SkyEye

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

January 2011

The Calendar

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	Sat
2	Sun	Conjunction of Jupiter and Uranus (last of the triple conjunction which began last year)
3	Mon	Earth at perihelion
4	Tue	Dark skies make this a perfect year for observing the northern hemisphere's Quadrantids (theoretical peak activity: from 01:00 UT but some computations suggest a peak sometime between 21:00 UT the previous evening and 06:00 UT).
		A partial solar eclipse is visible from northern Africa, Europe, the Middle East and central Asia.
		New Moon
5	Wed
6	Thu
7	Fri	Saturn at west quadrature
8	Sat	Venus at greatest elongation west
9	Sun	Mercury at greatest elongation west
10	Mon	Moon at apogee
11	Tue
12	Wed	First Quarter Moon
13	Thu
14	Fri
15	Sat
16	Sun
17	Mon
18	Tue
19	Wed	Full Moon
20	Thu
21	Fri
22	Sat	Moon at perigee
23	Sun
24	Mon
25	Tue
26	Wed	Last Quarter Moon
27	Thu
28	Fri
29	Sat
30	Sun
31	Mon

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. The following day, the Sun is partially eclipsed by the New Moon.
Mercury: Ophiuchus » Sagittarius
The closest planet to the Sun climbs out of the dawn glow this month, reaching greatest elongation west on 9 January. Early rising southern hemisphere observers will get the best views of this elusive planet. Look for it below the much brighter Venus.
Venus: Libra » Scorpius » Ophiuchus
The "morning star" is quite high in the east at the beginning of the month but is already heading back towards the horizon as seen from northern latitudes. Venus attains greatest elongation west a day before its inner solar system neighbour Mercury.
Mars: Sagittarius » Capricornus
The red planet sets just after the Sun as it heads towards conjunction early next month.
Jupiter: Pisces
Jupiter and Uranus began a triple conjunction last year on 6 June with a second meeting on 21 September. They meet for the third and final time on 2 January. Look for this pair in the west right after sunset as they set by mid-evening. Jupiter won't be difficult to spot; it's the brightest point of light in the sky!
Saturn: Virgo
Now rising before midnight, the ringed planet is best observed before dawn. With west quadrature occurring on 7 January, this is an excellent time to observe the interplay of shadows of the planet's disk, the planet's rings and the planet's satellites.
Uranus: Pisces
On 2 January, use the much brighter Jupiter to find faint Uranus less than a degree away to the north.
Neptune: Capricornus » Aquarius
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 easily 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.

The SkyEye banner features the beautiful planetary nebula NGC 2818. A planetary nebula is a glowing shell of gas surrounding a dying star. When a star begins to run out of fuel and expands into a red giant, the outer layers of the star are expelled into space, enriching the surrounding area with the heavy elements manufactured by the parent star. The remaining hot stellar core ionises the ejecta, causing it to glow for a few tens of thousands of years. Eventually the star fades away and nebula is no longer visible. This image was taken by the Hubble Space Telescope in November 2008 and is courtesy NASA, ESA, and the Hubble Heritage Team (STScI/AURA). The red colour represents nitrogen, green represents hydrogen and blue represents oxygen.