SKYWATCH – FEBRUARY
PLANETS
This is a good month for planets, with only Neptune missing. MERCURY orbits close to the Sun, but is visible in the west after sunset towards the end of this month, very low to the horizon, a little bright dot. (NB Do not observe it until after the Sun has set.) Distant URANUS is the next planet up from the western horizon, and will be easiest to find for a few days around the 9th, when it will be very close to Venus. VENUS is climbing ever higher and brighter and will be visible up to 10pm by the end of the month. Observe as dusk falls to see its lunar-like shape. Following Venus is JUPITER, with its four principle moons on show, still wonderful to behold, but now setting around midnight. With Venus and the crescent Moon, it makes a photogenic display 25th-26th.
MARS is rising in the east at around 8.30pm at the beginning of the month and around 5.30pm by the end of it. It is getting much closer and brighter, so this is a very good time to observe it; it will be at Opposition next month and can be seen all night. Look for ice caps on the poles; the hemisphere experiencing summer will have a smaller one. Markings on the planet indicate different geological features and can be seen with larger telescopes – providing one of Mars’ frequent red dust-storms doesn’t obscure them.
SATURN is the last planet to rise, around midnight; but will become an evening object for the next few months.
BRIGHTNESS
Stars are described in terms of their ‘apparent magnitude’ – literally how bright they seem to us, viewing them from Earth. Naked eye, we can see up to 6th magnitude; binoculars and telescopes enable us to see far more fainter ones. On star maps the relative brightness (0 to 5) is shown by size, with magnitude 0 (very bright) shown as a large dot. Sirius, the brightest star in the sky, is the only one with a negative number (-1.4).
Some planets, when close in their orbits to Earth, become even brighter and are also represented by negative numbers. Venus, a close neighbour, always has a negative number, which varies according to its position. By the end of this month it will be -4.1, the brightest object in the sky. Second is Jupiter, at -2.2. Mars as it gets closer goes from -0.5 to -1.2. By contrast, Uranus, very distant, is +5.9 (only just visible, in principle, naked eye); and Saturn is currently +0.6, so we usually use its colour to distinguish it from the alpha star of the host constellation.
OBSERVING GROUP
As usual, we will meet at 8pm inside The Red Lion, Kilmington. Newcomers welcome.
Article supplied by MC2 Telescope Shop, 57 Catherine Street, Frome