There is an annular-total eclipse of the sun visible from the Pacific Ocean and Central America on the 8th, the
Lyrids meteor shower on the 21st and 22nd and a full moon and a penumbral eclipse of the moon visible from the Pacific Ocean,
America, Australasia and Antarctica on the 24th.
The Lyrids Meteor Shower
The Lyrids meteor shower is associated with the comet Thatcher. Its radiant is found close to the
constellation of Lyra which lies between Cynus, sometimes called the Northern Cross, and Hercules.
The light from a nearly full moon will interfere with observing this year´s Lyrids. The shower lasts from 16th to 25th
April peaking on the morning of Friday 22nd. The moon will be low for an hour or so before morning twilight so that would be
the best period for observation.
Lyrid meteors travel quickly, faster than 49 km/s, which means they can be very bright. Lucky observers might see a Lyrid
fireball (a meteor brighter than Venus) which sometimes leave a lingering trail. The usual expectation would be to see
between 10-20 meteors per hour although in 1803 observers recorded more than 700 per hour.
The Lyrids are the oldest recorded meteor shower dating back some 2,600 years. Chinese records from 687BC describe
´´stars that fell like rain´´.
There are a few months to wait until the next major meteor shower which will be the Perseids in August.
||Mercury will not be observable again until June. The planet is at greatest
western elongation, 27 degrees, on the 26th April.
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.
||Until May, Venus 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.
||During April Mars moves from Capricorn into Aquarius and brightens to 0.6
magnitude, rising by 4.30h by the end of the month. The moon is below on the 4th and Neptune is close by on the 13th.
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 at -2.4 magnitude, is retrograde until opposition on the 3rd
April after which the planet resumes a direct motion moving eastwards against the stars. The planet sets about 6.00h by the
end of April with the moon closeby on the 22nd.
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 is at 0.2 magnitude in Gemini setting by 3.00h by the end of April with
the moon above on the 15th and 16th.
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 is in Aquarius rising by 5.00h by the end of April with the moon closeby
on the 5th.
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 is in Capricorn rising by 4.00h by the end of April with the moon
closeby on the 4th and Mars closeby on the 13th.
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: 2nd at 1.00h
New moon: 8th at 21.00h
First quarter: 16th at 15.00h
Full moon: 24th at 10.00h