Exceptional Seeing At Dome C in Antarctica 252
Michael Ashley writes "A paper published in Nature
today reports on the exceptional
astronomical seeing conditions at Dome C (Coral link)
in Antarctica. Obtaining the data posed some significant technological
challenges, given that Dome C is uninhabited over winter. The
experiment was controlled by a PC/104
computer system that had to survive temperatures down to -85C, and
supervise the generation of its own electricity using a jet-fuel
powered stirling engine. The computer, running Linux, communicated with
the outside world using an Iridium
phone. The results are also covered in New
Scientist, and the Sydney
Morning Herald. Disclaimer: I'm a co-author."
Three cheers for global pollution (Score:5, Funny)
Re:Three cheers for global pollution (Score:5, Funny)
This [unsw.edu.au] poor motherfucker is the one that is actually there in the Winter (when they claim the telescope is controlled via sat. phone). Notice how *HE* can see!
The other guys are such wimps. Fur lined face masks and goggles. Sheesh!
Warning for those in Antartica... (Score:4, Funny)
Last we heard, one of their sled dogs were running this way with a helecopter following it....
Re:Warning for those in Antartica... (Score:2)
Re:Warning for those in Antartica... [OT] (Score:3, Informative)
The 'a' I believe stands for 'anchor', and 'href' for HTTP Reference. Note the '/' before the 'a' in the closing tag, it's important.
the hole in the ozone is good for something (Score:2, Funny)
Vow (Score:4, Funny)
Now, that's a savage dome!
Re:Vow (Score:4, Funny)
Surviving temps down to -85??? (Score:4, Insightful)
Wait a sec! =-P Computing equipment *loves* cold, as long as you don't have to worry about condensation. =-P In other words, it's not hard to design a system that can survive -85C. Just do a google search for Liquid nitrogen cooling [google.com]. Yay for overclocking fiends who make it so you don't even need to mention computing hardware.
btw, there's a tom's hardware link on the results page. Check it out. There's a pic of a CPU mount covered in frost. That *can't* be good! =-P
Re:Surviving temps down to -85??? (Score:5, Insightful)
Re:Surviving temps down to -85??? (Score:4, Funny)
Re:Surviving temps down to -85??? (Score:2, Informative)
You can actually, but I guess cost/benefit comes into it.
I live near Christchurch, New Zealand and once or twice a winter a fully loaded hercules takes off for an emergency trip to Antarctica to rescue some poor bastard that has broken an appendage etc.
Re:Surviving temps down to -85??? (Score:5, Informative)
While colder can often mean faster, sometimes a signal requires some minimum delay to work correctly. This is especially true of the minimum hold times required on inputs after a clock transition. So it's possible that some signal might go out of spec if you drop the temperature too far. It only takes a single bad signal to hose the whole system.
Unlike just dropping the temperature of the CPU chip which will have relatively uniform characteristics, getting the whole system cold might cause a wider range of timing variations. Moreover, even dropping the external heat sink of a CPU to extreme cold doesn't mean the chip itself is in the cryogenic range. They usually run at temps well above the bulk of the heatsink.
Re:Surviving temps down to -85??? (Score:2)
Re:Surviving temps down to -85??? (Score:3, Interesting)
My guess is that due to power restraints, the computer spends most of it's time powered off, or atleast in an extremely low power state.
Re:Surviving temps down to -85??? (Score:2)
Re:Surviving temps down to -85??? (Score:5, Interesting)
Re:Surviving temps down to -85??? (Score:5, Informative)
Ah, not so! *processor cores* love cold, not electronics in general. Specifically, electrolytic capacitors freeze and fail below their rated temperature, and it's really tough to find any that are rated to temps that low. Also, because of resistance, capacitance, and crystal frequency value changes at low temps, oscillators and filters tend not to behave. This doesn't even consider the issue of thermal expansion coefficient differences causing BGA chips to pop off the circuit boards! Making anything electronic operate in that environment is highly non-trivial.
Re:Surviving temps down to -85??? (Score:3, Informative)
Some electronics operates below its specified minimum operating temperature, and some doesn't. For example, we had some solid-state disks that were rated to -40C, but that failed at -20C. Mostly we have found that PC/104 computers, memory, etc work fine at -60C. M-Systems solid-state disks have been very reliable.
You want to avoid spinning up a hard disk at -85C though! The altitude (4000m equivalent) also tends to be rough on hard disks (both due to the cooling problems and the smaller head-gap), which is
Re:Surviving temps down to -85??? (Score:2)
Re:Surviving temps down to -85??? (Score:3, Insightful)
strike
RTFA: solid state equipment (Score:4, Informative)
Last but not least. The user. You got to have some damn heavy mittens for -85C.
The article specifically says that they used solid-state hard drives. The system was operated remotely so I imagine no keyboard was used.
