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6.7 Meter Telescope To Capture 30 Terabytes Per Night
Posted by
Soulskill
on Sat Oct 04, 2008 01:09 AM
from the very-large-yet-very-small dept.
from the very-large-yet-very-small dept.
Lumenary7204 writes "The Register has a story about the Large Synoptic Survey Telescope, a project to build a 6.7 meter effective-diameter ground-based telescope that will be used to map some of the faintest objects in the night sky. Jeff Kantor, the LSST Project Data Manager, indicates that the telescope should be in operation by 2016, will generate around 30 terabytes of data per night, and will 'open a movie-like window on objects that change or move on rapid timescales: exploding supernovae, potentially hazardous near-Earth asteroids, and distant Kuiper Belt Objects.' The end result will be a 150 petabyte database containing one of the most detailed surveys of the universe ever undertaken by a ground-based telescope. The telescope's 8.4 meter mirror blank was recently unveiled at the University of Arizona's Mirror Lab in Tucson."
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"Perfect" Mirrors Cast For LSST 114 comments
eldavojohn writes "The Large Synoptic Survey Telescope (which was partially funded by Gates & Co.) announced a world record casting for its single-piece primary and tertiary mirror blanks, cast at the University of Arizona. From the announcement: 'The Mirror Lab team opened the furnace for a close-up look at the cooled 51,900-pound mirror blank, which consists of an outer 27.5-foot diameter (8.4-meter) primary mirror and an inner 16.5-foot (5-meter) third mirror cast in one mold. It is the first time a combined primary and tertiary mirror has been produced on such a large scale.'"
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Re: (Score:3, Interesting)
we might be reaching the physical (or practical) limit of data density for hard disk platters, but we'll probably just move to new technologies. it's very unlikely that magnetic disk drives are the pinnacle of data storage technology. there are probably more efficient storage mediums in the works already.
i don't know what can currently match magnetic disks drives in terms of IO speed, but holographic storage [wikipedia.org] shows a lot of promise. in theory, holographic storage can read/write millions of bits of data in pa
Holographic Storage = No More Bad Sectors? (Score:2)
Presuming that the phenomenen reported by Lysergic Acid holds true and does, in fact, apply to holographic data storage:
> if you record a hologram of a 3D object onto a photographic
> plate, you can in essence reproduce a 3D image of the whole
> object with any piece of that photographic plate.
Would this mean the end of "bad sectors" as we know it?
It would seem to me that if a part of the holographic storage device degrades in some way, one could simply read the data from any number of different "win
Re: (Score:2)
This can be done without holography. The field of science that studies this is information theory [wikipedia.org]. By a proper encoding, one can put redundancy in any data set such that the original information can be recovered, no matter how muc
Re: (Score:2)
: "By a proper encoding, one can put redundancy
: in any data set such that the original information
: can be recovered, no matter how much degradation
: there is."
Granted, but according to the related article on channel capacity [wikipedia.org], the Shannon-Hartley theorem indicates that the maximum rate of data transmission across a noisy channel degrades logarithmically as noise increases linearly (if I am reading the article correctly).
Therefore, it would seem to me that the amount of data redundancy
Re: (Score:2)
Not to mention there is an even easier way,which is simply adding more slots and/or shrinking the sizes of drives. Hell my going on 5 year old machine has slots for 4 drives(2 EIDE and 2 SATA) and we are now seeing plenty of boards with 6 SATA slots or more. And as we have seen drives like chips can still be shrunk a ways. So I kinda doubt we'll be hitting the wall for awhile yet.
That said,where we ARE hitting a wall,and pretty hard at that,is easy to use consumer backup storage. The days of easily backin
Why not... (Score:1)
Re:Why not... (Score:5, Interesting)
The basic problem is that a 6.4 meter aperture can't fit in a launch vehicle, Ares V is only to be 5.5 meters.
