I work at Steward Observatory, who is a major collaborator in the LSST project (and will make its mirror). The telescopes that Steward makes usually use Linux for the control systems, since it provides a reasonable level of real-time control capability and is fairly sane to administer. Telescope control requires getting rather close to the hardware, some thing that Windows is not especially good for. Our office is pretty much a 50-50 mix of Windows and Linux machines, with Windows used grudgingly in most cases for engineering software.
But they may use a big honkin' Microsoft data server farm to manage the images if they get that much money from Microsoft-enriched folks.
There is this thing called adaptive optics, which corrects for atmospheric turbulence by bending the secondary mirror in real time with 600 magnetic actuators. However, there is a bit of a problem making it work... the LBT being built by my employer Steward Observatory has had at least two of the 1 meter diameter, 1.6 mm thick secondary mirrors crack before installation (they currently have zero good adaptive secondaries). But when it works, as it has on the MMT, it works quite well.
If you read the fine source code linked to in the article, you would see that not only is the machine code disassembled, but the virtual machine that it implements is fully described. That's not a trivial exercise.
The distortions that adaptive optics corrects for result in the light from two places in the sky ending up on the same pixel of the detector array. That's rather hard to correct for with DSP, since you don't know which sky pixel to put that CCD pixel's photons into.
There are plenty of problems with adaptive optics, however. The folks I work with who work on the LBT say that they've managed to crack four secondaries in a row, with zero intact ones in existence. This is not surprising, given the secondary mirror's 1 meter diameter and 1.6mm thickness.
I too was apalled that the reporter didn't do *any* research to find out what the various steps of the process were. It seems that the advent of desktop journalism has produced a caliber of journalist that doesn't even realize that an informative article full of "I don't know..." is not good.
You are right about the solder paste squeegee machine and the soldering oven (the "adhesive" is solder) and BIOS programmer and hand-stuffing of connectors. The automatic assembly only works for brick-shaped surface mounted parts.
Efficency can take a second seat to low cost and ease of producing the equipment. Where I live, in Tucson AZ, there's enough solar power hitting my roof to power the whole block's houses. I just couldn't afford that many PV cells.
I am interested in a system that can provide some relief from the cost of heating and cooling my home without a big outlay in high-tech stuff. This ammonia cycle is something that I was thinking of just a few weeks ago.. Perhaps if I was a thermodynamic engineer instead of electrical engineer, it would be second nature to me.
My boss no longer lets the cleaning staff into his tiny office, which contains our group's server, because they managed one night to turn off the power strip on the floor under his desk that powers the server. I know, he ought to secure it better instead of leaving it on the floor. Good thing it's not a Fortune 500 company!
I heard that rumor about blue dye in fire alarms millions of times as a kid. Then, as a grown-up, I bought a red fire alarm control switch at a surplus store and installed it in my (party) house as the bathroom light switch. It had a hole that the blue dye was supposed to come out of, but it was just the Allen head set screw that held the cover closed.
[I also had an experience in high school that taught me how much the administrators knew, after I made a key to open every P.E. combo lock in the school. They told me that their locksmith said that what I had done was impossible.]
I'm married to an amputee, and I am not happy with the current administration's use of my tax dollars going to the other side of the world to cause a ruckus. It's nice that the government is finally supporting work in this area. It's one good outcome from this ill-conceived war.
Moore's Law (in its original 1965 form) strikes me as an observation of what engineers are comfortable doing if there are no physical constraints. That is to say, there will be a new generation of semi fab equipment built every 18 months, and it will be able to image twice as many transistors on the same area of silicon.
That's a 30% linear scale reduction, which is something that any engineer would be happy to pursue for the next version of their equipment.
Ask them to make it 50% smaller scale in the next verison, they'll tell you it can't be done. 15%? Too easy.
Where it gets weird is when the boss *requires* the engineers to do crazy stuff in order to "keep up with Moore's Law." That phase-shift stuff and the deep-UV sources come to mind.
