SkyEye

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

August 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	Sun
2	Mon
3	Tue	Last Quarter Moon
4	Wed	Moon occults the Pleiades: visible from around 14:20 UT in New Zealand and the nearby islands to the north and east.
5	Thu
6	Fri
7	Sat	Mercury at greatest elongation east
8	Sun
9	Mon
10	Tue	New Moon at perigee: expect high tides since perigee occurs less than fifteen hours after the new phase.
11	Wed
12	Thu	Perfect skies greet this year's arrival of the famous Perseids (theoretical peak activity: from 23:30 UT and continuing into the early morning hours).
13	Fri
14	Sat
15	Sun
16	Mon	First Quarter Moon
17	Tue
18	Wed
19	Thu
20	Fri	Venus at greatest elongation east
20	Fri	Neptune at opposition
21	Sat
22	Sun
23	Mon
24	Tue	Full Moon
25	Wed	Apogee
26	Thu
27	Fri
28	Sat
29	Sun
30	Mon
31	Tue	Moon occults the Pleiades: visible from around 22:10 UT in southern Africa, Madagascar and Mauritius.

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: Leo
After greatest elongation east on 7 August, Mercury rapidly descends toward the horizon as seen from southern latitudes. This elusive planet is always low in the western sky for northern hemisphere observers.
Venus: Leo » Virgo
The "evening star" appears twice as high above the western horizon when viewed from the southern hemisphere as from the north. It reaches greatest elongation east on 20 August.
Mars: Virgo
The red planet is slowly dropping into the evening twilight.
Jupiter: Pisces
The largest planet in the solar system rises earlier every evening.
Saturn: Virgo
Look for the ringed planet in the west after sunset.
Uranus: Pisces
With opposition approaching next month, Uranus is up nearly all night.
Neptune: Aquarius » Capricornus
A small telescope is necessary to view the most distant planet in the solar system. Neptune is at opposition on 20 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 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).