Hubble was built at the diameter it was (2.4 meter) because thats about the maximum you could build of a stiff mirror that held its shape well enough through launch to remain optically sound on orbit. When you require 10-nm level precision, it takes a hefty structure to keep things that stiff.
In order to go bigger, the methods they're using for James Webb manage to double the aperture while halving the weight. The way they do this is using active controls and sensors to correct errors rather than rely on avoiding all errors. But looking at James Webb, you'll notice it focuses on IR which is very hard to observe from Earth, while no optical band concept is out there. This is because the new, big Earth-bound scopes use adaptive optics to eliminate seeing errors (the variations in the atmosphere that Hubble avoids), and get potentially better images than Hubble since larger mirrors can be used.
Of course, if the money shows up, there are other advantages to having a space-based observatory, particularly access time and not having to worry about the effectiveness of the adaptive elements, so I'm sure we'll see a proper Hubble replacement eventually, but it's certainly not as critical for scientific progress as some might think.
Parent
Re: (Score:1)
Re: (Score:2)
So consider it a beta... I imagine that the reason its still on the ground is a lack of funding to get it up there... its far cheaper to set it up on the ground, and extremely cheap to fix and maintain in comparison, plus when its on the ground you (they) have essential complete control over it, when its in space you have to let other people play with your toy, or be sacrificed to debris...
I highly doubt this is the be-all, end-all of this telescope (or at least the work the people involved are/will do) or
Re: (Score:2, Informative)
This is why... (Score:5, Funny)
Re: (Score:2)
30TB raw? (Score:3, Interesting)
When I worked at the CFHT a few decades ago, they had a bunch of "data reduction" algorithms they ran on each night's run that reduced the amount of data they needed to store by at least a factor of 10.
Re:30TB raw? (Score:5, Funny)
Parent
Re:30TB raw? (Score:5, Funny)
Parent
Re: (Score:2)
Honestly, I don't know what the data reduction algorithms did. If I had to guess, I would guess that they included things like a high-pass filter to remove readings that were "in the noise" and maybe some sort of compression for repeated values over large areas like "empty space." Just guessing though.
Re: (Score:2, Informative)
Re: (Score:1)
Re: (Score:2)
What, like storing the year as two digits, that sort of thing?
I know you're trying to be to be a smartass, but BMP<->PNG for example? Both are lossless but one takes much, much more space than the other. I'm sure there's other and probably better ways of compressing that data that's really specific to the application, like say FLAC is to music. Though I would guess that's already applied...
Re: (Score:1)
30TB can hold a lot of duplicate stories! (Score:1, Informative)
What does this story add that the following LSST stories didn't?
http://science.slashdot.org/article.pl?sid=07/01/10/0111227
http://science.slashdot.org/article.pl?sid=08/04/22/0116259
http://science.slashdot.org/article.pl?sid=08/09/02/2346240
Re: (Score:1, Redundant)
This one was posted most recently, its fresh and clean... for us to poop on.
Any colour you like so long... (Score:5, Funny)
30 Terabytes, consisting mainly of #000000.
mainly... (Score:1)
Re: (Score:1)
Re:Any colour you like so long... (Score:4, Interesting)
Parent
Re: (Score:2)
I'm no astronomer or physicist but isn't the fact that there is so much dark sky, even with powerful telescopes, suggestive of the presence of dark matter?
How bright would the night sky be if there were no dark space visible to the naked eye?
Re: (Score:2)
No, but the existence of dark sky *is* interesting.
Look up Olbers' paradox [wikipedia.org]. Any matter that respects the laws of thermodinamics (be it dust, interstellar gas or the newly defined "dark matter") should heat up to the temperature of its ambient medium and start radiating, so absorbtion can't be an explanation for the dark sky. There are however other th
Re: (Score:1)
it will run on MySQL (Score:5, Informative)
This project was presented at the MySQL Users Conference 2008 in a dedicated talk and a keynote.
The storage will be organized in clusters based on MySQL databases.
