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Sloan Digital Sky Survey
Swannie writes: "There's a story in today's Chicago Tribune about a joint project that Fermi Lab is taking on with Rensselaer Polytechnic Institute in New York. The goal is to produce a 3D map of the universe using a really big digital camera, and a really creative way to add "depth" to the image. The article has some decent technical details for a newspaper, including a pretty picture." Update: 03/12 15:44 GMT by M : The blurb is in error. A particular scientist from Rensselaer is mentioned in the article, but Rensselaer isn't part of the project as an institution.
I've been playing around with this prog, it has quite a big 3d map in it.
Howdy all. I've been following the project online for over a year. The cool part is that this is sort of a googlebot for the heavens. See: http://www.astronomy.com/content/dynamic/articles/ 000/000/000/502vwthx.asp
Now the 2df galaxy cluster mapping project which are giving us maps of our galaxy's position out to about 1B light-years -- /that's/ interesting AND news. hell,
"None are more hopelessly enslaved than those who falsely believe they are free." -- Goethe
Three dits, four dits, two dits, dah!
Radio, radio, rah rah rah!
There are several reasons why this hasn't been done.
- The amount of data is fairly trivial compared to the Particle Physics data (AstroGrid, EU DataGrid, Grid Forum
- Trust. As in lack there of. SETI had problems with people returning bogus results in the past and had to spend time (and several articles) on improving security and getting the same unit processed by several seperate users.
- Lack of man power / time.
- Dependability - e.g. an astronomer wants to run an analysis now! Is there any certainty that there will be x amount of processing power available? That your computer will still be on the network in 5 minutes time? That the unit will get processed in a reasonable real time?
It's ok for seti to send out a unit and not get it back for a week, or a month but not for things which have to be done right now. More importantly seti units are discrete, they dont depend on other units for the results.Physics data can & therefore any machine would have to have an always on connection to communicate with other machines. Bye Bye to your bandwidth.
The quality of astronomy grade CCD chips is so far beyond anything you've seen in commercial digital cameras, and so much more expensive. I've used a 2048x2048 chip, cost on the order of 50k, and keep in mind when they sell it to you you don't get anything but the chip, you have to build the rest yourself. Oh yeah, I wouldn't be waiting around to make a webcam, the single readout time for the full chip was about 2 minutes. Luckily this particular chip was recently upgraded to quad readout.
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Striving to put right what once went wrong, and hoping each time that his next leap, will be the leap ho
Automated object identification is already a standard part of any sky survey data pipeline. Among other things, this is used by surveys like SDSS to not only find and identify objects, but to tag the ones that are galaxies for later redshift measurement. (That's where the "3D" part comes in - redshifts of galaxies. Measuring radial ditances to closer objects - say stars in our own galaxy - is a pretty involved bootstrapping process where distance is derived from a ladder of indirect indicators.)
As far as grid computing goes, the US NVO (National Virtual Observatory) will implement a grid computing model. The NVO will be a unified portal that will federate about 50 digital sky surveys. It will have a database of billions of objects with hundreds of characteristics each, and rich relational structure spanning those hundreds of dimensions. They'll use grid computing to perform astronomers' queries on those data. That's really the main reason why these sky surveys are being done - to allow astronomers to do their work by data mining. A "map" of the universe will be a byproduct.