Mercury
Mercury reaches greatest elongation east on February 16th and is visible as an evening object for observers in tropical and northern latitudes after the first week of the month. For northern hemisphere observers, this is the most favourable evening apparition of the year and therefore the best chance in 2013 to catch a glimpse of this illusive world after sunset. Unfortunately, Mercury is inconveniently placed for observation for observers located in southern temperate latitudes this month.
The diagram below shows the altitude of Mercury 45 minutes after sunset when viewed from latitude of 51.5N (e.g. London, England). A similar view exists to that shown for other northern temperate latitudes. The planet should be visible from about February 6th until a few days after February 20th. The best time to search for the planet is during the period when reaches its highest point in the sky on February 16th. On this date (greatest elongation east), 45 minutes after sunset Mercury will be 9 degrees above the horizon and shine at magnitude -0.7. Before this date, Mercury will be brighter and theoretically easier to locate, but on the other hand closer to the horizon.
Mercury Northern Hemisphere view - February 2013 - pdf format
For example on February 6th, Mercury shines at magnitude -1.1 but is only 4 degrees above the horizon, 45 minutes after sunset. The magnitude of Mercury decreases significantly as the month progresses and by February 26th, the planet will now shine at only magnitude +2.0. At this stage, the elongation of Mercury from the Sun is now rapidly decreasing and the planet is soon lost to the Suns glare before it draws into inferior conjunction early next month.
On February 8th, Mercury (mag. -1.0) passes only 0.3 degrees north of the much dimmer Mars (mag. 1.2).
Venus
The current morning apparition of Venus is now all but over as the planet draws towards the Sun and then onto next month's superior conjunction.
From northern temperate latitudes Venus is unobservable this month. Observers located in the tropics and more southerly latitudes may still be able to glimpse the planet low down just south of east in the dawn twilight sky. However, it won't be long before the Suns glare catches up and by the end of the month the planet will also be lost from these latitudes.
During February, the phase of Venus is almost full. It increases from 97% to 99%, while the apparent size hardly changes at around 10 arc seconds.
Mars
Mars is edging nearer to its April conjunction with the Sun and remains visible this month, although only as an extremely difficult evening object. At magnitude 1.2, it's not bright and chances to glimpse the famous "Red planet" are limited to the early part of the month. Come the second half of February and Mars will be lost to the bright evening twilight and hence unobservable.
On February 1st, Mars sets just over 1.5 hours after the Sun. The planet is positioned inconveniently low down, just a few degrees above the western / southwestern horizon. Normally, since Mars is so close to the Sun this month it could probably be forgotten about, but an interesting opportunity exists on February 8th to spot the planet.
On this day the much brighter Mercury (mag. -1.0) passes within 0.5 degrees of Mars. The best time to start looking for the two planets is about 30 minutes after sunset towards the western / southwestern horizon. As the sky darkens, the bright Mercury should be relatively easy to find and acts as the perfect marker to spot Mars. A pair of binoculars will significantly aid the search, but as always take extreme care when using binoculars at this time of day. The best advice is to start scanning when the Sun is well below the horizon so that you don't accidently look at it and risk permanent eye damage.
Jupiter
Jupiter remains a brilliant object in Taurus that's visible as soon as it's dark enough and remains visible until the early hours of the morning. The largest of all planets is located only 4.5 degrees north of magnitude 0.9 orange/red star Aldebaran and the famous "V" shaped Hyades open cluster. With M45, the beautiful Pleiades open cluster located just to the northwest; Jupiter currently lies in the "golden gate" section of the zodiac.
Jupiter in Taurus during February 2013 - pdf format
At the end of last month Jupiter reached its secondary stationary point signaling the end of its latest phase of retrograde motion. The planet is now once again moving direct. During February, its brightness fades from magnitude -2.5 to -2.3 but the planet remains unmistakable due to its brilliance. For comparison, even though Jupiter is fading, it is still about 20 times brighter than nearby Aldebaran!
The distance between Jupiter and the Earth is now increasing and consequently the apparent diameter of the planet is decreasing. During February, it decreases from 43 to 39 arc seconds.
On February 18th, the first quarter Moon passes 0.9 degrees south of Jupiter and an occultation is visible from southern Australia.
Saturn
Saturn is located amongst the faint stars of western Libra, only a few degrees from its border with Virgo. The planet is now going from strength to strength as it heads towards opposition in April.
At the start of February, Saturn rises just after midnight and by months end just before midnight. As well as the increased period of visibility, the planets apparent magnitude and diameter are also increasing. At the start of the month, Saturn shines at magnitude 0.6 and by the end of the month it's up to magnitude 0.4. During the same time period the apparent size increases slightly from 17 to 18 arc seconds.
Saturn in Libra in February 2013 - pdf format
This year, Saturn's beautiful rings are a fantastic sight; they appear wide open with an apparent tilt of 19 degrees when viewed from our perspective. Even a small telescope will easily show the rings; medium to large telescopes display them in full glory, along with subtle details on the planet's surface and many of its brightest moons.
On February 3rd, the last quarter Moon will pass 3 degrees south of Saturn.