In addition, -85C was only the exterior surface temperature. One computer was installed under the surface with an average operating temperature of -57C. Another experiment was warmed by waste heat from the stirling engine.
Screen shot of web page on mobile phone (Score:5, Informative)
Look at this photo [unsw.edu.au]. It is the author's Kyocera mobile phone with a web page showing the temperatures, memory usage and free disk space. Says battery temperature is -34.5 (is that C or F?)
Re:Screen shot of web page on mobile phone (Score:5, Insightful)
google: -40 fahrenheit in celsius [google.com]
Re:Screen shot of web page on mobile phone (Score:3, Informative)
You don't need google to see where the degrees everybody else uses and the degrees the U.S. uses coincide.
Let x be that temperature.
Then from the usual conversion formula:
f = c * 1.8 + 32
x = x * 1.8 + 32
-0.8 x = 32
x = -40
Q.E.D.
Not that it matters all that much; all civilized countries figured out celsius degrees years ago.
...laura
Fahrenheit and Celsiusconverge... (Score:2)
Re:Fahrenheit and Celsiusconverge... (Score:2)
Re:Screen shot of web page on mobile phone (Score:2, Funny)
Seeing how it says -34.5C I'm guessing that would be C.
Re:Screen shot of web page on mobile phone (Score:3, Funny)
Re:Screen shot of web page on mobile phone (Score:2)
Re:Screen shot of web page on mobile phone (Score:2)
Re:Screen shot of web page on mobile phone (Score:2)
Seeing Conditions (Score:5, Informative)
"Seeing" is a term that astronomers use to quantify the turbulence in the atmosphere and how it affects observations from the ground. The stars appear to twinkle because of the effect of this turbulence. In conditions of bad seeing, the stars appear to twinkle vigorously, and the images that you take with your telescope are blurry. In conditions of good seeing, the stars appear more stable, and you can take very sharp images.
You'd think they'd have a cooler word for that...
Re:Seeing Conditions (Score:4, Funny)
I apologize in advance for recycling an old joke, but here are some ideas for 'cooler words' (and phrases):
Untwinkly.
Non-Twinklifying.
Steady-State Stars.
De Tinky Winkied Star.
Sluggish Stars (antonym of 'vigorous').
Lethargtic star viewing.
20/8 vision or 38,000 ft equivalent observatories (Score:3, Interesting)
You'd think they'd have a cooler word for that...
As someone with myopia, I'd suggest laymen's terms like "20/20" or "20/10" or whatever (what would it be? "20/8") to describe the improved perspicacity available in low turbulence air. [BTW, I'm looking into Lasik and wondering just how good my vision could get...]
Or, you could perhaps express it in terms of
Re:Seeing Conditions (Score:2)
It's a bird, it's a plane...No it's Tux (Score:5, Funny)
I would have to say Linux was the ideal choice in this case. Penguins are polar creatures. you know. I wonder how the Microsoft Rainbow-bee-man would've fared under such conditions.
Re:It's a bird, it's a plane...No it's Tux (Score:2, Funny)
Could have used an... (Score:4, Funny)
Re:Could have used an... (Score:2)
Someone has to ask ... (Score:2)
(Don't bother to mod this post up, I've got all the karma I could possibly spend.)
Re:Someone has to ask ... (Score:4, Informative)
CPU boards usually have an intel clone processor MACH86 or VIA Athena.
So they can run any OS your desktop can.
Re:Someone has to ask ... (Score:2, Insightful)
Heres our PC/104 supplier. We also use a GPIB card from National instruments connected to an Agilent Data logger. Add a Modem Card, Video Card, and two DMM32 Data Aquisition cards. Plus the DMM16 thats already on-board.
The new Athena Processors have video on-board, and faster CPU's.
I believe Intel sued over teh Mach86 processor and they had to switch.
Re:Someone has to ask ... (Score:5, Informative)
The "Mach86" you're thinking of is the ZFMicro ZFx86 chip. They are battling National Semiconductor, who produced these CPUs under contract for ZFMicro until ZFMicro was no longer able to pay their bills. Intel is not involved at all.
The other big PC/104 CPU vendors are Transmeta, STMicro (STPC), and AMD (Geode). Recently the Pentium 4-M have been popular for boards which don't need to support extended temperature.
PC/104 rocks for applications like this. Disclaimer: I work for a PC/104 company.
Re:Someone has to ask ... (Score:3, Informative)
Re:Someone has to ask ... (Score:3, Informative)
To operate our experiments over winter, when there was no one at Dome C, we had several problems to address:
1. For hardware reliability, we wanted to remove all moving parts in the computers, i.e., no disk drives, and no fans. So we used a small PC/104 form-factor computer system with solid-state disk drives.
