The Major Planets in October 2011

In the early evening sky Venus gets a little higher while Mercury emerges from the Sun. It joins Venus by the end of the month when both set less than two hours after sunset. By the end of October, Jupiter will rise in the east before the other two planets set and will be visible all night. In the morning Mars still rises only a little over two hours before the Sun.

Saturn is at conjunction mid October and too close to the Sun to see all month.

The 5 naked eye Planets in October 2011

The usual notes on each planet for the month are on the left hand side of each section with a chart on the right.

The charts show the position or path of the planets for the month, unless the planet is too close to the Sun for observation, as is the case for Saturn during October. Stars to magnitude 5 are marked, with magnitudes for those brighter than 3.5 shown without a decimal point. The circle on each chart represents a field 10° in diameter, about the width of the 4 fingers of a hand held at arms length and twice the field of view of most binoculars.

The charts present a view as seen from mid latitudes in the southern hemisphere. The field shown in each chart is about 40° wide and 35° high. Star names are in white, constellation names in green.

All charts have been prepared using GUIDE 8 software published by Project Pluto

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MERCURY in October 2011
Mercury was at conjunction with the Sun at the end of September. During October it emerges from the Sun into the evening sky where it is likely to be visible from about the middle of the month. It will then set about an hour after the Sun. In mid October, Mercury will be about 4° below Venus, but will spend the rest of October catching up so that the two are side by side towards the end of the month. The much fainter Mercury, magnitude -0.3 will be some 2° to the left of Venus. Venus will be visible well before Mercury in the evening twilight. Once Venus can be seen, it should be possible to locate Mercury using binoculars. On the evening of October 28 the two planets are joined by the moon, a very thin crescent only 3% lit. The triple conjunction is shown on the chart for Venus. All three will be in the field of a pair of binoculars. Earlier in the afternoon of the 28th Mercury is occulted by the moon as seen from Australia and New Zealand. This is not visible to the eye, although moderate sized telescopes may make the event visible. However extreme care would be needed as the moon is only 18° from the Sun. Observation of the occultation should only be attempted by those familiar with observing these events.	The chart shows the path of Mercury, at first in Virgo but moving into Libra, from the 15th of October as the planet moves away from the Sun. The path of Venus is shown from the same date. On the 15th and 35 minutes after sunset, when Venus should be visible, the horizon will be about level with the bottom of the chart. On the 31st at an equivalent time after sunset, it will be about level with the star marked 273 (α Lib). Although stars are marked, only the brighter are likely to be visible, even at the end of the month.
VENUS in October 2011
Venus climbs further into the evening sky during October. It sets an hour after the Sun at the beginning of the month, an hour and three-quarters later at the end. The planet starts the month in Virgo, passing just under 3° from Spica, α Vir, magnitude 1.1, on the 4th. On the 16th Venus crosses into Libra. It is only 16', half the diameter of the full moon, from α Lib on the 21st. α Lib, also known as Zuben Elgenubi is, as might be expected, the brightest star in Libra. It is in fact a wide double star. The primary star, α2 Lib has a magnitude 2.7, the secondary, α1 Lib, is 5.2 so only 10% as bright. The two stars are nearly 4 arc-minutes apart, so would appear as separate objects to the unaided eye, were it not for the relative brightness of the two stars and, in this case, their low altitude. Using binoculars the best time to look for the double may be about an hour after sunset. By then Venus will be getting low, it sets about 90 minutes after the Sun, but the sky will be darkening. On October 21 Mercury will be 3° to the lower left of Venus. A week late Mercury will be almost up with Venus, a couple of degrees to its left. On the 28th the moon, a very thin crescent only 3% lit, will join the pair, 1.5° above and slightly to the left of Venus in the early evening sky. Again locating Venus in binoculars is likely to show the three as the sky darkens.	The chart shows the path of Venus in Virgo and Libra during October. As well as being marked on the 1st, Venus is shown in its position on the 28th along with the moon and Mercury. The bottom of the chart is at the level of the horizon on October 1 about 45 minutes after sunset. Venus should be visible well before that. By the end of October at the equivalent time the horizon will be close to the level of α Lib with Venus and Mercury 9° up.
MARS in October 2011
During October Mars rises in the morning a little over 2 hours before the Sun. So it remains best observed 45 minutes or more before sunrise when it will rather low to the northeast. Mars brightens slightly during the month, from magnitude 1.3 to 1.1. The planet starts the month in Cancer on the edge of the Praesepe (Beehive) star cluster, M44. Over the following two mornings it will cross the cluster. Mars will be near the centre of Praesepe on the morning of the second. The best views will be obtained through binoculars when the degree wide cluster will be seen peppered with 6th to 8th magnitude stars. Mars will move on into Leo on the 20th heading in the direction of Regulus, the brightest star in the constellation. On the morning of the 22nd, the 33% lit moon will be just over 5° above Mars.	The chart shows the path of Mars in the morning sky during October 2011. The view shows the sky on the morning of October 22 about 45 minutes before sunrise when the moon will be 5° above Mars. Early in the month some of the stars near the bottom of the chart up to about the bottom of the 10° circle will be below the horizon 45 minutes before sunrise. They all come into view as the month progresses.
JUPITER in October 2011
During October, Jupiter will be in Aries near its border with Cetus. The planet will move in a retrograde, westerly, direction about 4° during the month. Jupiter is at opposition on October 29 when it will rise close to the time of sunset, be due north and highest at local midnight, that is in the region of 1 to 1.30 am NZDT, and it will set close to the time of sunrise. Hence the planet will be quite well positioned for viewing by midnight early in October and a little earlier in the evening by the end of the month. On the night of October 13/14 the 98% lit moon will be just under 6° from Jupiter. At midnight they will be to the northeast with the moon to the left of and a little lower then the planet. By the morning of the 14th, before sunrise, the pair will be to the northwest, the rotation of the sky bringing the moon almost directly below Jupiter. At opposition Jupiter will be 594 million km, 3.97 AU, from the Earth and 4.96 AU from the Sun.	The chart shows the 4° path of Jupiter in Aries, near its border with Cetus and Pisces during October. Jupiter is marked at its position on October 13/14 when the 98% lit moon will be nearly 6° to the left of Jupiter. The chart shows the orientation of the sky at near midnight NZDT.
SATURN in October 2011 (not observable)
Saturn is at conjunction with the Sun on October 14 (NZ time) when it will be at the opposite side of the Sun to the Earth. It will be too close to the Sun to observe throughout the month. At conjunction Saturn will be to the north of the Sun, about 2° from its limb. In fact the planet will be 1447 million km, 9.67 AU,beyond the Sun and 10.67 AU or 1596 million km from the Earth. During October Saturn will appear to move about 4° through the stars. The Sun appears to move this distance in approximately 4 days. In reality this a reflection of the Earth's movement round the Sun, about 1° per day. On the chart, the line through the Sun represents part of the ecliptic, the apparent path it takes through the stars. The Sun's position 2 days before and after the conjunction are marked. The blue line through Saturn shows its movement during the whole of October. After conjunction Saturn will start rising in the morning sky before the Sun and become visible in the morning before sunrise during November.	The chart shows the position of Saturn relative to the Sun when at conjunction. The distance of Saturn from the Sun is in scale with the diameter of the Sun, but Saturn's size is greatly exaggerated. In reality, Saturn's diameter would appear to be only less than 1% of the Sun's.