015||16h 07m 42.9s||-18d 54m 04.1s||0.6||16.3"||100||10.219||Scorpius|
|Saturn||15th Feb 2015||16h 09m 56.7s||-18d 58m 30.8s||0.6||16.5"||100||10.057||Scorpius|
|Saturn||25th Feb 2015||16h 11m 31.8s||-19d 01m 03.7s||0.5||16.8"||100||9.891||Scorpius|
|Uranus||5th Feb 2015||00h 49m 36.9s||04d 37m 29.1s||5.9||03.4"||100||20.515||Pisces|
|Uranus||15th Feb 2015||00h 51m 03.9s||04d 46m 56.6s||5.9||03.4"||100||20.652||Pisces|
|Uranus||25th Feb 2015||00h 52m 43.7s||04d 57m 41.0s||5.9||03.4"||100||20.770||Pisces|
|Neptune||5th Feb 2015||22h 33m 13.1s||-09d 53m 27.5s||8.0||02.2"||100||30.888||Aquarius|
|Neptune||15th Feb 2015||22h 34m 36.4s||-09d 45m 19.0s||8.0||02.2"||100||30.937||Aquarius|
|Neptune||25th Feb 2015||22h 36m 01.9s||-09d 36m 58.4s||8.0||02.2"||100||30.957||Aquarius|