|Special Events in October
During October 2005, Mars is stationary on the 1st, there is a full moon on the 17th, the Orionids meteor
shower lasts from the 20th to the 22nd, Jupiter is conjunct with the sun on the 22nd and Neptune is stationary on the 26th.
On the 3rd October there will be an Annular Eclipse of the Sun. This annular eclipse will be visible from
within a narrow corridor traversing the Iberian Peninsula and stretching across the African continent. A partial eclipse
will be seen within the much broader path of the Moon's penumbral shadow, which includes Europe, western Asia, the Middle
East, India and most of Africa.
The path of the annular eclipse begins in the North Atlantic at 08:41 UT. Quickly moving southeast, the penumbra reaches
the northern coast of Spain and Portugal at 10.51h (08:51 UT). Bisecting the Iberian Peninsula, the penumbra engulfs Madrid
at 08:56 UT which lies near the central line. The annular phase will last 4m 11s from this capital city with 90% of the
Sun's surface being obscured by the Moon. Ibiza straddles the northern path limit as the shadow crosses the western
Mediterranean. Upon reaching the African continent, Algiers lies within the shadow's trajectory at 09:05 UT and will
experience an annularity of 3m 51s. Following a south eastern course, the penumbra passes through southern Tunisia and
central Libya where the Moon's umbral shadow will return six months later during the total eclipse of 2006 Mar 29. After
briefly skirting northern Chad, the penumbra sweeps across central Sudan where greatest eclipse occurs at 10:31:42 UT with
annular duration of 4m 31s. The central track runs along the southern Sudanese-Ethiopian border before entering northern
Kenya where it engulfs much of Lake Rudolf at 11:10 UT. Southernmost Somalia is the penumbra's final landfall at 11:30 UT
before heading east across the Indian Ocean where the path ends at local sunset, 12:22 UT.
On the 17th October there will be a Partial Eclipse of the Moon. In a partial eclipse only part of the Moon passes through
the Earth's dark umbral shadow, the rest through the lighter penumbra. During this eclipse only the extreme southern part of
the Moon will pass through the umbra. Visible from the Pacific Ocean, Arctic Ocean, East Asia, Indonesia and Australia.
The Orionids meteor shower lasts from the 15th to the 29th October with maximum meteors occurring from the 20th -22nd.
With a full moon on the 17th October this year, lunar light will affect visibility and cause unfavourable observational
conditions. But, whether enjoying quiet outdoor contemplation or a rawdy barbeque, these meteors are still very much worth
looking out for.
||Mercury is an evening object setting too soon after the sun for observation.
The best times to observe Mercury are when it is an evening star in the spring and a morning star in the autumn. In midsummer the lighter skies make visibility difficult near the horizon.
||Heading for maximum brilliance this year, Venus is at –4.4 magnitude setting
two hours after the sun by the end of October. Visible in low western twilight with the moon closeby on the 6th to 7th.
On the 8th June 2004, Venus was at inferior conjunction and transited the sun. Transits of Venus are rare, taking place at greater
than 100 year intervals and usually in pairs. The last two transits of Venus were in 1874 and 1882. June's transit
began at 7.20h and lasted 6 hours until 13.20h, the total event visible from Europe as a small black disc crossing
the lower part of the sun from left to right. The next transit will be in late June 2012. After that, transits of Venus
won't occur again until 2117 and 2125.
Before and after inferior conjuction, when Venus is
the closest it comes to the earth, are the times at which the planet is most brilliant and can be seen setting or rising
4 hours after or before the sun. The dates of the next two inferior conjunctions are October 28th 2010 and October 26th 2018.
||Mars, remaining in Aries since July, brightens to –2.2 magnitude and rises
about sunset by the end of October. Mars is stationary on the 1st.
At opposition on the 28th August 2003, Mars was only 56 million kilometres from the earth. It showed a
disc of 25.1 seconds of arc across which is almost as large as it can ever appear. Mars started 2003 at 310 million kilometres from
the earth at 4.5 seconds of arc and 1.6 magnitude. By opposition it brightened 50 times to reach -2.9 magnitude but faded to 0
magnitude by December. Even to the naked eye Mars was a striking object in the summer and autumn sky, easily identifiable by its
reddish hue in an area of sky poor in bright stars. Mars will not be as close again for another 15 years.
These favourable oppositions occur every 15 years but other oppositions occur at average intervals of 2 years 2 months. In general Mars is observable every other year, being too close to the sun for favourable conditions during other times. Brightness at opposition varies from -1.0 to -2.9 magnitude, and when furthest from the earth it fades to 1.7 magnitude. The planet can be identified by its orange-red colour.
||Jupiter, in Virgo throughout 2005, is in conjunction with the sun on the 22nd
October and is therefore not observable this month.
Being 770 million kilometres from the sun, the difference in brightness between opposition and conjunction varies less than with Mars, from about -2.8 to -1.8 magnitude.
The 4 largest moons of Jupiter are easily visible through a small telescope, ranging from 4.6 to 5.6 in magnitude. The innermost, Io, takes 1.8 days to orbit the planet making its motion easily detectable within a few minutes.
||Saturn, in Cancer since June until the end of 2005, is 0.3 magnitude rising
about 23.30h by Halloween. The moon is closeby on the 25th October.
Saturn crossed the equator into the northern hemisphere in 1996 where it will remain until 2010 with the southern side of the ring system facing the earth. Because of its distance, its brightness varies little between opposition and conjunction but is affected by the huge ring system. Seen edge on the rings contribute little or no light.
Every 15 years the plane of Saturn's rings passes through the sun, illuminating first the north and then the south side. For a few days the rings are edge on to the sun. About the same time the earth passes through the ring plane and, depending on the earth's position this may happen just once or 3 times. During 1995/96 there was a triple crossing and the next will be 2038/39. The next single crossings will be in 2009 and 2025.
Saturn's largest moon, Titan, is visible in small telescopes orbiting outside of the ring system.
||Uranus, in Aquarius throughout 2005, sets about 2.00h by the end of October.
The moon is closeby on the 13th.
Brightness varies slightly reaching 5.6 magnitude at opposition. This is bright enough to see with the naked eye but identifying it against the stars is difficult.
||Neptune, in Capricorn throughout 2005, sets about midnight by Halloween. It is
stationary on the 26th October with the moon closeby on the 12th.
Neptune has an average magnitude of 7.9 which varies little with changing distance.
||Never brighter than 13 magnitude, Pluto is only visible through powerful telescopes and we will therefore not be reporting on its position in the sky.|
||New moon: 3rd at 10.00h
First quarter: 10th at 19.00h
Full moon: 17th at 12.00h
Last quarter: 25th at 01.00h