It may be too late in this discussion to explain the difference between the Mythbusters and the MIT experiments, but...
Basic thermo applied to optics means that no purely optical system can increase the surface brightness of an extended object. Old important optics theorem. Check any introductory textbook for the proof.
What this means is that, from the target's point of view, no part of the lens/mirror/whatever system is going to be any brighter or hotter or provide more energy per square degree than the sun does. Instead, the mirrors or lenses or whatnot only make it seem as if, from the targer's point of view, there are more suns covering more of the field of view.
Therefore, the limiting factors in the temperature the target will reach are the size of the optical system and how far away it is. If it's small enough or far enough that it appears, to the target, about the same size as the sun in the sky, it will provide about as much energy as the sun does, and the target temperature should roughly double. The weapon can't do any more, because it can't be any brighter than the sun itself.
On the other hand, a strong magnifying glass held near a twig covers at least half the sky from the twig's prospective, and all that area can provide as many watts per square degree as the surface of the sun. The sun, taking up something like a ten-thousandth of our sky, provides almost all the heat energy that keeps us and our planet alive. It's not hard to imagine what happens when, from a specific prospective, it suddenly seems to cover a tenth, or a half. Nearly-instant campfire. Or fried eyeball if the prospective happens to be yours.
This in mind, a quick look at the experimental setups from Mythbusters and MIT explains the difference in their results. The TV crew used a moderate sized cluster of mirrors at some distance from the target. Probably covered a few square degrees, or 8 or so sun areas. The collection of MIT students was fairly large and quite a bit closer, and covered far, far more of the target's 'sky' with sun image. It's no surprise that their target got quite a bit hotter. Personally, I'm not at all convinced that the MIT scheme could have been used during an actual battle. To duplicate their results would have required that either the soldiers move very close, or that they have a very large number of them.
For anyone who's interested, this ratio between the size, or _aperture_, of an optical system and the distance at which it brings light to a focus (the _focal_length_) is a common parameter used to describe the system known as the focal ratio or f-number. This is why two camera lenses of the same focal lengths but different f-numbers will require different exposure times to properly expose a piece of film or a CCD sensor.
And yes, for those who've checked, this explanation does directly contradict the FAQ from the MIT experiment's site. The professor argues that the distance isn't relevant to the results they got, because the light energy from their mirror system can be focused arbitrarily tight. That would be the case only if the sun was a point source rather than an extended object. If they had actually tried the experiment at more realistic distances they would have found that their mirrors projected images of the sun on the ship that were too large and blurred to heat it much, unless they added more students with mirrors to fill up more aperture and compensate.
The MIT class appears to have been an introduction prototyping and product validation. It intrigues me that, by misunderstanding the underlying theory, they ended up modifying a parameter that was actually crucial to their results and validating a scheme that would be, at best, cumbersome in the real world. What this implies for the design and test process is, ah, left as an exercise for the student.
Oh, absolutely. That will reliably be much faster. Because I've committed to memory all of the options and parameters that I'll ever need to use for wget, curl, grep, tar, sed, awk, bzip, the built-ins from several shells, etc, etc, etc. So I'll just whip off a simple shell script in 15 seconds or so.
Oh, wait, no I haven't. Guess I'll have to do what every user and most admin's I know do: If the task's significantly complex or going to be performed repeatedly, I'll spend 10 minutes poking through man pages or an O'Reilly book, and another 10 debugging. If it's something simple I'll just just do it by hand and be done.
One of the most significant advantages of a GUI is that it presents all of your options, even the infrequently used ones, at once -- no memory required. Since automating a task is, by definition, something you only have to do once, it's a perfect choice for GUIfication. I love my *nix shells, my OS/400 CL, I can even tolerate DOS.bat files when I have to, but from what I see here this technology would be at least an order of magnitude more useful to me than any of them.
Re:Call me cynical but where's the proof?
on
Mac mini to PC Hack
·
· Score: 1
Er, maybe I should start defrosting some crow. From what little I can find about the nano-ITX, looks like the daughtercard on the left of the assembled photo (pins up) is the DC-DC Power supply, And there's a screencap on mini-itx.com that's significantly more plausible than any of the stills. Did anyone here actually see the video?
Re:Call me cynical but where's the proof?
on
Mac mini to PC Hack
·
· Score: 1
Concur. Loudly. Note that even the photos linked from the words 'cut down the back I/O cover' show the unmodified cover and the port arrangements of the ITX board. No modifications show anywhere.
Nothing he describes is obviously impossible (though are Mac power supplies really that compatible? Didn't used to be) but there are no images that couldn't be produced by disassembling a mini, setting some PC parts on top of the case bottom, then putting everything back the way it was.
I hope I'm not being an ass to someone who worked hard on this, but the lack of visible modification in the pictures makes me very doubtful. Until proven otherwise I'm going to assume that Mr. Rose remembered the furor caused by the PC-in-a-gutted-G4 hoax and decided to yank on some chains. And did a damned good job of it, too.
Ms. Schulman is an SF reviewer for a PA newspaper, and very likely gets lots and LOTS of cool text in advance. She also seems to have used the opprotunity to claim the world's highest geek-quotient domain name. The lucky rat!
Er, the last estimates I heard from NASA had the Shuttle running about a 1% chance, per flight, of catastrophic failure. The astronaut corps knows it, it's a risk they're willing to take. And there's no shortage of volunteers.