2. We had to generate our own electricity. We took two approaches to this:
1. One experiment, ICECAM, relied entirely on a 5 kg pack of
Re:Someone has to ask ... (Score:2)
In short they are X86 micro motherboards. So yes, they will run linux.
Re:Someone has to ask ... (Score:2)
-nB
Re:Someone has to ask ... (Score:4, Informative)
Additionally, there is PC/104+ which includes the 32-bit PCI bus in a 4x2mm stackable connector on the opposite side as the ISA headers.
There are more features to PC/104 but the size and bus signals are the most important.
Corrected Link (Score:4, Informative)
As Captain Murphy would say.. (Score:2, Funny)
Re:As Captain Murphy would say.. (Score:2)
Iridium? Didn't they go bust? (Score:2)
Iridium? Didn't they go out of business a few years ago?
Or have they switched to niche markets like in this case?
Re:Iridium? Didn't they go bust? (Score:2, Interesting)
Re:Iridium? Didn't they go bust? (Score:3, Informative)
Re:Iridium? Didn't they go bust? (Score:5, Insightful)
So they went bankrupt, and no one would buy the system. It was a textbook case of a colossal business failure, and no one would touch it with a 10-ft pole. The judge hated to rule that a $5 billion infrastructure system burn up in the atmosphere, and luckily, at the last minute, Dan Colussy stepped in with a $25 million bid- less than half a cent on the dollar of initial construction costs, and swept it up.
Then what? The new Iridium Satellite LLC started cleanning up, which it's still doing. Very profitable. It turns out that, while it's impossible to recoup a $5 billion investment on a satellite phone system is impossible, recouping an investment 1/200 that size isn't so bad.
This happens a lot. (Score:4, Interesting)
A good portion of certain companies DSL setups was done this way.
Hmmm what can I say... (Score:2)
Cool!
PC/104 Computers... (Score:5, Interesting)
We've used PC/104 computers (running QNX 4.25) for everythign from Remote power stations, Fuel cells, even UAV's.
Re:PC/104 Computers... (Score:2)
Offtopic (Score:2)
Re:Offtopic (Score:4, Informative)
outta beew (Score:4, Funny)
Dome C: Weh, Biwwy daywed me to stiwck my tung to the waw. Oh, and we'we outta beew....
Re:outta beew (Score:5, Informative)
BTM
Re:outta beew (Score:2, Funny)
Mostly off topic (Score:3, Interesting)
Thanks
Re:Mostly off topic (Score:2, Insightful)
First thing i would do is refrain from asking job advise on slashdot.
Re:Mostly off topic (Score:5, Funny)
But when needed small fast OS, they used MS DOS (Score:5, Interesting)
Re:But when needed small fast OS, they used MS DOS (Score:3, Interesting)
Re:But when needed small fast OS, they used MS DOS (Score:2)
Energy saved is energy saved, but if it only takes 10 seconds to boot DOS, then take 20 seconds worth of pictures, would it really be worth it to have an OS that might take longer, just to have power management for the 20 total seconds of picture taking???
Re:But when needed small fast OS, they used MS DOS (Score:2)
I just wanted to mention the DOS power management issue since I think most people are not aware of it. It's kind of intuitive to assume that DOS being a small simple OS would naturally draw much less power than big ugly Linux or Windows, but this is not the case.
Re:But when needed small fast OS, they used MS DOS (Score:2)
Re:But when needed small fast OS, they used MS DOS (Score:2)
Re:But when needed small fast OS, they used MS DOS (Score:2)
Re:But when needed small fast OS, they used MS DOS (Score:3, Interesting)
Thermal Control (Score:4, Interesting)
The hard part would be coming up with a thermal control system that worked at both extremes, a hot summer day and the dead of winter.
geography question (Score:5, Funny)
Re:geography question (Score:2)
Well, the nazi base is just a few miles west of Kurt Russell's base. [imdb.com] So, they can't be too far apart.
Bigger geography question (Score:2)
Good sense of humor (Score:3, Funny)
And yet the Hubble is still better (Score:3, Interesting)
However, I think Site C shows promise for imaging sites that are not in the right plane for Hubble to get a look at, or where the long winter night would allow for extended exposures...
Obligatory plug - please check out my online novel [blogspot.com]
Re:And yet the Hubble is still better (Score:2, Informative)
Re:And yet the Hubble is still better (Score:3, Informative)
Re:And yet the Hubble is still better (Score:4, Informative)
The total budget is 4.3M GBP, including new detector development, and the telescope will be collecting data from Austral winter 2007 onwards. This telescope will have better results on CMB B-mode polarisation than the Planck satelite mission, before Planck reports results, for about a tenth to hundredth of the cost. The Planck project has a 15 year head start. Admittedly Planck isn't designed to only make the measurements we are trying to make.
