SkyEye

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

August 2012

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	Wed
2	Thu	Full Moon
3	Fri
4	Sat
5	Sun
6	Mon	The Curiosity rover is due to land on Mars.
7	Tue
8	Wed
9	Thu	Last Quarter Moon
10	Fri	Moon at apogee
11	Sat	Moon occults Jupiter: visible from parts of Indonesia from about 18:45 UT.
12	Sun	The waning cresent Moon is a bit of nuisance during this year's Perseids (theoretical peak activity: between 12:00 UT and 14:30 UT).
13	Mon	Moon occults Venus: visible from northeastern Asia and most of North America from about 17:40 UT.
14	Tue
15	Wed	Venus at greatest elongation west
16	Thu	Mercury at greatest elongation west
17	Fri	New Moon
18	Sat
19	Sun
20	Mon
21	Tue	Moon occults Spica: visible from Australia and New Zealand from about 22:00 UT.
22	Wed
23	Thu	Moon at perigee
24	Fri	Neptune at opposition
24	Fri	First Quarter Moon
25	Sat	Neil A. Armstrong, first human being to walk on the Moon, has died.
26	Sun
27	Mon
28	Tue
29	Wed
30	Thu
31	Fri	The second Full Moon this calendar month is popularly called a Blue Moon. It completely obliterates observations of the Alpha Aurigids.

Coming up next month...

Earth's equinox and the Harvest Moon occur late in September.

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: Cancer » Leo
Mercury: Cancer » Leo
This tiny planet is at greatest elongation west just a day after its neighbour Venus. Look for it in the east before sunrise.
Venus: Taurus » Orion » Gemini
The 'morning star' is very high for northern viewers and continues to climb above the horison in the eastern sky before sunrise. For those in southern latitudes, the bright planet is not as high in the sky and is already starting to descend back towards the horizon. Venus is occulted by the Moon on 13 August and reaches greatest elongation west two days later.
Mars: Virgo
The red planet receives another visitor from Earth this month when the Curiosity rover sets down on 6 August. At mid-month, Mars will pass between the planet Saturn and the first-magnitude star Spica.
Jupiter: Taurus
The largest planet in the solar system disappears behind the disc of the Moon on 11 August. Jupiter rises around midnight.
Saturn: Virgo
Now setting in mid-evening, the ringed planet has a close encounter with Mars in the middle of the month.
Uranus: Cetus
With opposition approaching next month, Uranus is up nearly all night, rising in the early evening.
Neptune: Aquarius
A small telescope is necessary to view the most distant planet in the solar system. Neptune is at opposition on 24 August but is eighth magnitude at best.

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 supernova remnant known as the Crab Nebula. Six light years wide and 6500 light years distant, this expanding nebula is the shattered remains of a star that blew up nearly a thousand years ago. At its heart beats a pulsar, a neutron star which spins at the incredible rate of 30 times per second. The supernova explosion which produced this object was observed in 1054 in China, Japan and Arabia. It was also seen in North America by the Anasazi people who lived in what is now New Mexico and who depicted it in a petroglpyh. This image is a composite assembled from 24 individual exposures taken by the Hubble Space Telescope in October 1999, January 2000 and December 2000, and is courtesy of NASA, ESA, Jeff Hester and Allison Loll (Arizona State University). The colours represent different elements which were expelled during the explosion: neutral oxygen (blue), doubly-ionised oxygen (red) and singly-ionised sulphur (green). These elements will find their way into the next generation of stars and planets (and extra-terrestrial life?).