With phones now taking on more and more of the duties usually associated with fully-fledged computers, phone ‘apps’ have become genuinely useful aids for a variety of activities including astronomy. In this blog piece I’ve highlighted three applications for Google Android devices that have great content and prove to be a great help, whether you are observing with the unaided eye or with a telescope. Also, there are many fantastic astronomy applications for other phones. Feel free to add any of your own suggestions in the comments below – our team here at the Royal Observatory Greenwich will also be contributing. Enjoy!
Google Sky Map
Price: FREE
By far the most popular Android astronomy application, Google Sky Map provides a virtual window to peer into space. If your phone has a built-in compass, the application can display the sky wherever you point your phone! Sky Map also has a manual mode to drag your finger across the sky. Stars, constellations, deep sky objects, planets and the Moon are all displayed for your current time and location. Recently, the “Time Travel” feature has been added to see what the sky looks like for any time in the past or in the future. If you’re looking for something in particular such as a planet or galaxy, you can search for it, and a pointer interface will guide you to your target.
Moon Widget
Price: FREE
This no frills app gives you the most important information about the Moon at a glance. Adding this widget to your phone will give you a discrete image of the current phase of the Moon and times for Moonrise and Moonset. Having an application like this helps plan for a nights observations. If the Moon is coming up to, or is in, its full moon phase, then waiting until moonset comes highly recommended. By tapping into the Moon Widget some more detail is given about the Moon’s current location, distance and how many days into the lunar cycle it is. As a preparation before a night of stargazing, this is a great addition to your app collection.
WhereIsIt
Price: $0.99
Just as we use longitude and latitude to mark our location here on Earth, there are equivalents for the night sky so that astronomers around the world can find their chosen target. The coordinates are called Declination (Dec) and Right Ascension (RA), but to make them useful for observing, some calculations are required. WhereIsIt makes the whole process pain-free by taking your current location and time, and converting Dec and RA to altitude and azimuth. Altitude tells you how far up from the horizon you should be looking or pointing your telescope. Azimuth tells you how many degrees (clockwise) around from North to look or aim. If you have the coordinates for your target, you can manually input them or you can select from a list of bright celestial objects including stars, galaxies and nebulae.
There are many more Android astronomy applications that could be mentioned in more detail here, but just try searching for “Astronomy” in the Market and see what you can find! For reviews of some of the top iPhone astronomy apps, check out this month’s edition of the Sky at Night magazine and don’t hesitate to contribute to the comments section below! Also, check out the Royal Observatory Greenwich facebook page here for the latest info on events and astronomy news!
26 November 2010 – NASA’s Cassini probe has scooped oxygen from the atmosphere of Saturn’s second largest moon, the icy Rhea. This is the first time the gas has been directly seen in the atmosphere of another world, though scientists have previously used telescopes to detect oxygen on other moons and planets, including Jupiter’s moons Europa and Ganymede.
In a flyby in March, Cassini’s instruments found an extremely thin atmosphere – or strictly exosphere – with tiny concentrations of oxygen and carbon dioxide. At a peak density of around 20 billion molecules per cubic metre, the density of oxygen in Rhea’s exosphere is about 5 million million times lower than that found in Earth’s atmosphere.
Rhea’s exosphere is maintained by a constant stream of high-energy particles bombarding the moon’s icy surface, breaking water molecules and forming oxygen. The carbon dioxide may also be produced by particle impacts, or could come from dry ice trapped within the moon or from carbon-rich meteor deposits.
Team leader Dr Ben Teolis believes that there could be billions of similar exospheres throughout the galaxy. One strong candidate is Saturn’s moons Tethys, which Cassini is due to fly by in December 2011.
The Cassini mission is a joint project of NASA, the European Space Agency (ESA) and the Italian Space Agency (ASI). Cassini arrived at Saturn in 2004 after a seven-year voyage across billions of kilometres of space, and its mission has been extended until 2017 when it will destroy itself by plunging into Saturn’s atmosphere.
See a selection of beautiful images from the Cassini-Huygens mission in our Visions of Saturn pages.
19 Novmber 2010 – Over the past 15 years scientists have found nearly 500 planets outside our solar system, but till now all of these have been within our galaxy – the sheer distances involved preclude detection of planets outside the Milky Way. But now astronomers have identified a planet orbiting a star that originally belonged to a separate dwarf galaxy, one which was swallowed up by the Milky Way some 6 to 9 billion years ago.
The new-found planet HIP13044b is about 2000 light years from Earth, is at least 1.25 times more massive than Jupiter, and orbits close to its star with an orbital period (year) of just 16.2 days. Researchers say the planet would have been formed in its solar system’s early days, prior to incorporation into the Milky Way.
