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June 2009: Solar Powered

June 2009

This month we bring the final interviews from JENAM, a round-up of current space missions, news about the anniversary of the 1919 eclipse, what you can see in the night sky, and the latest astronomy news.

The News

In the news this month:

The Variable Sun

Prof Mike Lockwood (University of Southampton) talks to us about the Sun. Mike starts by describing how the Sun's output waxes and wanes on an 11 year timescale. The cycle is related to the Sun's magnetic field and from sunspot records we know that this cycle is by far the normal behaviour of the Sun over the last few millenia. On top of the 11 year activity cycles there are longer cycles. The Sun's variability is seen in records of our climate and shows up in Grand Maxima, Minima and ice ages. Lower solar activity generally means lower average disruption to satellites and power systems and these should decline as we leave the current maxima. However, there is evidence that the biggest single outburst events occur at times of middling activity. The entire space age has occured within a grand maxima of solar activity - a cycle in the top 10% of activity - and we have never been a high-tech society in a time of middling activity before. The conversation ranges from global warming, to ESA's Ulysses and late nights in the library.

These are strange and exciting days for solar physicists.

Gamma ray astronomy

Neil interviewed Dr Jim Hinton (University of Leeds) about high energy astronomy. Most high-energy astronomy is done with satellite based detectors because the Earth's atmosphere is opaque to the gamma rays. From the ground it is possible to detect the cascade of particles produced by the high energy photon as it hits the atmosphere. This produces Cherenkov radiation which can then be detected by optical telescopes on the ground. Using telescopes such as AUGER and HESS, energetic sources such as supernova remnants, active galaxies, and nearby galaxies such as Centaurus A have been observed.

Mission Updates

JAXA's KAGUYA (SELENE) spacecraft has been orbiting the Moon since the end of 2007. The mission consists of a main orbiting satellite at about 100 km altitude and two small satellites (the Relay Satellite and VRAD Satellite) in a polar orbit. The mission has performed global mapping of the lunar surface, magnetic field measurements, and gravity field measurements. It has also sent back some brilliant HD movies from as low as 11 km above the lunar surface. The nominal mission came to an end in February 2009. Since then it has been working in an extended phase which will conclude when KAGUYA crashes into the Moon on June 10th 18:30 GMT. The impact will be on near side in "night-time area".

NASA's Mars Exploration Rover Spirit has far exceeded it's nominal lifetime of 90 days but is currently stuck in soft terrain on the west side of Home Plate. That hasn't stopped the plucky Spirit from taking lots of scientific measurements and panoramic pictures while it waits for the team on Earth to come up with a strategy to free it.

As Megan says in the news, Servicing Mission 4 to repair the Hubble Space Telescope has been a success. There is a great video filmed by astronauts inside Space Shuttle Atlantis as they release Hubble.

Anniversary of the 1919 Eclipse

In May 1919 Sir Arthur Eddington and the Royal Astronomical Society launched an historic expedition to observe a total solar eclipse. The idea was to test Einstein's Theory of Relativity by observing the light from background stars bent by the Sun during the 1919 eclipse. Researchers from the University of Oxford and the Royal Observatory Edinburgh have recreated the expedition and you can read about their trip on the 1919 eclipse blog.

The Night Sky

Ian Morison tells us what we can see in the night sky during June 2009.

Northern Hemisphere

June is not the best month to see the sky from the Northern Hemisphere as it doesn't get too dark. At around 11pm, overhead towards the north, is Ursa Major. There is more about Ursa Major on the night sky pages. Moving southwards you first cross the constellation of Hercules which has a 'keystone' of stars. Two-thirds of the up the right-hand side of the keystone, binoculars will show a slightly fuzzy blob. With a telescope you see the magnificent globular cluster M13. Below Hercules is the thirteenth constellation of the zodiac, the not particularly prominent Ophiuchus. To the right of Hercules is Corona Borealis - the Northern Crown. To the right of that is the constellation Bootes with one very nice bright star - Arcturus. Rising in the east towards the end of June we have Cygnus the Swan, Lyra, and Aquila the Eagle. The bright stars Deneb, Vega and Altair make up the Summer Triangle. With binoculars move from Altair a third of the way towards Vega. This part of the sky is called the Cygnus Rift and is a great cloud of dust. In front of that cloud we see Brocchi's Cluster or The Coathanger. Below Ophiuchus we have Scorpius and Sagittarius (containing the Teapot). From the northern latitudes of the UK we don't see these constellations well and a better view is seen from further south.

Jupiter, lying on the boundary of Aquarius and Capricornus, becomes more easily visible this month as its elevation in the pre-dawn sky is getting higher - about 24 degrees above the horizon by month's end. It rises at about 01:00 UT at the beginning of the month and 00:00 UT by the end of June. One problem with observing Jupiter with a telescope when it is so low in the sky is refraction in the atmosphere. This shifts the different colours of light in Jupiters image by differing amounts, so giving a blurred image. Using a green filter will help considerably in giving a cleaner image.

Saturn is seen as twilight deepens lying in Leo - but somewhat below the main body of the Lion. Its magnitude is +1 - not as bright as usual.

Mercury reaches "Western Elongation" on the 13th June which is when it lies furthest in angle from the Sun and seen before sunrise. However its elevation will be very low, and binoculars will almost certainly be needed to spot it (NB before the Sun rises!) at magnitude +0.6 given a very low north-eastern horizon. Warning: make sure that you are very careful to only observe before the Sun rises as seeing the Sun with binoculars is very dangerous.

Mars still remains low in the pre-dawn sky this month but, as it rises increasingly earlier than the Sun as the month progresses, will become easier to spot. It has a magnitude of +1.2.

Venus is now visible in the pre-dawn sky. It will only lie 14 degrees above the horizon as the Sun rises on the first of June, so will be easier to spot later in the month. It is at magnitude -4.2 at mid month, just to the lower right of Mars.

The highlights this month:

Southern Hemisphere

June is a great month to observe the night sky from the Southern Hemisphere. Towards the north you'll see Leo and Saturn above it. Towards the south is the most beautiful skyscape with the Milky Way arcing across the southern sky. Scorpius is above Sagittarius down in the south east. High up in the sky are Crux and Centaurus. Towards the south west is the beautiful region around Carina and Vela with the Eta Carina Nebula. Low in the south is the Small Magellanic Cloud and the Large Magellanic Cloud up and to the right.

Odds and Ends

Listener Kate MacLean and her daughter have started a Facebook group called Shine Down! to raise awareness about full cut-off lighting.

Several Jodcast listeners have been inspired to create episodes for the 365 Days of Astronomy podcast. RapidEye has created episodes about M3, Wolf Rayet stars and January's garnet star. Nik Whitehead has created a great episode all about the life of a proton.

On the Forum a list of astronomical abbreviations has been started by Jodatheoak, RapidEye, EarthUnit and leloup.

Finally, check out the Sixty Symbols videos (technically not a podcast as the videos are not included in the RSS feed) from the University of Nottingham.

Show Credits

News:Megan Argo
Noticias en Español - Junio 2009:Lizette Ramirez
Interview:Prof Mike Lockwood, Michael Bareford, Kerry Hebdon and Neil Young
Interview:Dr Jim Hinton and Neil Young
Night sky this month:Ian Morison
Presenters:David Ault, Jen Gupta and Stuart Lowe
Editors:Stuart Lowe and Sam Bates
Intro script:David Ault (and William Shakespeare)
Segment voice:Danny Wong-McSweeney
Website:Stuart Lowe
Cover art:Part of active region 9169 Credit: SOHO/NASA/ESA

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