SkyEye

Welcome to SkyEye, your guide to this month's celestial events. All dates are based on Universal Time (UT).

The Sun and Moon

There are no eclipses this month. As seen from the Earth, the Sun is moving from the constellation Virgo to the constellation Libra.

The phases of the Moon are

Full : 5 October
Last Quarter : 12 October
New : 20 October
First Quarter : 28 October

The Full Moon nearest to the autumn equinox is sometimes referred to as the "Harvest Moon." Although this title usually goes to the Full Moon in September, this year October claims the prize. The Moon is at perigee on 6 October and at apogee on 21 October.

The Moon occults two bright planets, two minor planets, and two first-magnitude stars this month. At 6 UT on 4 October, tiny 2 Pallas slides behind the Moon's disk. This occurs during the hours of darkness in the North Pacific Ocean, Alaska, the Northwestern United States, and Canada where this event can be seen. Three hours later, Australia and the South Pacific Ocean can watch Jupiter disappear behind the limb of the Moon. Another double occultation occurs on 9 October when Aldebaran is occulted at 16 UT which is during the night in East China, Korea, Japan, and the North Pacific. Six hours later, Europe, North Asia, and the Arctic are treated to the sight of 1 Ceres disappearing behind the Moon. On 15 October, during daylight hours in the South Pacific Ocean and the southern parts of South America, Regulus is occulted by the Moon. The following day, in another daytime event, Mars disappears behind the Moon for observers in the South Indian Ocean and Antarctica. Finally, Jupiter is occulted once again on the last day of the month. This 17 UT event is visible during the hours of darkness in Madagascar, the Indian Ocean, Malaysia, and Indonesia.

The Planets

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. This chart shows the positions of the Sun and planets at mid-month.
Mercury
On 19 October, Mercury reaches aphelion, the closest point in its orbit around the Sun. Moving away from the Sun after last month's superior conjunction, Mercury can be seen very low in the western sky after sunset. This bright but elusive planet can be found moving from the constellation Virgo to Libra.
Venus
After a long run as the "morning star," Venus is too close to the Sun this month to be easily visible. In fact, this brightest of planets reaches superior conjunction on 30 October. Venus may be found with Mercury in the constellations of Virgo and Libra.
Mars
On 7 October, the red planet makes a striking spectacle with the bluish first magnitude star Regulus. Later in the month, on 16 October, Mars is occulted by the Moon during daylight hours. Mars is in the constellation Leo so it does not rise until after midnight.
Jupiter
Jupiter is occulted by the Moon twice this month. On 4 October, Australia and the South Pacific region will see Jupiter glide behind the disk of the Moon. Then, on the last day of the month, observers in Madagascar, the Indian Ocean, Malaysia, and Indonesia will see a second night-time occultation of the largest planet in the solar system. Jupiter is visible nearly all night in the constellation Aquarius.
Saturn
The ringed planet is up all night this month as it approaches opposition on 23 October. Look for it in the constellation Pisces.
Uranus
Uranus is just on the edge of naked-eye visibility and sets around midnight. It returns to prograde motion on 18 October. Visual aids will probably be needed it in the constellation Capricornus.
Neptune
Neptune is falling behind Uranus after their triple conjunction in 1993. Like Uranus, Neptune returns to prograde motion this month, this time on 11 October. On 23 October, the planet arrives at eastern quadrature. Only visible with a telescope, it can be found in the constellation Sagittarius before it sets around midnight.
Pluto
Pluto is currently closer to the Sun than Neptune but because it is so small and faint, a rather large telescope is always needed to see it. This smallest of the planets can be found in the constellation Ophiuchus, but you will need to look for it before mid-evening as it sets early.

Minor Planets, Comets and Meteors

Minor Planets
The Moon occults two minor planets in October. 2 Pallas is the first victim on 4 October and 1 Ceres succumbs to the same fate on 9 October. Look for 2 Pallas in the constellation of Aquarius and 1 Ceres in Taurus.
Comets
21P/Giacobini-Zinner was discovered late in the year 1900 by Giacobini in France. Missed in its 1907 return, Zinner in Germany rediscovered it in 1917. It was called Comet Zinner for a short time until it was realized that it was actually Comet Giacobini. This object is the parent comet of the Draconids meteor shower which peaks this month. As 21P/Giacobini-Zinner reaches perihelion on 21 November, this may mean a particularly fine meteor display.

A small comet, 21P/Giacobini-Zinner has a steeply inclined orbit (about 32°) and an eccentricity of 0.71. Its period is 6.6 years and its perihelion distance is just over 1 AU (or just outside the Earth's orbit. Visual aids will be needed to see this comet as it is expected to reach a maximum magnitude of only 9.

The comet's trajectory over the period October - December takes it through Ophiuchus, Serpens (Cauda), Aquila, Capricornus, and Aquarius. This chart shows the position of the comet every five days during this time period. The comet is travelling from west to east.

Meteors
There are two major meteor showers this month and one of them may well produce a spectacular display. The Draconids should reach their peak around 17 UT on 8 October. This shower can produce fine displays when its parent comet is near perihelion which will be the case next month. Although strong moonlight may interfere with viewing, the possibility of high meteor counts make this shower well worth observing. The best views will be in the far north where the radiant in Draco is circumpolar.

Later in the month, on 21 October, the Orionids will be at their best. Orion is more southerly so this shower can be observed by both hemispheres. The New Moon will give a fine dark sky as a backdrop for this shower.

The Celestial Sphere

Constellations are patterns of stars in the sky. The International Astronomical Union (IAU) recognizes 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 daylight savings time is in effect.

Northern Hemisphere : 45° N

Southern Hemisphere : 30° S

For More Information...

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 Sky & Telescope and in other fine amateur astronomy magazines 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 Sun in the SkyEye banner is courtesy of the SOHO/EIT consortium. SOHO is a project of international cooperation between ESA and NASA.

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