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Society for Popular Astronomy
Looking Forward to the Planets in February/March 2024
From the UK, Mercury starts February as a morning object, below and left (north) of more obvious Venus, itself low in the south east. Use Venus as a marker to see the fainter planet by sliding back along the line of the ecliptic some 13 degrees, early in the month, and you may find the closest planet to the Sun and follow it till sunrise. Mercury is falling in size and brightening slowly as it draws ever closer to the Sun, passing behind it (superior conjunction) on 28 February.
While the end of this morning apparition is disappointing, Mercury then goes on to give its best evening apparition of the year for the Northern hemisphere. Greatest Eastern (evening) Elongation from the Sun occurs on 24 March and for a week or so either side of this date Mercury will first appear, initially, 10 degrees high, almost due-west, for mid-UK observers; By the 24th this will be closer to 13 degrees and you will be able to follow the planet, each evening, to the end of the month and beyond.
Venus is also moving towards the end of its morning apparition but at magnitude -4, or just under, it will be very prominent in morning twilight and show a waxing gibbous phase, 85% illuminated in early February and 95% late in March, but by then it may be too low at sunrise to find before being lost to daylight. If found it can readily be followed into full daylight and observed at higher altitudes but from mid-March the planet is getting dangerously close to the Sun so all safety precautions must be made to prevent eye or equipment damage. For a few days either side of 22 February Venus sits just above Mars and the pair can be followed together in low powered eyepieces. The same is true for Saturn around 21 March but, again, great care must be taken with the nearby Sun.
Mars itself can be found between Venus and Mercury in early February, but at magnitude +1.23 it will be much fainter than either and hard to see. By early March, Mars rises just ahead of Venus and your best chance is to follow Venus into daylight, at higher altitudes then scan some 3 or 4 degrees to the right (south) along the ecliptic, to catch its tiny red disk. At under 5 arcseconds in apparent size you are unlikely to glimpse detail.
Jupiter starts February as an excellent evening target, just as darkness falls. South-transit is in early twilight and at more than 50 degrees of elevation for much of the UK population; the planet can then be followed until after midnight, showing a disk just under 40 arcseconds across. On a steady night the detail should be magnificent. At magnitude -2.34 it will be very obvious in an area sparse of bright stars between Menkar in Cetus and Hamal in Aries.
By early March Jupiter will have subsided noticeably towards the south-west as darkness falls, but will still be seen around 40 degrees high and can be followed above 30 degrees high for at least an hour, so is till well worth seeking out. By late March Jupiter will be below 20 degrees high in the west as darkness falls, so is best sort out early in the period.
As mentioned, Saturn is a morning object late in the period but starts February at low altitude in the south-west, and visible shortly after sunset. It is then rapidly lost to the Sun, passing behind it on 28 February. Thereafter, the best chance of seeing Saturn is by using Venus as a guide a little before sunrise on 21 March or for a day or so either side.
Of the ice-giants, Uranus is very well placed early in the period, trailing Jupiter by some 12 degrees along the line of the ecliptic and can be found just below the mid-way point of a line drawn between Jupiter and The Pleiades (M45). At under 4 arcseconds in apparent size and at magnitude +5.8, you will need to scan this area for a ‘green’ star and then add magnification to see its visible disk. Recent published research suggests that Uranus and Neptune are pretty much exactly the same colour but Neptune has always looked bluer to me. Perhaps this is a colour perception issue as Neptune is very significantly dimmer in brightness. Like Jupiter, Uranus is a good target into early March, sitting even higher than its neighbour, along the ecliptic, but will be washed out by twilight later in the period.
Neptune itself will be a low altitude target, hard to find and observe amongst the faint stars between the tail of Cetus and the lower fish head of Pisces; but if you wish to do so, dedicated finder charts are available on-line. Look for Neptune as early as possible as it moves behind the Sun in mid-March.