SkyEye

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

May 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	Tue
2	Wed	Full Moon
3	Thu	Mercury at superior conjunction
4	Fri	Moon occults first-magnitude star Antares: visible from southeastern Africa, Madagascar, Tasmania, New Zealand and the Antarctic.
5	Sat
6	Sun	The waning gibbous Moon greatly hinders viewing the Eta Aquariid meteor shower.
7	Mon
8	Tue
9	Wed	Saturn at east quadrature
10	Thu	Last Quarter Moon
11	Fri
12	Sat	Moon occults Uranus: visible from eastern Greenland, Iceland and most of the British Isles.
13	Sun	Neptune at west quadrature
14	Mon
15	Tue	Moon at perigee
16	Wed	New Moon
17	Thu
18	Fri
19	Sat
20	Sun
21	Mon
22	Tue	Moon occults Saturn: visible from northeastern Africa, northwestern Middle East, Europe, Russia, the Arctic and northwestern Canada.
23	Wed	First Quarter Moon occults first-magnitude star Regulus: visible from eastern Middle East, central Asia and India.
24	Thu
25	Fri
26	Sat
27	Sun	Moon at apogee
28	Mon
29	Tue
30	Wed	4 Vesta at opposition
31	Thu	The next Full Moon occurs at 0104 UT tomorrow. However, for time zones more than 2 hours behind Greenwich Mean Time (including the Americas and the eastern Pacific region), the Full Moon will occur today, making this a Blue Moon.

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: Aries -> Taurus
Mercury: Aries -> Taurus -> Gemini
The closest planet to the Sun is at superior conjunction on 3 May. It emerges from the solar glare into evening skies by mid-month and is best viewed from the northern hemisphere in the west after sunset.
Venus: Taurus -> Gemini
The brilliant "evening star" reaches its maximum altitude for northern hemisphere observers but the planet will continue to climb higher above the sunset horizon over the next few months for those viewing it from the southern hemisphere.
Mars: Aquarius -> Pisces -> Cetus -> Pisces
The brightening red planet rises in the early morning hours, finally pulling out of the dawn glare.
4 Vesta: Ophiuchus
Although not the biggest of the dwarf planets and small solar-system bodies, it is the brightest because of its high albedo. At opposition on the penultimate day of May, it reaches a naked-eye magnitude of +5.4. Look for it near the globular cluster M107.
Jupiter: Ophiuchus
The largest planet in the solar system is at opposition next month so it is visible most of the night. It rises earlier and earlier as May progresses.
Saturn: Leo
Quadrature is the best time to observe the planet through a telescope because the shadow cast by the planetary disc onto the rings is most pronounced. The rings are starting to close so don't delay in viewing this interesting event. Saturn is high above Venus in western skies at sunset and at the end of the month is setting by midnight.
Uranus: Aquarius
This distant gas giant is occulted by the Moon on 12 May. It rises about an hour after its neighbour Neptune.
Neptune: Capricornus
A small telescope is necessary to view the most distant planet in the solar system. Because it is at west quadrature on 13 May, it is almost exactly opposite from Saturn in the sky. (Saturn is at east quadrature four days earlier.) Thus, Neptune rises as Saturn sets.

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.