Uranus
Uranus remains visible during February as an early evening object located in the constellation of Pisces. At the start of the month, Uranus sets about 4 hours after the Sun but by months end this is reduced to less than 3 hours. The magnitude of the planet is 5.9 and is therefore an easy binocular object or even naked eye object when viewed under dark skies.
The seventh planet from the Sun is positioned below the famous "Great Square of Pegasus" and moving towards the star 44 Piscium, which at magnitude 5.8 is fractionally brighter than Uranus.
On February 13th the waxing crescent Moon passes 4 degrees north of Uranus.
Neptune
Neptune is located in Aquarius and reaches solar conjunction on February 21st and therefore not visible this month.
Solar System Data Table February 2013
| Date | Right Ascension | Declination | Mag. | Size | Illum. (%) | Distance (AU) | Constellation | |
|---|---|---|---|---|---|---|---|---|
| Sun | 5th Feb 2013 | 21h 14m 28.5s | -15d 59m 26.7s | -26.8 | 32.4' | 100 | 0.986 | Capricornus |
| Sun | 15th Feb 2013 | 21h 54m 05.4s | -12d 45m 15.6s | -26.8 | 32.4' | 100 | 0.988 | Capricornus |
| Sun | 25th Feb 2013 | 22h 32m 29.1s | -09d 10m 35.4s | -26.8 | 32.3' | 100 | 0.990 | Aquarius |
| Mercury | 5th Feb 2013 | 22h 05m 24.1s | -13d 07m 39.4s | -1.1 | 05.5" | 89 | 1.234 | Aquarius |
| Mercury | 15th Feb 2013 | 23h 00m 52.3s | -05d 40m 09.8s | -0.8 | 06.8" | 59 | 0.994 | Aquarius |
| Mercury | 25th Feb 2013 | 23h 16m 33.7s | -01d 22m 10.5s | 1.6 | 09.2" | 15 | 0.732 | Pisces |
| Venus | 5th Feb 2013 | 20h 23m 40.4s | -20d 05m 58.7s | -3.9 | 10.1" | 98 | 1.656 | Capricornus |
| Venus | 15th Feb 2013 | 21h 14m 57.4s | -17d 03m 06.4s | -3.9 | 09.9" | 98 | 1.678 | Capricornus |
| Venus | 25th Feb 2013 | 22h 04m 17.1s | -13d 12m 16.7s | -3.9 | 09.8" | 99 | 1.695 | Aquarius |
| Mars | 5th Feb 2013 | 22h 17m 56.6s | -11d 39m 49.7s | 1.2 | 04.1" | 99 | 2.303 | Aquarius |
| Mars | 15th Feb 2013 | 22h 47m 39.7s | -08d 41m 32.0s | 1.2 | 04.0" | 99 | 2.324 | Aquarius |
| Mars | 25th Feb 2013 | 23h 16m 48.9s | -05d 35m 53.4s | 1.2 | 04.0" | 99 | 2.344 | Aquarius |
| Jupiter | 5th Feb 2013 | 04h 17m 40.8s | 20d 46m 33.3s | -2.5 | 42.4" | 99 | 4.652 | Taurus |
| Jupiter | 15th Feb 2013 | 04h 19m 08.8s | 20d 52m 23.8s | -2.4 | 41.0" | 99 | 4.808 | Taurus |
| Jupiter | 25th Feb 2013 | 04h 21m 57.9s | 21d 01m 15.6s | -2.3 | 39.7" | 99 | 4.969 | Taurus |
| Saturn | 5th Feb 2013 | 14h 38m 07.7s | -12d 49m 59.2s | 0.6 | 17.2" | 100 | 9.666 | Libra |
| Saturn | 15th Feb 2013 | 14h 38m 46.0s | -12d 50m 27.4s | 0.5 | 17.5" | 100 | 9.503 | Libra |
| Saturn | 25th Feb 2013 | 14h 38m 43.5s | -12d 47m 46.2s | 0.5 | 17.8" | 100 | 9.346 | Libra |
| Uranus | 5th Feb 2013 | 00h 21m 40.1s | 01d 35m 51.4s | 5.9 | 03.4" | 100 | 20.683 | Pisces |
| Uranus | 15th Feb 2013 | 00h 23m 17.2s | 01d 46m 37.4s | 5.9 | 03.4" | 100 | 20.804 | Pisces |
| Uranus | 25th Feb 2013 | 00h 25m 05.2s | 01d 58m 29.1s | 5.9 | 03.4" | 100 | 20.904 | Pisces |
| Neptune | 5th Feb 2013 | 22h 16m 59.1s | -11d 19m 11.6s | 8.0 | 02.2" | 100 | 30.937 | Aquarius |
| Neptune | 15th Feb 2013 | 22h 18m 24.6s | -11d 11m 11.9s | 8.0 | 02.2" | 100 | 30.971 | Aquarius |
| Neptune | 25th Feb 2013 | 22h 19m 51.3s | -11d 03m 05.8s | 8.0 | 02.2" | 100 | 30.977 | Aquarius |