The Planets
Mars
Best time to see: 15 October, 20:30 BST (19:30 UT) Altitude: 17º Location: Capricornus Direction: South Features: Dark markings, polar caps Equipment: 150mm or larger
Mars is an evening object in Capricornus at the start of October, looking like a bright orange star at mag. –1.3. Through a telescope it presents a 15 arcsecond disc, large enough to show some of the more prominent surface features through the eyepiece. By the middle of October, Mars will have moved to sit right at the middle of the triangular midsection of Capricornus.
The planet is slowly gathering altitude and on 15 October reaches 17° altitude as seen from the centre of the UK. Through a telescope, Mars is shrinking and by 15 October appears just 13 arcseconds across. It’s dimming too, dropping to mag. –1.0 by the middle of the month. On 16 October, Mars appears to sit 2 arcminutes from mag. +4.8 Eta (d) Capricorni, before passing 2.5° south of mag. +4.0 Theta (e) Capricorni on 17 October, 1.3° south of mag. +4.3 Iota (f) Capricorni on 25 October and 4.7° north of mag. +3.8 Zeta (c) Capricorni on 27 October. A waxing gibbous Moon sits nearby on 17 and 18 October.
By the end of October, Mars appears close to the pair of stars marking the
eastern extent of Capricornus; Gamma
(a) Capricorni and Delta (b) Capricorni. It now attains an altitude of 20° from the centre of the UK, twice what it managed when at opposition back in July. On 31 October Mars appears at mag. –0.6 with an 11 arcsecond disc.
In June, a number of dust storms whipped their way across the Martian sphere, diminishing the appearance of many of the dark markings that usually feature on Mars’s globe. The primary cause of these storms was Mars being close to perihelion, the closest point in its orbit to the Sun. They proved remarkably resistant through August, extending NASA’s Opportunity Mars rover’s radio silence to over two months. Will they have subsided by October? Only time will tell.