SkyEye

Welcome to SkyEye, your guide to this month's celestial events.

October 2009

All times and dates are given in Universal Time (UT).
Nightly darkness estimates are calculated for 45° N and 30° S.
Like total solar eclipses, lunar occultation events can be seen only from limited regions on Earth (and sometimes not at all if the occultation takes place during daylight hours). However, the Moon will appear close in the sky to its "target" for some hours either side of the actual occultation, regardless of where you are.

Date		Event
1	Thu
2	Fri
3	Sat
4	Sun	This Full Moon is the one closest to the September equinox, making this a "Harvest Moon."
5	Mon
6	Tue
7	Wed	Moon occults the Pleiades: visible from about 1830 in parts of southern and eastern Africa, southern Arabian Penninsula, southern Asia and the Philippine Sea.
8	Thu	The waning gibbous Moon interferes with viewing the Draconids.
9	Fri
10	Sat
11	Sun	Last Quarter Moon
12	Mon	Moon occults the Mars: visible in the southern ocean below India.
13	Tue	Moon at perigee
14	Wed
15	Thu
16	Fri
17	Sat
18	Sun	New Moon
19	Mon
20	Tue
21	Wed	Unlike the meteor shower earlier this month, dark skies await observers of the Orionids.
21	Wed	Moon occults Antares: visible from about 1530 UT in eastern and southeastern Europe.
22	Thu
23	Fri
24	Sat
25	Sun	Moon at apogee
26	Mon	First Quarter Moon
27	Tue
28	Wed
29	Thu	Mars at west quadrature
30	Fri
31	Sat

The Solar System

The word planet is derived from the Greek word for "wanderer." Unlike the background stars, planets seem to move around the sky, keeping mostly to a narrow track called the ecliptic, the path of the Sun across the stars. Dwarf planets and small solar-system bodies including comets, are not so constrained, often moving far above or below the ecliptic.

Sun: Virgo -> Libra
Mercury: Leo -> Virgo
Southern hemisphere observers barely catch a glimpse of this tiny planet in the dawn sky but those in the north get their best views this year of Mercury as a morning sky object. It reaches greatest elongation west on 6 October and heads back towards the Sun, vanishing very early in the month for those in the south but lingering until late October for northerly observing positions.
Venus: Leo -> Virgo
The "morning star" is still quite high in the east when viewed from the northern hemisphere but is much closer to the horizon for those observing it from southern latitudes. It continues to lose altitude throughout the month.
Mars: Gemini -> Cancer
Now rising before midnight, the red planet is occulted by the Moon on 12 October and reaches west quadrature on 29 October. Look for it passing through the Beehive open cluster at the end of the month.
Jupiter: Capricornus
The largest planet in the solar system is practicially stationary in the sky this month. Along with Neptune it sets a little after midnight.
Saturn: Virgo
The ringed planet is close to Mercury and Venus in the dawn sky early this month.
Uranus: Pisces -> Aquarius
At opposition last month, this green-coloured gas giant sets before dawn.
Neptune: Capricornus
A small telescope is necessary to view the most distant planet in the solar system which sets just after midnight.

The Celestial Sphere

Constellations are patterns of stars in the sky. The International Astronomical Union (IAU) recognises 88 different constellations. The brightest stars as seen from the Earth are easy to spot but do you know their proper names? With a set of binoculars you can look for fainter objects such as nebulae and galaxies or some of the closest stars to the Sun.

Descriptions of the sky for observers in both the northern and southern hemispheres are available for the following times this month. Subtract one hour from your local time if summer (daylight savings) time is in effect.

Local Time	Northern Hemisphere	Southern Hemisphere
1730 hours (1830 hours summer time)	45° N	30° S
1930 hours (2030 hours summer time)	45° N	30° S
2130 hours (2230 hours summer time)	45° N	30° S
2330 hours (0030 hours summer time)	45° N	30° S
0130 hours (0230 hours summer time)	45° N	30° S
0330 hours (0430 hours summer time)	45° N	30° S
0530 hours (0630 hours summer time)	45° N	30° S

For More Information...

Consult our online glossary for non-technical explanations of many of the astronomical terms used in these pages.
Blue moons, eclipses, the dates of Easter and much more can be found at the Interactive Astronomy Pages.
For more information about the objects and events described in SkyEye, visit these astronomy-related sites.

Credits

Much of this information can be found in this month's issue of your favourite amateur astronomy magazine available in your local bookshop. Another excellent source is the current edition of the Astronomical Calendar by Guy Ottewell and published by the Universal Workshop at Furman University.

The SkyEye banner features a view of Saturn from its satellite Iapetus and is courtesy of NASA/JPL/Space Science Institute. Of all the major satellites of Saturn, Iapetus is the only one with a significant orbital inclination. Thus, whilst the rings appear nearly edge-on from all of the other major satellites, from Iapetus they are usually seen at a tilt. This image was taken during the Cassini-Huygens mission on 10 September 2007 and consists of 15 red, green and blue spectral filter images.