The planet’s star HIP13044 (appearing in the southern constellation Fornax) has passed its red giant phase and is nearing the end of its life, so it offers an intriguing glimpse into what the last years of our own Solar System may look like. The star is rotating relatively fast, which may be a result of swallowing its nearest planets during the red giant phase. One remaining puzzle is that the star does not appear to contain the heavy elements which are usually thought to be needed for planet formation.
Researchers discovered the planet using the ‘radial velocity method’, using a telescope-connected spectrograph at the ESO’s La Silla facility to detect the small wobbles in a star caused by an orbiting planet’s gravitational pull.
Hayabusa probe brought back asteroid dust from Itokawa
16 November 2010 – After five months of testing, Japanese scientists have confirmed that particles brought back by the Hayabusa probe in June this year are indeed from the 300 million km-distant asteroid 25143 Itokawa. This is the first time asteroid samples have been brought back to Earth, and only the fourth set of extra-terrestrial samples returned by spacecraft.
The Hayabusa space probe spent three weeks in orbit round the 500m-long asteroid in 2005. Although the craft failed to fire a pellet into the asteroid’s surface as planned, it did seemingly manage to disturb the asteroid’s surface enough to stir up dust which was captured by Hayabusa – about 1500 particles in all. Numerous tests carried out by JAXA (the Japanese space agency) have identified minerals including olivine, pyroxene, plagioclase and troilite.
The Royal Observatory, Greenwich will be showing a Hayabusa planetarium show next year as part of our forthcoming ‘Impact’ season.
Read more about asteroids in our fact file.
Youngest ‘nearby’ black hole
Astronomers in the US believe they have found a 50 million-year-old ‘baby’ black hole in the relatively nearby M100 galaxy (still 47 billion, billion miles from Earth).
Supernova remnant SN 1979C is the product of a blast observed just 30 years ago, and has been investigated by several telescopes including most recently NASA’s Chandra X-ray Observatory. All of these show that it is a bright source of X-rays which have remained steady for 15 years, strongly suggesting that it is a black hole. It probably formed when a star 20 times more massive than the Sun collapsed in on itself at the end of its life.
However, it is also possible that the source of the X-rays could be a young, fast-spinning neutron star with a strong wind of high-energy particles.
Read more about black holes in our fact file.
And finally… Tycho Brahe exhumed (again)
From dying stars to dead star-gazers – the body of the 16th-century Danish astronomer Tycho Brahe is being exhumed in Prague in an another attempt to determine the cause of his death.
The court mathematician, alchemist and astronomer who catalogued over 1000 stars led a colourful life, including a duel in which he lost his nose. It’s thought by some that high levels of mercury found in a previous exhumation may have resulted from deliberate poisoning, and suspicion has pointed to his assistant Johannes Kepler or to the Danish king Christian IV with whose mother Brahe allegedly had an affair.
Scientists also hope to determine the kind of metal Brahe’s nose prosthesis was made from.
Read more about Tycho Brahe and his star maps in our fact file.
Leonids
The annual Leonids meteor shower should now be visible and is due to reach its maximum on Wednesday 17 November. Astronomers expect about 10-20 meteors per hour at the peak, which is low to average for this shower. Best viewing time is likely to be the early hours of Wednesday morning, particularly after the Moon sets at around 4.00 am. As always, best meteor viewing needs dark skies away from city lights.
The Leonids are generally one of the more prolific annual meteor showers, with fast, bright meteors associated with Comet Tempel-Tuttle. The radiant (where the meteors appear to stream from) is at the head or ‘sickle’ of the constellation Leo, and meteors
can be seen each year over a period of several days centred on
approximately 17 November. Some of the meteors leave trails which can last for up to half an hour.
About every 33 years (the period of Tempel-Tuttle), the Leonids produce meteor ‘storms’ when hundreds
or even thousands of shooting stars can be seen. Such storms were seen in 1799, 1833,
1866, 1966 and 1999-2001 (although the expected 1899 and 1933 storms were disappointing). The 1833 storm was particularly spectacular, with an estimated 100,000 meteors per hour. The 1999-2001 storms produced about 3000 per hour.
Taurids and α-Monocerotids
As well as the Leonids, there is also the more minor Taurid meteor shower pair
(Southern Taurids and Northern Taurids). The main peak is coming to a close
now on 12 November, with a rate of about 8-10 meteors per hour, but the
showers continue until about 25 November, their radiants moving slowly
eastward across the constellation Taurus.
Finally, the minor α-Monocerotids shower will be active between 15-25 November, with a peak rate of only about 5 meteors per hour on the evening of 21 November. Very occasionally the shower produces a much stronger outburst but the next such event isn’t expected until 2043.
Image: Leonid shower; photo by Thomas Paulech and Juraj Toth, Bratislava, Slovakia