SkyEye

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

July 2007

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	Full Moon occurred yesterday at 1349 UT. However, for time zones more than 11 hours ahead of Greenwich Mean Time (including New Zealand and some south Pacific islands), this Full Moon occurs today, making the Full Moon at the end of the month a Blue Moon by the popular definition.
2	Mon
3	Tue
4	Wed
5	Thu
6	Fri	Earth at aphelion
7	Sat	Last Quarter Moon
8	Sun
9	Mon	Moon at perigee
10	Tue
11	Wed
12	Thu
13	Fri
14	Sat	New Moon
15	Sun
16	Mon	Moon occults Saturn: visible from western South America.
17	Tue	Moon occults first-magnitude star Regulus: visible from Indonesia and northern Australia.
18	Wed
19	Thu
20	Fri	Mercury at greatest elongation west
21	Sat
22	Sun	First Quarter Moon at apogee
23	Mon
24	Tue
25	Wed	Moon occults first-magnitude star Antares: visible from southern Africa, southeastern Australia and southern New Zealand.
26	Thu
27	Fri
28	Sat	Bright skies don't help viewing the Delta Aquariid meteor shower.
29	Sun
30	Mon	Full Moon
31	Tue	Moon occults Neptune: visible from the Antarctic.

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 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 6 July. The date of aphelion can range from 2 July to this date.
Mercury: Gemini -> Orion -> Gemini
Early this month the smallest planet in the solar system reappears in the morning sky. Greatest elongation west occurs on 20 July at which point Mercury begins its descent back towards the eastern horizon. It is very well placed for observing mid-month in both hemispheres.
Venus: Leo -> Sextans
The "evening star" is very close to Saturn on the first day of the month and shines a dazzling -4.5. It falls rapidly back towards the western horizon for observers in the northern hemisphere but stays well up in the sunset sky for those in the southern hemisphere wishing to catch a glimpse of our nearest planetary neighbour.
Mars: Aries -> Taurus
Now rising just after midnight, Mars continues to slowly brighten.
Jupiter: Ophiuchus
The largest planet in the solar system was at opposition last month so it is still well-placed for viewing during evening hours.
Saturn: Leo
Saturn is low in the west near Venus but is getting more difficult to see as the month progresses. It is occulted by the Moon on 16 July.
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. Occulted by the Moon on the last day of the 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 Hoag's Object in the SkyEye banner is courtesy of NASA and the Hubble Heritage Team (STScI/AURA). Discovered in 1950 by astronomer Art Hoag, this unusual ring galaxy is slightly larger than our own Milky Way. The blue ring is dominated by young, massive stars whilst the nucleus is comprised largely of older, yellower stars. Located 600 million light years away in the constellation of Serpens, Hoag's Object was photographed by the Hubble Space Telescope on 9 July 2001.