Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 internet speed test! ×

Comment Re:Thoughts (Score 1) 129

Even sadder is that, with the ongoing budget cuts, it's possible that those satellites won't be launched. It's just in brainstorming phase, where propositions are being made, and if something sufficiently scientifically compelling to worth the resources is proposed, then _maybe_ it will proceed to planning phase.

Comment Re:...and ground based is better now (Score 2) 37

I'm going for a further informative note here, noting exactly how this compensation is done.

It's entirely true that modern telescopes have the ability to compensate for most of the atmospheric effects, and this is why there are major efforts in building larger telescopes, such as the E-ELT. But for certain wavelengths, the atmosphere is almost completely opaque, making ground observations ineffective, and requiring the use of satellites for these observations. Also, light pollution is also a major problem that worsens day by day, and moonlight creates considerable problems under the atmosphere, even in a dark site.

Since the dawn of digital image and data processing techniques, the modern telescopes and observatories are able to compensate for atmospheric extinction or absorption effects. This effect varies depending on the location and altitude, and this is why higher-ground observatories are preferred, and the local extinction curve can be very accurately measured and applied to the captured data.

Another breakthrough was the implementation of active and adaptive optics. Active optics are used to compensate mechanical, thermal and construction limitations of larger mirrors, by using an actuator matrix on the primary, secondary or both mirrors of the telescope. Adaptive optics uses a guide star - either a natural one or an artificial one (see: sodium laser guide star), to compensate for atmospheric lensing and scatter effects. The light from the guide star is used to control the actuators on an auxiliary mirror, thus compensating for these atmospheric effects.

Comment Re:Why not just the best observing sites? (Score 2) 37

It's true that the northern hemisphere had the majority important telescopes... several decades ago. Actually, interest in installing telescopes to study the southern sky began as early as 1820, when Great Britain founded the Royal Observatory at the Cape of Good Hope, the first scientific institution in Africa. Following a few mergers and changes, the South African Astronomical Observatory was established in 1972, now operating one of the largest telescopes in the world - a 9.2 meter reflector telescope, the SALT, completed in 2005. In 1972 Another major southern telescope was built in 1974, in Australia, at the Siding Spring Observatory, housing the AAT, a 3.9 meter telescope.

The first modern large-scale reflector telescopes, that used photographic plates and films, were built at the beginning of the 20th century. The first telescopes having the primary mirror with a diameter larger than 1 meter were the Hale telescope (1908) and the Hooker telescope (1917), at Mount Wilson Observatory. After the vacuum evaporation coating technique was developed at CalTech, larger primary mirror diameters were possible, and for many years the 1948-built Hale reflector telescope at Mount Palomar was the largest telescope in the world having 510 cm primary mirror diameter. So far, most of the large telescopes were in the northern hemisphere.

In 1953, a shared European Observatory is discussed for the first time, and one year later it was established that this observatory will be placed in the southern hemisphere. The ESO charter is signed (ESO is celebrating 50 years these days, btw), and in 1966 the first telescope used in Chile received its first light. Right now, ESO is operaing one of the most advanced optical instruments, the VLT, which is actually an interferometer using four 8.2 meter main telescopes and four 1.8 meter auxiliary telescopes. Plans are under way to building the EELT, a 39 meter main mirror optical/near-infrared telescope, which will be the largest telescope on Earth by the time of its completion.

In conclusion, we have lots of world-leading telescopes in the southern hemisphere that hunt for planets using multiple techniques, including Doppler-shift spectroscopy, transit and direct imaging.

Comment Re:It's about time (Score 1) 280

If this move will give better, well-publicized results, others will follow. DRM only encumbers legitimate users, while those who want to pirate the books can find them anyway.

I'm certainly not reading a 400 page tome on my phone.

I have read dozens of books on multiple phones, some having more than 500 pages, and I enjoyed it. I started a couple of years ago after I finished reading all the books at my place and wanted more, so I purchased a couple of Iaim M. Banks e-books that weren't yet published in my country, wrongly thinking it should work on my old WM6 PDA, but guess what: there were no apps that support that specific DRM format, so I had to find them elsewhere. A while later, I switched on an Android Phone which had a better screen for reading but after this DRM experience, I avoid buying e-books having this protection.

Related on reading books on mobile phones, it just takes some time to get used, but I have no problem reading small text. I know not everyone can adapt to that, but I enjoy it, since it's small, multi-functional, and I can easily use it in transit.

Comment Re:And? (Score 1) 615

The flash authentication can be a good idea, but it can be lost, stolen or broken in several ways, so it would require a recovery mechanism. There is also a problem on high-security systems, such as governmental machines, where most I/O ports are sealed, including USB ports.

Comment Re:Hot Jupiter, yawn (Score 1) 124

Without decent pictures this story will not go far beyond the science pages. A graph showing distribution of elements isn't the most attention-grabbing shot I can think of.

That's why the media industry uses 'artist's illustrations' (like this), along with other existing images and resources, such as the telescope and a video of its launch.

Comment Re:Impossible in this timespan (Score 4, Informative) 171

From TFA:

"This little cosmic surprise, designated 2009 DD45, turned up two days ago as a 19th-magnitude blip in images taken by Rob McNaught at Siding Spring Observatory in Australia. It was already within 1.5 million miles of Earth and closing fast."

So no, they had no prior info about this asteroid. And yes, this fact concerns me as well, but this is the problem with asteroids / comets having a low albedo - they're difficult to observe with the usual instruments.

Slashdot Top Deals

Never tell people how to do things. Tell them WHAT to do and they will surprise you with their ingenuity. -- Gen. George S. Patton, Jr.