New Wide-Angle Telescope to Capture Night Sky

NewScientist is reporting that a new telescope located in Chile is aiming to capture images of the entire night sky every three nights. From the article: "The telescope will use a digital camera with 3 billion pixels to image the entire sky across three nights, producing an expected 30 terabytes of data per night. This will allow astronomers to detect objects that quickly change their position, such as near-Earth asteroids, or their brightness, such as supernovae."

Re:lots of questions ?

[Anonymous Coward]

Chile doesn't need to have their own supercomputers. The people funding it (RTFA) can ship them in. While Chile is one of the more prosperous South American countries, this is not Chile's project, and is probably only involved because they probably have the right site for the observatory.

Re:billion: 10^9 or 10^12 ?

[Surt]

You got rated funny, but just in case you wanted an answer, I'd be pretty confident that the new scientist, being in .com and not .uk, was using 10^9. I'd also guess that based on getting only 30 terabytes of data per night, with 10^12 I'm pretty sure they'd be into exabytes.

Re:Government funding?

[Anonymous Coward]

From TFA:

Funding is another hurdle. The telescope will cost an estimated $300 million, but so far telescope officials have only raised $30 million from private donors. "We would like the rest of the money to come from the federal government," says Sweeney. The telescope team will soon submit proposals for funding to the National Science Foundation and the Department of Energy. And the US Congress will need to approve the funding

Re:Prioritize our needs

[Anonymous Coward]

The short answer is, yes, we do. The other 8m+ class telescopes all have tiny fields of view. They are designed to stare for a long time at a fixed point in the sky to take 'deep' exposures. The LSST is designed to do survey work to measure weak lensing of galaxies. That requires looking at a large region of sky (so you can get as many galaxies as possible), and also requires the telescope to be a big 'light bucket' so the signal to noise in the individual pixels is good enough.

The reason they are doing this survey is because it is possible to invert the weak lensing map (which you can get by measuring the average distortions on huge numbers of galaxies) to produce a map of the distribution of matter in the universe. You can use the power spectrum of the matter distribution combined with the cosmic microwave background information from WMAP to try to investigate dark energy, the big unknown in science.

Basically, LSST's design is focused on trying to tackle the biggest problem in cosmology.

Re:30 terabytes of data per night

[Dr_LHA]

Mods, please don't mod this up. Its bullshit. True that Forth was in *1976* was made the official language of the IAU, but no astronomer uses Forth these days, and there's no hint anywhere that the guys who run this telescope are going to be using it either. These days Astronomers are more likely to use Python, Perl, C, C++, Java and other modern languages to write their data analysis tools in.

Re:30 terabytes of data per night

[RogerWilco]

Actually, most astronomers use FORTRAN there days. Packages like AIPS and MIRIAD are completely written in them.
The newer stuff like AIPS++ uses C++.

I'm working on one of these next-generation telescopes, it LOFAR, we hope to have it operational in 2008. All software is written in C++, except for some user interfaces in Java.

The telescope in the topic is only a dream at this point, they have nowhere near the funding to start yet. LOFAR on the other hand is already being build. Our software correlator is already running on our IBM BlueGene, making it the 9th fastest computer in the world. Our 144 GBit/s links to the sub-stations are operational, and the first full substation (of 77) will be operational next month.

These guys are talking 30 TByte/day, we're talking a raw datarate of 1.5 Petabyte/day at the end of 2008. This is going to be the largest radio-telescope in the world, at 300km (200 mi.), at least until SKA gets build (if it gets build)

It's a realy cool project :-)

Narrow?

[jpflip]

I'm not sure I'd call the study of the origin and structure of the entire universe "narrow", but be that as it may... The data set that will come out of this instrument (if it's ever built) will be on an entirely different scale than anything astronomers have had to deal with. There are lots of things that can be done with such an instrument - lensing surveys, redshift surveys, variable stars, supernova searches... Pretty much anything requiring a wide search where you don't know the exact locations of the interesting bits.

The Hubble (for example) will always be better if you want to look at a specific spot very closely, but a high resolution survey of the entire Southern sky every few nights is hardly of limited interest! My only concern is that it's too much - a few days of data could keep people busy for a very long time!

Re:Holy Storage Area Network Batman!

[Rakishi]

Particle accelerator experiments seem to regularly result in data from 10 to 100 terabytes. The Stanford Linear Accelerator has a db of over 800 terabytes and I believe it didn't cost too much to set up (not to mention I doubt it's exactly cutting edge anymore if it ever was), so such large data sets are already in use. Given that this data will be mostly black space and much of the rest will not change unexpectadly over time compression will make it a small problem in comparison to the onces I already listed.

Re:billion: 10^9 or 10^12 ?

[zippthorne]

No, that nomenclature is deprecated. SI [wikipedia.org] specifies 10^3 increments between each successive prefix [wikipedia.org]. and scientists pretty much universally use SI to describe measurements of all kinds.

Re:lots of questions ?

[andrew cooke]

here's a background paper on the "data challenge" - http://www.lsst.org/Project/docs/data-challenge.pd f [lsst.org]

Re:use distributed telescope arrays

[andrew cooke]

first, on the whole political thing:

the competition in astronomy is fierce. there's a fixed amount of money and a pile of good projects. there's a big peer-review process that evaluates possible projects and gives priorities. then the nsf goes round looking for dead wood it can hack away so that there's money for the best projects. no-one is complacent - i work at ctio and everyone there was assuming that they were going to lose their jobs. and because lsst won't really kick in for a few years, we may still be laid off before then (even though we're all working like crazy on related projects). this isn't a bunch of "has beens" making life easy for themselves - it's a vicious, competitive world where only projects that really stand a good chance of changing astronomy make it.

second, the technology choice:

if you are talking about synthetic apertures (like radio telescopes) then no - you cannot link optical telescopes together state-wide. you can control them in parallel, sure, but you cannot combine the data in the same way as radio telescopes. it's way beyond our technical ability. so if there is no synthetic aperture, what's the advantage in spreading them around? especially when world class telescope sites with existing support are very rare. it makes most sense to put one telescope on the top of a mountain in a chilean desert.

and don't think you can re-use any old telescope. the structural engineering of this thing is going to be brutal - to optimize throughput the slews (moving to a new position on the sky) are going to be way faster than anything currently out there. that's one reason the site decision had to be made early - they need to know what they're building this on just to control the vibration levels!

there is a competing project, called pan-stars, which has a group of co-located telescopes. the advantage of that approach is largely political - you can build one cheaply and then look for more funding. but if you do the maths - and this is well understood engineering/optics/statistics, the answer is clear - the lsst solution comes out on top.

oh, and it's not old news either; the press conference anouncing that this was going to chile was held in the room next to my office a few days ago.

Re:Holy Storage Area Network Batman!

[ErikZ]

Seriously though, commodity disk drives are at 500GB already.

750. A friend of mine just sent me the link from Newegg.

Re:Prioritize our needs

[Original Replica]

I personally do not feel that another 8m class telescope is what the community needs.
Are you suggesting that there are ways to spend 300 millon in Chile that might somehow better serve the community? At first I thought maybe schools or infrastructure might be better places for the cash, but after reading up on Chile in the World Factbook http://www.cia.gov/cia/publications/factbook/geos/ ci.html [cia.gov] I think that some high end scientific spending is quite appropriate. Now should that money come from US taxpayers? That's a different question.