SkyEye

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

October 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	Mon
2	Tue
3	Wed	Last Quarter Moon
4	Thu
5	Fri
6	Sat
7	Sun	Moon occults first-magnitude star Regulus: visible from the north Atlantic, western Europe and northwestern Africa.
7	Sun	Moon occults Saturn: visible from the south Pacific.
8	Mon
9	Tue	Nearly ideal observing conditions greet this year's Draconid meteor shower.
10	Wed
11	Thu	New Moon
12	Fri
13	Sat	Moon at apogee
14	Sun
15	Mon
16	Tue
17	Wed
18	Thu
19	Fri	First Quarter Moon
20	Sat
21	Sun	Although the waxing gibbous Moon interferes with the Orionid meteor shower early in the night, the skies are dark later.
22	Mon
23	Tue	Mercury at inferior conjunction
24	Wed	Comet 17P/Holmes undergoes huge outburst in brightness
25	Thu
26	Fri	Full Moon at perigee: expect unusually high tides.
27	Sat
28	Sun	Venus at greatest elongation west
28	Sun	Comet C/2007 F1 (LONEOS) at perihelion
29	Mon
30	Tue
31	Wed	A cross-quarter day occurs midway between equinoxes and solstices.

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 like comets are not so constrained, often moving far above or below the ecliptic.

Sun: Virgo -> Libra
Comet 17P/Holmes: Perseus
Normally invisible to the naked eye, Comet 17P/Holmes unexpectedly became many magnitudes brighter on 24 October, reaching third magnitude. Discovered by London observer Edwin Holmes on 6 November 1892, the comet has a period of approximately 7 years and spends its time between the orbits of Mars and Jupiter, last reaching perihelion in May this year. To find the comet, look for an "extra" third-magnitude "star" near delta Persei.
Comet C/2007 F1 LONEOS: Coma Berenices -> Boötes -> Virgo -> Serpens (Caput) -> Libra
Discovered on 19 March 2007 as part of the Lowell Observatory Near-Earth-Object Search (LONEOS), this hyperbolic comet may brighten to fifth magnitude by the time it reaches perihelion near the end of the month. For northern hemisphere observers, it is best seen low above the western horizon after sunset and but also can be observed until mid-month just above the eastern horizon. It is heading southwards in the sky and will be visible to southern hemisphere comet chasers next month.
Mercury: Virgo
Always near the western horizon when seen from the northern hemisphere, this elusive planet disappears mid-month as it heads for inferior conjunction on 23 October. Southern hemisphere observers get a better view early in October but Mercury dives for the horizon, not to reappear (in the morning sky) until next month.
Venus: Leo
Venus, Saturn and the first-magnitude star Regulus appear very close together early in the month and have their tightest grouping on 10 October. Venus is at greatest elongation west on 28 October. It continues to rise higher in the dawn sky for northern hemisphere observers but stays mostly level when seen from the south.
Mars: Gemini
The red planet is passing through our galaxy, the Milky Way, this month and passes several open clusters, including M35 on 4 October. It rises mid-evening.
Jupiter: Ophiuchus
The "evening star" sets early in the evening.
Saturn: Leo
The ringed planet rises early in the morning. It appears very close together with Venus and the first-magnitude star Regulus throughout the month but particularly on 10 October. Three days earlier, the Moon joins this gathering, occulting Saturn.
Uranus: Aquarius
At opposition last month, this green-coloured gas giant sets before dawn.
Neptune: Capricornus
A small telescope is necessary to view the most distant planet in the solar system which sets just after midnight.

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.