When something goes wrong, we'll be able to send someone out to fix it, and if someone invents better detectors, we can send some out to be installed.
Hubble is limited to the resolution of its 2m mirror, while optical telescopes on the ground are now reaching 10m (Keck), with sub-mm telescopes reaching 50-100m (LMT and GBT).
Hershcel/First will be the sub-mm equivalent to Hubble, and is limited to a single 3m mirror, while ground based sub-mm telescopes are using 64 15m mirrors spread across 60 km of the Atacama desert, simulating the resolution of a 60 km mirror.
Iridium phone? (Score:4, Funny)
Antarctica at night? (Score:3, Interesting)
Banana oil! (Score:2)
$1,000 to buy clothing for our chosen destinations. You hike through the molten lava fields into the active volcano and back out (ha!), and I'll hike the equivalent distance across any part of the south polar shelf. Who's going to be alive when the helicopter comes back?
Sterling engine? (Score:3, Informative)
Okay I'm interested in seeing this jet-fuel stirling engine. How well does it work in extreme cold?
For those of you who may not know much about stirling engines, here's some information. [stirlingengine.com]
Re:Sterling engine? (Score:3, Informative)
Simple Solution - Prescott Time (Score:2)
Simple solution, just put a Pentium 4 Prescott in there. Keep the whole place nice and toasty.
Now you can see the alien overlords coming... (Score:2, Funny)
"Quasi-Formulaic Investigations into the Space-Time Arrival Calculations of the Zarlanian Horde"
The paper is being rushed to press with journals such as Nature and New Scientist in the hopes of beating the inevitable alien invasion and, thus, enjoying the publicity prior to enslavement and/or annihilation.
"We're pretty excited about this second research opportunity. As soon as w
Really good war story (Score:4, Interesting)
Can you tell us about the dramatic events of 17 May 2004?
By 17 May 2004 the AASTINO had worked remotely for 100 days in 2004, and then something went wrong...
The WhisperGen engine has a control panel connected to it using an RS-485 bus running on CAT-5 cable. The control panel contains a microprocessor, and the engine expects to communicate with it regularly (at least once a second). When this communication is interrupted, the engine shuts down and reboots its own microprocessor.
Unfortunately, this is what happened on 17 May. - the engine went into a cycle of rebooting every 40 seconds. Once the engine has stopped, we had a ten hour window in which to try to restart it before the 200AH lead-acid batteries would lose too much capacity and become too cold for a restart (which requires 15A at 24V for about 15 minutes).
During this period we worked feverishly to come up with a solution. Our first priority was to shut down all unnecessary power consumption in the AASTINO - we can do this via a series of Dallas one-wire switches which control power to all the subsystems. A call to the engine manufacturer came up with the suggestion that we wiggle the CAT-5 cable connection - we suspect they forgot that we were over 4000 km away from our engine!
The PC/104 computer was also on the RS-485 bus, and we reasoned that by rewriting the Linux device driver (which we had written in the first place, so we knew what we were doing) we could make the computer impersonate the control panel, and convince the engine that it should keep running. Fortunately, we had a snapshot of the communication traffic between the engine and the control panel from earlier testing in the lab with the manufacturer's MSDOS-based software. But with no hardware available to test our code, we had to modify the driver, send patches over the 2400 baud Iridium link, and rmmod/insmod the driver to try to restart the engine.
All the while, the internal temperature of the AASTINO was plumetting towards ambient, at about -60C. We first modified the driver to allow the link traffic to be analysed, and this confirmed the communication problem with the control panel. After several attempts at generating fake packets from the control panel, punctuated by breaks in the Iridium link and agonizing waits for the system to redial (it is dialout only, controlled by a crontab entry), we were unable to prevent the engine from rebooting.
We watched helplessly as the battery temperatures sank below the minimum threshold for engine restart. Over the next 24 hours we received the occasional connection from the AASTINO computer, but that was all. We are now hoping that the solar panels will be able to recharge the batteries suffiently to re-establish communication before the Dome C station opens for the summer.
Cheap asteroid hunting (Score:2)
Probl
Re:Cheap asteroid hunting (Score:3, Informative)
When I froze mercury in the lab, it made a surface that wasn't optically useful -- lots of tiny bumps.
Also of interest: the century old Mt. Wilson 100-inch telescope used mercury bearings for the polar axis. In the 1970's, mercury pollution worried the operations staff; I don't know what was done about it.
Webpage with Telescope Health Data (Score:3, Informative)
There may be other tasties too -- I haven't dug too much.
Re:Mod submitter up... (Score:2)
Re:Mod submitter up... (Score:4, Funny)
Re:Mod submitter up... (Score:3, Funny)
Re:Dry Ice Boils at -78.5 C : ) (Score:2)