Whaddaya mean? Newspapers are required by law to print no useful information at all in a scientific/technology article. They get bonuses for printing wrong information.
I think what a lot of Slashdotters would like to see is a record company that provides the cash and the expertise for producing the recordings, and then lets the artist have the rights to the masters to use as they see fit without worrying about the record company recouping its investment. This would be absolutely great for artists... it would be like finding a rich uncle or a bank that would give you a loan and never expect to be paid back.
I think what we'd like to see is the record companies stop demanding more and more money for the creative work of the artists *after* they're recouped their investment.
Cardboard's fine. Just don't assume that your styrofoam hat will block the goverment's secret terahertz ray. Where I work, they use styrofoam for dewar windows!
Bandpass filters are not typically used with the astronomical receivers I'm familiar with. They use a local oscillator operating a few gigahertz above or below the interesting signal and just mix it down to microwave. The usual receiver sees the imagefrequency as well as the desired frequency, but the latest generation uses a sideband-separating mixer with hybrid couplers at RF and IF ports to allow separate reception of upper and lower sidebands. The group I work in was the first to apply such receivers to actual astronomical use.
The microwave spectrum really ends at about 30 GHz, with the frequencies from 30G-300GHz called millimeter wave, and those from 300 GHz up called submillimeter. Terahertz technology is quite in its infancy. There was a terahertz conference last week, so the office I work in was pretty well cleared out. (I work on spectrometers that use what we consider low frequencies, The other thing about terahertz waves is that they behave quasi-optically, being focused by teflon lenses and blocked by cardboard. So it's not a radio band that one would use for cellphones.
I work on radiotelescopes that work at several hundreds of gigahertz, and the technology used there is rather exotic. There is also the slight problem of water absorption of the signal - our telescope at 10,500 ft (3200m) altitude has trouble getting a clear shot to space due to the atmosphere, so communication would have to be rather short-haul as in LAN.
LA has amazing surplus
on
A Space Junkyard
·
· Score: 4, Informative
My current favorite surplus place in LA is Apex Electronics, which is the electronics version of Norton's. Same idea - so much stuff you can't wrap your head around it, and aisles that collapsed in the '94 earthquake and haven't yet been restored to a vertical condition.
This place looks quite fun to visit. I'll have to check it out the next time I'm in the area.
Tell that to my 1958 Chevy station wagon. I don't know how many miles it has on the rebuilt original 283, since the odometer broke around 1998 with 193,000 miles (it shows 93000 since they only had 5 digits back then). I've even seen another 1958 Chevy wagon in Tucson that runs!
I guess so. However, one chief requirement of our application is "no BSOD" to prevent the telescope antenna crashing into the platform, so Windows was ruled out in about 12 nanoseconds.
I work at a university using Linux for a distibuted telescope control system. There was nothing in the persona list about either universities or machine control. I guess we're safe from the Microsoft marketing megamachine for now.
Slashdot Mirror
like this
If you define "the night sky" to mean "that portion of the sky visible at night from where you are located", then it is quite possible.
But they may use a big honkin' Microsoft data server farm to manage the images if they get that much money from Microsoft-enriched folks.
There is this thing called adaptive optics, which corrects for atmospheric turbulence by bending the secondary mirror in real time with 600 magnetic actuators. However, there is a bit of a problem making it work... the LBT being built by my employer Steward Observatory has had at least two of the 1 meter diameter, 1.6 mm thick secondary mirrors crack before installation (they currently have zero good adaptive secondaries). But when it works, as it has on the MMT, it works quite well.
If you read the fine source code linked to in the article, you would see that not only is the machine code disassembled, but the virtual machine that it implements is fully described. That's not a trivial exercise.
There are plenty of problems with adaptive optics, however. The folks I work with who work on the LBT say that they've managed to crack four secondaries in a row, with zero intact ones in existence. This is not surprising, given the secondary mirror's 1 meter diameter and 1.6mm thickness.
