SkyEye

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

July 2012

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	Sun	Mercury at greatest elongation east
1	Sun	Moon at perigee
2	Mon
3	Tue	Full Moon
4	Wed
5	Thu	Earth at aphelion
6	Fri
7	Sat
8	Sun
9	Mon
10	Tue
11	Wed	Last Quarter Moon
12	Thu
13	Fri	Moon at apogee
14	Sat	96P/Machholz 1 at perihelion
15	Sun	Moon occults Jupiter: visible from most of Europe, northeastern Africa, northern parts of the Arabian penninsula, the Middle East and northern Asia from about 01:50 UT.
15	Sun	Saturn at east quadrature
16	Mon
17	Tue
18	Wed
19	Thu	New Moon
20	Fri	Moon occults Mercury: visible from southern Africa, Madagascar and the southwestern tip of Australia from about 06:10 UT.
21	Sat
22	Sun
23	Mon
24	Tue
25	Wed	Moon occults Spica: visible from parts of Antarctica.
26	Thu	First Quarter Moon
27	Fri
28	Sat	Mercury at inferior conjunction
29	Sun	Proximity to next month's Full Moon makes observing the Delta Aquariids difficult except during the few hours between moonset and sunrise.
29	Sun	Moon at perigee
30	Mon
31	Tue

Coming up next month...

Curiosity, the latest Mars rover, is due to set down on the red planet on 6 August.

Moonlight should not interfere too much with the Perseids meteor shower on 12 August.

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
Earth reaches its farthest point from the Sun on 5 July. The date of aphelion can range from 2 July to 6 July.
96P/Machholz 1: Orion » Monoceros » Gemini » Cancer » Leo » Leo Minor » Leo
Predicted to be as bright as fourth magnitude when at perihelion in mid-July, this comet will probably dim quite rapidly as it races away from the Sun and may not be visible to the naked eye by the time it is far enough from our star to observe. It passes quite close to Wasat or delta Geminorum on 14 July.
Mercury: Cancer
Mercury is at greatest elongation east on the first day of the month and begins its descent back towards the western horizon. It is occulted by the Moon on 20 July and reaches inferior conjunction eight days later.
Venus: Taurus
After last month's spectacular transit, Venus now appears in the east before sunrise, taking on the role of 'morning star' and blazing away at an astounding -4.5 magnitude by mid-month. It rises quickly for those in the north but southern hemisphere observers see it climb in the sky more slowly.
Mars: Virgo
Look for the red planet in the west before it sets in late evening.
Jupiter: Taurus
This bright gas giant rises shortly in the early morning hours. It is occulted by the Moon on 15 July.
Saturn: Virgo
At east quadrature on 12 July, the ringed planet now sets before midnight. Look for it high in the west during evening hours. This is an excellent time to observe the interplay of shadows between the planet, its rings and its satellites.
Uranus: Cetus
This faint planet, on the edge of naked-eye visibility, rises late evening, just as Mars sets.
Neptune: Aquarius
A small telescope is necessary to view the most distant planet in the solar system. With opposition occurring next month, Neptune rises in the east shortly 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.

The SkyEye banner features the supernova remnant known as the Crab Nebula. Six light years wide and 6500 light years distant, this expanding nebula is the shattered remains of a star that blew up nearly a thousand years ago. At its heart beats a pulsar, a neutron star which spins at the incredible rate of 30 times per second. The supernova explosion which produced this object was observed in 1054 in China, Japan and Arabia. It was also seen in North America by the Anasazi people who lived in what is now New Mexico and who depicted it in a petroglpyh. This image is a composite assembled from 24 individual exposures taken by the Hubble Space Telescope in October 1999, January 2000 and December 2000, and is courtesy of NASA, ESA, Jeff Hester and Allison Loll (Arizona State University). The colours represent different elements which were expelled during the explosion: neutral oxygen (blue), doubly-ionised oxygen (red) and singly-ionised sulphur (green). These elements will find their way into the next generation of stars and planets (and extra-terrestrial life?).