THE SOUTHERN HEMISPHERE
With Glenn Dawes
Explore the surface features of Mars while it’s at opposition and enjoy a pair of edge-on spiral galaxies
When to use this chart
1 Oct at 24:00 AEST (14:00 UT) 15 Oct at 23:00 AEDT (12:00 UT) 31 Oct at 22:00 AEDT (11:00 UT)
OCTOBER HIGHLIGHTS
October belongs to Mars. Most of the time its small angular size (averaging around 10 acrseconds) makes it tricky for us to glimpse surface features like mountain ranges, volcanos, valleys and plains, but this month we’ll see the Red Planet at opposition and at closest approach reaching 22.4 arcseconds in the eyepiece – its most favourable apparition until 2033. Mars is fascinating to observe, presenting a different nightly view and with dust storms altering its appearance.
THE PLANETS
Mars dominates the early eastern evening sky and is visible all night; it’s at maximum brightness and now rivals that of Jupiter, which along with Saturn, resides in the northern evening sky. While Mercury’s evening sky return ends as it dives back into
DEEP-SKY OBJECTS
Take a ride on Pegasus this month, as Eta Pegasi (RA 22h 43.0m, dec. +30° 13’) is easily visible to the unaided eye. A small scope shows a colourful wide double star with a bright (mag. +2.9) yellow primary and a distant (99” away) faint mag. +9.9 blue companion.
Next, we visit two edge-on spiral galaxies. NGC 7332 (RA 22h 37.4m, dec. +23° 48’) is easily found between two
The chart accurately matches the sky on the dates and times shown for Sydney, Australia. The sky is different at other times as the stars crossing it set four minutes earlier each night.
STARS AND CONSTELLATIONS The constellation of Grus the Crane has two prominent stars, Alpha (Alnair) and Beta (Alphaulka) Gruis. From the Northern Hemisphere this bird can be visualised as walking along the southern horizon. Although the stars mark the position of its feet, these common names relate to when Grus was part of Piscis Austrinus’s fish. The cool M-type red giant star Beta Grui presents quite a colour contrast to nearby Alpha, which is a hot B-type bluish-white star. the Sun’s glare late in October, Neptune is well placed for observing as its due north at 22:00 mid-month, with its fellow outer Solar System companion, Uranus, following three hours later. Meanwhile, Venus continues to dominate the predawn eastern sky. isolated (7th magnitude) stars, 0.5° apart. At mag. +11.1 the galaxy has a bright star-like nucleus with an elongated core, surrounded by a fainter, but elliptical halo (around 2’ x 0.5’) orientated almost north to south. Easily fitting in the same eyepiece view is NGC 7339, only 0.1° east. This has a similar shaped halo, but is fainter without noticeable brightening at the centre. NGC 7339’s east to west orientation makes it point towards 7332.
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