SkyEye

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

July 2008

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	Tue	Mercury at greatest elongation west
1	Tue	Moon at perigee
2	Wed
3	Thu	New Moon
4	Fri	Earth at aphelion
5	Sat
6	Sun
7	Mon
8	Tue
9	Wed	Jupiter at opposition
10	Thu	First Quarter Moon
11	Fri
12	Sat
13	Sun
14	Mon	Moon at apogee
14	Mon	Moon occults first-magnitude star Antares: visible from southern Australia and New Zealand from about 11:00 UT.
15	Tue
16	Wed
17	Thu
18	Fri	Full Moon
19	Sat
20	Sun
21	Mon
22	Tue
23	Wed
24	Thu
25	Fri	Last Quarter Moon
26	Sat
27	Sun	Dark skies favour this year's appearance of the Delta Aquariid meteor shower.
28	Mon
29	Tue	Mercury at superior conjunction
29	Tue	Moon at perigee
30	Wed
31	Thu

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: Gemini -> Cancer
The Earth reaches its farthest point from the Sun on 4 July. The date of aphelion can range from 2 July to 6 July.
Mercury: Taurus -> Gemini -> Cancer
The smallest planet in the solar system is very well placed for observing early in the month from both hemispheres before descending towards the rising Sun. It disappears from the morning sky late in the month and reaches superior conjunction on 29 July.
Venus: Gemini -> Cancer -> Leo
The "evening star" is quite close to the horizon for northern hemisphere observers and is not much higher when seen from the southern half of our planet. Venus will remain rather low for most of the year but is best viewed from the southern hemisphere. Look for our nearest neighbour to pass in front of the open star cluster M44, the Beehive Cluster, on 18 July.
Mars: Leo
The red planet makes it closest approach to the first-magnitude star Regulus on the first day of the month and appears near Saturn on 10 July. Look for all three bright objects in the west after sunset.
Jupiter: Sagittarius
The largest planet in the solar system is at opposition on 9 July so it is at its biggest and brightest (nearly -3 magnitude) and is up all night.
Saturn: Leo
Saturn is low in the west near Mars but is getting more difficult to see as the month progresses. The two planets appear in a tight group with Regulus early in the month.
Uranus: Aquarius
Uranus rises an hour after its neighbour Neptune.
Neptune: Capricornus
A small telescope is necessary to view the most distant planet in the solar system. With opposition occuring next month, Neptune rises just after sunset.

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 image of the variable star V838 Monocerotis in the SkyEye banner is courtesy of NASA, ESA and the Hubble Heritage Team (STScI/AURA). Located 20,000 light years away in the constellation of Monoceros, V838 Mon temporarily brightened in early 2002. The reason for this outburst is not understood. The resulting light echo, the light from the stellar explosion illuminating the dust surrounding the the star, was captured by the Hubble Space Telescope in October of that year.