SkyEye

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

January 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	Perigee
2	Sat
3	Sun	Perihelion
3	Sun	The waning gibbous Moon washes out the Quadrantids (theoretical peak activity: from 19:00 UT but possibly a brief maximum three to six hours earlier).
4	Mon	Mercury at inferior conjunction
5	Tue
6	Wed
7	Thu	Last Quarter Moon
8	Fri
9	Sat
10	Sun
11	Mon	Moon occults Antares: visible from about 12:00 UT in northeastern Canada and the southernmost tip of Greenland.
11	Mon	Venus at superior conjunction
12	Tue
13	Wed
14	Thu
15	Fri	An annular solar eclipse is visible from parts of Africa, the Indian Ocean and China. Because the Earth is near perihelion, the solar disk appears slightly larger than average. The Moon, however, is near apogee, so the lunar disk appears slightly smaller than average. This combination of events means that this eclipse is unusually long. A longer annular solar eclipse won't take place again until the third millenium.
15	Fri	New Moon
16	Sat
17	Sun	Apogee
18	Mon
19	Tue
20	Wed
21	Thu
22	Fri
23	Sat	First Quarter Moon
24	Sun
25	Mon	Moon occults the Pleiades: visible from around 09:30 UT in eastern Russia, northeastern China, Taiwan, Korea, Japan, Hawaii, the northern tip of Australia, Indonesia, New Guinea and other central Pacific islands.
26	Tue
27	Wed	Mercury at greatest elongation west
28	Thu
29	Fri	Mars at opposition
30	Sat	Full Moon at perigee: expect particularly high tides since perigee occurs less than three hours after the full phase. Because this is the closest perigee of the year, the Moon appears at its largest. For parts of the world five or more hours ahead (east) of Greenwich, this is a blue moon, by modern definition the second Full Moon 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: Sagittarius » Capricornus
The Earth makes its annual closest approach to the Sun on 3 January. The date of perihelion can range from New Year's Day to 4 January.
Mercury: Sagittarius
Southern hemisphere observers get the best view of this morning sky object. Too close to the Sun to see early in the month (this tiny planet is at inferior conjuntion on 4 January), it climbs into the eastern or southeastern sky before sunrise, reaching greatest elongation west on 27 January.
Venus: Sagittarius » Capricornus
Last month's "morning star" disappears from view as it undergoes superior conjunction on 11 January. It reappears very low in the west just after sunset at the end of the month.
Mars: Cancer
At opposition on 29 January, the red planet is at its biggest and brightest, and is visible all night. Mars has its closest approach to Earth two days before opposition.
Jupiter: Capricornus » Aquarius
The "evening star" sets earlier every evening. Look for it low in the west after sunset.
Saturn: Virgo
The rings are widening slightly after last year's ring plane crossing event. Saturn rises before midnight and is at it highest in the sky in the early hours before sunrise.
Uranus: Aquarius » Pisces
The most distant of the naked-eye planets undergoes conjunction in March so it is getting difficult to see in the western sky, setting by mid-evening.
Neptune: Capricornus
A small telescope is necessary to view the most distant planet in the solar system. However, with conjunction approaching next month, it is probably too close to the Sun to observe.

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).