You are right about the solder paste squeegee machine and the soldering oven (the "adhesive" is solder) and BIOS programmer and hand-stuffing of connectors. The automatic assembly only works for brick-shaped surface mounted parts.
I am interested in a system that can provide some relief from the cost of heating and cooling my home without a big outlay in high-tech stuff. This ammonia cycle is something that I was thinking of just a few weeks ago.. Perhaps if I was a thermodynamic engineer instead of electrical engineer, it would be second nature to me.
My boss no longer lets the cleaning staff into his tiny office, which contains our group's server, because they managed one night to turn off the power strip on the floor under his desk that powers the server. I know, he ought to secure it better instead of leaving it on the floor. Good thing it's not a Fortune 500 company!
[I also had an experience in high school that taught me how much the administrators knew, after I made a key to open every P.E. combo lock in the school. They told me that their locksmith said that what I had done was impossible.]
I'm married to an amputee, and I am not happy with the current administration's use of my tax dollars going to the other side of the world to cause a ruckus. It's nice that the government is finally supporting work in this area. It's one good outcome from this ill-conceived war.
That's a 30% linear scale reduction, which is something that any engineer would be happy to pursue for the next version of their equipment.
Ask them to make it 50% smaller scale in the next verison, they'll tell you it can't be done. 15%? Too easy.
Where it gets weird is when the boss *requires* the engineers to do crazy stuff in order to "keep up with Moore's Law." That phase-shift stuff and the deep-UV sources come to mind.
Whaddaya mean? Newspapers are required by law to print no useful information at all in a scientific/technology article. They get bonuses for printing wrong information.
I think what we'd like to see is the record companies stop demanding more and more money for the creative work of the artists *after* they're recouped their investment.
Cardboard's fine. Just don't assume that your styrofoam hat will block the goverment's secret terahertz ray. Where I work, they use styrofoam for dewar windows!
Bandpass filters are not typically used with the astronomical receivers I'm familiar with. They use a local oscillator operating a few gigahertz above or below the interesting signal and just mix it down to microwave. The usual receiver sees the imagefrequency as well as the desired frequency, but the latest generation uses a sideband-separating mixer with hybrid couplers at RF and IF ports to allow separate reception of upper and lower sidebands. The group I work in was the first to apply such receivers to actual astronomical use.
Are you kidding? you can't do first post if you RTFA!
The microwave spectrum really ends at about 30 GHz, with the frequencies from 30G-300GHz called millimeter wave, and those from 300 GHz up called submillimeter. Terahertz technology is quite in its infancy. There was a terahertz conference last week, so the office I work in was pretty well cleared out. (I work on spectrometers that use what we consider low frequencies, The other thing about terahertz waves is that they behave quasi-optically, being focused by teflon lenses and blocked by cardboard. So it's not a radio band that one would use for cellphones.
I work on radiotelescopes that work at several hundreds of gigahertz, and the technology used there is rather exotic. There is also the slight problem of water absorption of the signal - our telescope at 10,500 ft (3200m) altitude has trouble getting a clear shot to space due to the atmosphere, so communication would have to be rather short-haul as in LAN.
This place looks quite fun to visit. I'll have to check it out the next time I'm in the area.
Tell that to my 1958 Chevy station wagon. I don't know how many miles it has on the rebuilt original 283, since the odometer broke around 1998 with 193,000 miles (it shows 93000 since they only had 5 digits back then). I've even seen another 1958 Chevy wagon in Tucson that runs!
He didn't mention that he gets to coast *down* the 900 foot hill each way also. Slacker!
I guess so. However, one chief requirement of our application is "no BSOD" to prevent the telescope antenna crashing into the platform, so Windows was ruled out in about 12 nanoseconds.
I work at a university using Linux for a distibuted telescope control system. There was nothing in the persona list about either universities or machine control. I guess we're safe from the Microsoft marketing megamachine for now.
Uh, shouldn't that be a two gig flash chip, not two meg? X is a bit bigger than two megs, last time I checked.