SkyEye

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

August 2013

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	Thu
2	Fri
3	Sat	Moon at apogee
4	Sun
5	Mon
6	Tue	3 Juno at opposition
6	Tue	New Moon
7	Wed
8	Thu
9	Fri
10	Sat
11	Sun
12	Mon	The Moon occults first-magnitude star Spica: visible from the China and East Asia from about 07:15 UT.
12	Mon	The waxing crescent Moon should prove no obstacle to observing this year's Perseids (theoretical peak activity: about 18:00-21:00 UT).
13	Tue
14	Wed	First Quarter Moon
15	Thu
16	Fri
17	Sat
18	Sun
19	Mon	Moon at perigee
20	Tue
21	Wed	This Full Moon is a the third of four Full Moons this season, making it a traditional Blue Moon!
22	Thu
23	Fri
24	Sat	Mercury at superior conjunction
25	Sun
26	Mon
27	Tue	Neptune at opposition
28	Wed	Last Quarter Moon
29	Thu
30	Fri	Moon at apogee
31	Sat

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: Gemini » Cancer » Leo
Best seen in the east before sunrise at the beginning of the month, Mercury dives back towards the Sun, becoming lost in the solar glare by mid-month. It reaches superior conjunction on 24 August.
Venus: Leo » Virgo
The evening star never rises very high for northern hemisphere observers but continues to climb high in the west for those in the south.
Mars: Gemini » Cancer
The red planet rises ahead of the Sun but will not brighten to first-magnitude until much later this year.
3 Juno: Aquarius » Aquila
The third asteroid discovered will arrive at opposition on 6 August. A small telescope will be necessary to see this ninth-magnitude object.
Jupiter: Gemini
Bright Jupiter appears in the early morning hours, brightening imperceptively throughout the month.
Saturn: Virgo
Unlike its fellow gas giant, Saturn is an evening sky object and continues to put on a fine display in the west.
Uranus: Pisces
Uranus now rises before midnight.
Neptune: Aquarius
A small telescope is necessary to view the most distant planet in the solar system. Neptune is at opposition on 27 August but is eighth magnitude at best. It is, however, up all night so you'll have plenty of opportunities to look for it.

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 asteroid 243 Ida and its satellite Dactyl. On its way to Jupiter, the space probe Galileo passed by this asteroid on 28 August 1993 and took a series of pictures. The tiny object accompanying 243 Ida is Dactyl, a 'moon' of the asteroid, and the first confirmed satellite of an asteroid. This enhanced image (the true colour of the asteroid is mostly grey) is courtesy of the Jet Propulsion Laboratory.