Astronomy, Petabytes, and MySQL [oreilly.com]
The Science and Fiction of Petascale Analytics [oreilly.com]
Sounds like a big number, but.. (Score:5, Informative)
30 TB per night sounds like a lot, but 1.5 TB drives are about AUD 350 each, retail. By 2016, I'd expect vendors to have released at least a 10 TB hard drive at that price point, and I wouldn't be surprised if we're using 30 to 50 TB drives.
So it all boils down to about $1000 per night of operation, or about $350K per year. Not exactly expensive for a science project. A single mars mission costs about $300M, but this telescope would generate more discoveries. That's not even considering that storage costs would continue to drop over the lifetime of the telescope, so the eventual total cost may be less than $100K per year. That's the salary of just one person!
Re:Sounds like a big number, but.. (Score:4, Informative)
The cost of the storage might be reasonable, but what about the performance aspect? 30TB per night sounds like a lot to store in one night...being generous and calling a night 12 hours - I'm probably wrong, but I make that 43200 seconds which is 694 MB/s. Without looking up any performance stats for hard drives, that sounds fairly easily attainable (too).
Parent
It *IS* a big number! (Score:2)
Funny, but the idea of buying and installing twenty top-of-the-line new disks each day sounds like really big numbers to me...
Not to mention that they need backups. How many tapes do they have to buy? And data transfer, too. All those bytes are worthless if no one gets to see them, so they need at least 30 TB / day data link capacity.
But. . . (Score:1)
Nits and Grins (Score:4, Informative)
From TFA title: (emphasis added)
<nit>
That's 6.7 Meter effective diameter Telescope. The primary mirror has a diameter of 8.4m but the tertiary mirror (5.2m diameter) sits right in the middle of the primary, so its area needs to be subtracted from the primary. The area of the primary is pi*(8.4/2)^2 which is 55.4m^2 and the area of the tertiary is pi*(5.2/2)^2 which is 21.2m^2; a single mirror of that area would have a diameter of about 6.7m.
</nit>
<grin>
Hey!! I thought information wanted to be free! And here they plan to go off and capture 30 TERAbytes? Each night? OMG!!!!11Eleventy!! Say it ain't so!!
</grin>
Re: (Score:1)
<grin> Hey!! I thought information wanted to be free! And here they plan to go off and capture 30 TERAbytes? Each night? OMG!!!!11Eleventy!! Say it ain't so!! </grin>
what's the big deal? that's only .00000000003 yottabyte a night. :-)
That's all? (Score:1)
Jennifer Gates [wikipedia.org] was right, 640TB ought to be enough for anybody.
Re: (Score:1)
Loading this link in elinks produces the following:
Space got slashgarbaged (Score:1)
Slashdot took out the space in "Personal life."
Why the lenses? There's a better way! (Score:2)
This telescope is amazing. The three-mirror configuration gives sharp focus, over a very wide field...the only problem is that the focus is on a spherical surface.
The LSST fixes this by having three relatively small (small compared to the mirrors) lenses [llnl.gov] to flatten the field, and they use a very large image sensor.
I am curious if they considered using a non-flat image sensor. It would be hard, but with e-beam or UV-laser lithography, I would think that you would be able to build a big sensor on a curved s
Re: (Score:1)
They can thank ... (Score:2)
common with "large science" (Score:2)
Wow.... (Score:1)
Re: (Score:2)
What hard drives do they use? Gosh, how do their computers look? I mean if 1TB or 1.5TB hard drives really are the largest drives out there, then they would have to get like 150,000 hard drives!
Quantum do 112 drives in a 4U rack, which with controllers and raid, and assuming they've moved to 1.5TB drives since I last saw it (when it was 1TB) give you about a petabyte in a rack -- maid to reduce power consumption.
Pretty cheap too, under a million per rack.
Re: (Score:1, Troll)
CmdrTaco paid me 5 cents to suck his 2 inch penis!
Wow.. the economy's going to put yo mama outta bidness.