Dundee Astro - Planetary Notes

By 01 March, Mercury will first appear somewhat higher, perhaps 10 degrees or so for mid-UK latitudes, but will be reduced to -1.0 magnitude; look for it from 18.00UT a little south of due-west. On that date it will sit below the much brighter Venus, with the very new moon (4% illuminated) sitting roughly midway between the two planets. Greatest Eastern (evening) Elongation (GEE) is on 08 March when Mercury will become visible to the eye from perhaps 18.15UT, still sitting below brilliant Venus but at around 12 degrees above the horizon, just less than 50% illuminated and shining at magnitude -0.4. After this Mercury sinks back towards the Sun with inferior conjunction on 24 March.

As mentioned, Venus is a beautiful early evening object, appearing shortly after sunset, high in the south-west. On 01 February look for the 12.5% illuminated new Moon, some 30 degrees high, from around 16.45UT; Venus will sit directly above it and some 5 degrees higher. At a dazzling -4.7 magnitude, the planet will be very obvious. Venus will show a 37% illuminated phase and will be 32 arcseconds (32”) in apparent size. Venus follows the evening rise of the ecliptic through most of February but by early March will start to appear noticeably lower, and closer to due-west, as it sinks steadily back towards the Sun; Look for it then from around 18.00UT, more than 20 degrees high in the west.

Inferior conjunction is on 23 March however on this occasion Venus passes some 8 degrees above the Sun, so while it sets in bright early twilight on that date, it can be seen to rise again as a morning object around 05.05UT, some 50 minutes ahead of the Sun on the 24th (for mid-UK latitudes).

Mars is visible for most of the night hours in February and should be observed once you have had your fill of nearby Jupiter. Mars passes due-south (transit) around 22.40UT early in the month, at more than 60 degrees above the horizon. It sits at the heart of Gemini, the twins, shining at -1.1 magnitude with a visible disk just under 14” across. By the first days of March, south-transit is at 20.40UT with apparent size reduced to just below 11” and brightness to -0.3, however it will be convenient to observe it during the mid-evening hours and it will not set until very early morning’s nautical-twilight. Even in late March, south-transit will be in early evening twilight and the planet can be followed at over 30 degrees of elevation until around midnight UT.

Jupiter sits in Taurus and therefore moves across the sky ahead of Mars. Early in February it transits around 19.50UT, again around 60 degrees high. At -2.1 magnitude it will be very obvious and at 43” across it will be large target showing masses of detail on nights of steady seeing. On 02 March Jupiter is at east-quadrature so shadow-transits of its moons will be well highly displaced from the moons themselves. South transit will be in early twilight, around 18.00UT, but Jupiter will still appear very high and will stay above 30 degrees high until 22.30UT so remains an excellent target. By late March, look for Jupiter some 45 degrees up in the south-west from twilight and follow it a while, before switching to Mars.

Saturn is moving closer to the Sun from our perspective but is visible in the south west shortly after sunset in early February; on the first it sits below Venus and the young New-Moon (12.8% illuminated). As mentioned it also sits very close to Mercury on 25 February but this will be a challenging pairing to see without a very clear and unobstructed western horizon. Solar conjunction is 12 March and, from Earth’s point of view, we will cross the plane of Saturn’s ring system on the 23rd, but this will be near impossible to observe safely from the UK due to the Sun’s proximity.

Uranus sits around 17 degrees ahead of Jupiter initially, so transits in early darkness, around 18.30UT, in early February and is best observed in the first couple of weeks of the month. At magnitude +5.7, it can be found 8 degrees below and to the right (west) of M45, the Pleiades cluster, and will show a disk 3.6” across. If seeing conditions are very good it will be worth seeking it out before moving on to Jupiter. By early March Uranus will transit in daylight but can still be found, sinking towards the south west, from perhaps 19.00UT, nearly directly below M45 and perhaps 45 degrees above the horizon. By late March it will be only 20 degrees up, due-west at 20.00UT.

Neptune sits close to Venus early in February so you will have to work hard to glimpse (telescopically) its 2.2” disk shining at a dim magnitude of +7.8. It will be 3 degrees below and slightly south (left) of Venus but that planet will swamp your view of Neptune if it is in the same eyepiece view. Conjunction with the Sun is on 19 March so Neptune is rapidly lost in early February and won’t be properly visible again until the autumn.