The US Space Shuttle & The International Space Station
Two years ago the Columbia disaster grounded the American space shuttle program and brought the assembly of the
half-built International Space Shuttle (ISS) to a near standstill.
Currently the three-man Russian Soyuz spacecraft ferries astronauts to and from the space station but finishing the ISS
is dependent on the US shuttle. During the last two years the shuttle has undergone expensive modifications and is due for
test flights this May and June. Although a sequence of shuttle flights and ISS component consignments for finishing the ISS
have been scheduled, the actual dates will depend upon results of the shuttle test flights. In January this year a
consortium of five international partners from Europe, the US, Canada, Russia and Japan responsible for managing, building
and operating the ISS met to discuss its future. The end of the decade was set as a deadline for completion of the ISS.
The Spring Equinox is on the 20th and there is a full moon on the 25th.
||During March Mercury fades from –1.2 to 0 magnitude. The planet is at
greatest elongation, 18 degrees, on the 12th and at inferior conjunction on the 29th. Mercury can be observed low in the
western sky 1 hour after sunset until the 12th, after which it will not be observable again until June. The moon is closeby
on the 11th.
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.
||Venus is at superior conjunction on the 31st and until May
is too close to the sun to be observable.
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 moves from Sagittarius into Capricorn late in March. Still brightening Mars reaches 0.9 magnitude and rises by
6.00h by the end of the month. The moon is closeby on the 6th.
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 is retrograde moving westwards against the stars and remaining in Virgo
throughout 2005. During March Jupiter is -2.5 magnitude, the brightest the planet will be this year. Rising at sunset by
the end of the month with the moon closeby on the 26th.
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.
||During March Saturn continues a retrograde path in Gemini until stationary on the 22nd after which it
resumes direct motion moving eastwards against the stars. At 0.1 magnitude, Saturn sets about 5.00h by the end of the month.
The moon is above on the 19th.
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 remains in Aquarius throughout 2005 and rises by 6.30h by the end of
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 remains in Capricorn throughout 2005
and rises by 6.00h by the end of March.
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.|
||Last quarter: 3rd at 19.00h
New moon: 10th at 10.00h
First quarter: 17th at 20.00h
Full moon: 25th at 22.00h