SkyEye

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

October 2010

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	Fri	Saturn at conjunction
1	Fri	Last Quarter Moon
2	Sat
3	Sun
4	Mon
5	Tue
6	Wed	Perigee
7	Thu	New Moon
8	Fri	Moonless skies make this an excellent year for observing the Draconids (theoretical peak activity: from 15:00 UT until 07:30 UT tomorrow).
9	Sat
10	Sun
11	Mon
12	Tue
13	Wed
14	Thu	First Quarter Moon
15	Fri
16	Sat
17	Sun	Mercury at superior conjunction
18	Mon	Apogee
19	Tue
20	Wed
21	Thu	The nearly full Moon obliterates the Orionids.
22	Fri
23	Sat	Full Moon
24	Sun
25	Mon
26	Tue
27	Wed
28	Thu	103P Hartley 2 at perihelion
29	Fri	Venus at inferior conjunction
30	Sat	This is the second Last Quarter Moon to occur this month.
31	Sun

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: Virgo » Libra
The smallest planet in the solar system is largely lost in solar glare at the beginning of the month, with superior conjunction occurring on 17 October. It reappears low in the west after sunset at the end of the month.
Venus: Libra » Virgo
The "evening star" is quite low as seen from northern latitudes but is quite high in the west early in the month for southern hemisphere observers. It soon plummets toward the horizon and its date with the Sun (inferior conjunction) on 29 October.
103P/Hartley 2: Cassiopeia » Perseus » Camelopardalis » Perseus » Auriga » Gemini » Monoceros
This comet was discovered in 1986 by Malcolm Hartley at the Siding Spring Observatory. It has a period of 6.4 years and its perihelion distance is just over 1 AU. This year's return is a very favourable one, with perihelion occurring just eight days after closest approach to Earth, and should be at least magnitude 4 or 5. The comet appears in Auriga at closest approach and near the star mu Geminorum at perihelion. Interestingly, the Deep Impact spacecraft, which visited comet 9P/Tempel 1 in July 2005, will rendezvous with this comet next month.
Mars: Libra » Scorpius
It is getting increasingly difficult to see this planet low in the west during evening twilight.
Jupiter: Pisces » Aquarius
The largest planet in the solar system was at opposition last month, so it is still visible for most of the night, setting before sunrise.
Saturn: Virgo
The ringed planet is at conjunction on the first of the month, reappearing low in the east at sunrise by the end of the month.
Uranus: Pisces
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 collision of galaxy clusters and is courtesy of NASA, ESA, CXC, M. Bradac (University of California, Santa Barbara) and S. Allen (Stanford University). When MACS J0025.4-1222 was formed, gravity caused the ordinary matter in the colliding galaxy clusters to slow down whereas the dark matter, which at best interacts only weakly with itself, continued on its original course. Thus, this object provides both confirmation of the existence of dark matter and a further understanding of its properties. This image is a composite of Hubble Space Telescope and Chandra X-ray Observatory data where dark matter is coloured blue (mapped by Hubble using gravitational lensing techniques) and ordinary matter is coloured pink (mapped by Chandra detecting X-rays from gas heated by the collision).