Starwatch: The February night sky

If our February evening sky provides a feast of stellar interest, then Jupiter serves as its appetiser. The giant planet, conspicuous at mag –2.2, lies some 30° high in the SW at nightfall tonight and sets in the W about 30 minutes before the chart times. It also stands lower each day, so the opportunities for studying its disc are dwindling, just as the main belt of cloud in its S hemisphere, the SEB, is recovering its dark hue. Look for the young Moon to the right of Jupiter on the 6th and above it a day later. Orion and his retinue of winter constellations, though, are the stars of February evenings. From the SE at nightfall, the Hunter marches across the meridian an hour before our map times, just as the star Capella soars overhead. Leading Orion is Taurus with the Pleiades star cluster, while trailing is Canis Major and Sirius, the brightest star in our night sky. Sirius owes its status to its distance of only 8.6 light years and its luminosity of 21 times that of our Sun. In contrast, all the main stars of Orion are hundreds of light years from us and blaze with hundreds or thousands of Sun-power. Saturn, mag 0.6, rises in the E one hour after our map times and lies 8° above the slightly fainter Spica in Virgo. The two stand highest in the S at 04:30 tomorow. so the predawn hours are best for telescopic views of the planet. The rings appear 41 arcsec wide tomorrow; their N face tipped 10° Earthwards. The disc is 18 arcsec across and usually has only subdued cloud bands. However, observers have been watching white clouds expand around its N hemisphere since a storm erupted there two months ago. Venus rises in the SE shortly after 05:00 and is brilliant but low down before dawn. Fading from mag –4.3 to –4.1, it is sliding eastwards to the N of the Teapot of Sagittarius and sports a dazzling gibbous disc if viewed telescopically. Spot it to the left of the waning Moon on the 28th. February diary 3rd 02h New moon 4th 17h Mars in conjunction with Sun 7th 10h Moon 7˚N of Jupiter 11th 07h First quarter; 22h Moon 1.4˚S of Pleiades 16th 23h Moon 4˚S of Praesepe 19th 09h Full moon 21st 17h Moon 8˚ S of Saturn 22nd 01h Moon 2.8˚ S of Spica 24th 23h Last quarter. 25th 06h Moon 2.8˚N of Antares; 09h Mercury in superior conjunction