SkyEye

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

April 2009

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	Wed
2	Thu	First Quarter Moon at perigee
3	Fri
4	Sat
5	Sun
6	Mon
7	Tue
8	Wed
9	Thu	Full Moon
10	Fri
11	Sat
12	Sun
13	Mon	Moon occults Antares: visible from about 1100 UT in the equatorial Pacific Ocean region.
14	Tue
15	Wed
16	Thu	Moon at apogee
17	Fri	Last Quarter Moon
18	Sat
19	Sun
20	Mon
21	Tue
22	Wed	Dark skies greet this year's Lyrids.
22	Wed	Moon occults Venus: visible from about 1200 UT from western North America.
23	Thu	The Pi Puppids are similarly graced with very dark skies.
24	Fri
25	Sat	New Moon
26	Sun	Mercury at greatest elongation east
27	Mon
28	Tue	Moon at perigee
29	Wed
30	Thu	Moon occults the Pleiades: visible from about 2100 UT in Portugal.

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: Pisces -> Aries
Mercury: Pisces -> Aries -> Taurus
The low "evening star" is best seen in the west from the northern hemisphere. At greatest elongation east on 26 April, this tiny planet can be found near the Pleiades at the end of the month.
Venus: Pisces
Last month, the northern hemisphere had the best views of Venus. As it passed north of the Sun's disc late last month, observers from northern latitudes were able to see our nearest neighbour both in the evening and in the morning. This month it rises slowly above the horizon in the morning sky. However, southern hemisphere views of the "morning star" are much more favourable, with Venus climbing rapidly above the eastern horizon.
Mars: Aquarius -> Pisces
Mars, glowing red in the morning twilight, rises not much before the Sun.
Jupiter: Capricornus
The largest planet in the solar system now rises well ahead of the Sun. The most distant planet in the solar system, Neptune, is nearby in the sky.
Saturn: Leo
Opposition happened only last month so the ringed planet can be seen up most of the night.
Uranus: Pisces
With conjunction only last month, this distant gas giant is probably still lost in the glare of the rising Sun. The much brighter red "star" nearby is Mars.
Neptune: Capricornus
A small telescope is necessary to view the most distant planet in the solar system. It rises about an hour before its outer solar system neighbour Uranus.

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 SkyEye banner features a view of Saturn from its satellite Iapetus and is courtesy of NASA/JPL/Space Science Institute. Of all the major satellites of Saturn, Iapetus is the only one with a significant orbital inclination. Thus, whilst the rings appear nearly edge-on from all of the other major satellites, from Iapetus they are usually seen at a tilt. This image was taken during the Cassini-Huygens mission on 10 September 2007 and consists of 15 red, green and blue spectral filter images.