Because the X-prize foundation was never able to raise the full ten million themselves. What they did instead was use the funds they had collected and insured themselves to the tune of ten million dollars against the chance of someone winning.
If someone wins in the new time frame, the insurance company gives back the principal and enough additional to total $10M, which will be given to the winner. If not the foundation forks over what's it's already got ('bout $5M, I think) to whoever wrote the policy. Nice simple hedge at roughly even money.
Interesting bet.
Unfortunately, one where the odds are going to get worse and worse the longer a time peroid you specify. I assume the foundation shopped around and found the best deadline they could based on the money they had in hand. Can't imagine how you actually calculate the odds on something like this but my gut tells me they got a pretty good deal
What will be done with the prize money if the deadline passes and no one wins?
It makes Munich Re. or Lloyds or some other company a little bit richer. Unfortunate, I guess, since it'd be nice to have the prize open until someone won, but certainly nothing shady or underhanded. I'm sure the foundation would rather have raised the whole sum directly, but it had stopped looking like that was going to happen, and the lack of full funding was said to be holding back at least one of the major competitors (but not others, which makes the decision more interesting).
A bit more explanation (part 2)
on
Beginning Astronomy?
·
· Score: 3, Informative
OK, Spent far too long explaining binoculars upthread, so I'll try to be more concise.
The Meade ETX telescopes mentioned above are what's known as go-to scopes. They use a computer, a pair of motors, and some reasonably simple initialization steps to find objects for you at at the push of a button, and to move the scope to keep it in view as the earth turns beneath your feet. This largely obviates the need to learn the sky, which is both good and bad. Good, because it gets you clear over the first hurdle upon which many beginners stumble. Bad because much of the money you've spent goes to pay for the computer and drives, rather than the optics, so the views you'll get will be somewhat poorer than comparably priced 'scopes of similar design.
The other extreme is the 'Dobsonian', elegantly planned scopes with bog-simple structures and mechanics, often mostly of cardboard and plywood, so that every available dime can be spent on the parts that actually harvest photons. Amazing views for the dollar, but you'll have to learn to find things yourself, and to keep nudging the scope along to keep them in view. Still, this is what most experienced amateurs of my acquaintance use and recommend, and I strongly suspect they're right.
What almost nobody seems to recommend anymore is the traditionally mounted small scope. These use a mechanical arrangement to allow the scope to follow objects across the sky, but they don't locate objects for you, and they have to be carefully aligned each time they're used if you want to take full advantage of the tracking. For certain applications, big, smooth, bulletproof (and often permanently installed) versions of these sorts of scope are perfect. But the one's you'll find in the price range in the article are typically flimsy, shaky, and really tough to use.
If you do decide to go whole hog and decide to both buy a telescope and start learning the sky, let me make two recommendations. The first is a 'zero-power finder', an inexpensive gadget like a head's up display for a telescope, or the red dot sight from a bb-gun (in fact, that's exactly what some of them are). It displays a glowing circle or dot that actually appears to be out there among the stars, at exactly the spot where the 'scope is pointed. There are other ways of finding things, but this is one of the easiest,
The other is a book called 'The Year Round Messier Marathon Field Guide' by Harvard Pennington. It shows maps for finding a hundred or so of the most popular observing targets (the Messier objects), such a way that slightly more experienced observers can find them all in one night (the 'Marathon'). The maps are marked up with simple geometrical constructions that make it clear that, for example, to find object a you should put the circle just about two thirds of the way along the line from stars b to c, maybe little skosh off in the direction of d. This was the book that finally got me over the hurdle from knowing how to find a handfull of things to knowing I can find whatever I want to badly enough, just by knowing how to read a star map in a certain way.
And even if the hobby turns out, in the end, not to be for you, let me recommend Sky and Telescope magazine. Observing's not everyone's cup of tea, but there's no better way for _anyone_ to keep up on the amazing discoveries that seem to be occurring almost weekly now than in S&T's clear and complete pages.
Finally, let me second (third, and fourth) the suggestion that you find and join your local astronomy club. There's a reason these thrive when most similar organizations are withering. All the info you can get from Slashdot is great, but it doesn't hold a candle to actually peering through other people's scopes before you choose your own, or asking navigation questions of someone who can stand beside you and point. Besides, nothing improves an amazing view like sharing it, and nothing can salvage a cloudy evening as well as an hour or two of coffee and astro-gab before calling it a night and heading home. Nope, not even Slash (though tonight, Slash is warmer)
HTH,
Chris
Is a bit more explanation in order?
on
Beginning Astronomy?
·
· Score: 3, Informative
Lot's of good advice in this thread already, but it seems to me that a few terms are getting tossed around without much explanation. Maybe a little more explanation will help some of the readers?
First of all, as for binoculars (a very good idea, IMO) they are described by a two number 'code' such as 7x50 or 10x70, where the first number represents the magnification and the second the size of the 'input' lenses (in mm). Surprisingly to most newbies, it's the second number that matters the most. The challenge in seeing many astronomical objects is not in making them bigger, but in making them brighter (there are exceptions, of course).
There's a catch, in that if you make the objective lenses too big without increasing the magnification accordingly you end up throwing a wider beam of light at your eye than can actually fit through your iris. The width of this beam of light is called the 'exit pupil' and you can figure it by dividing the objective size (the second number) by the magnification (the first).
So, for many years, astronomers were advised to get binocs that had this measurement as close as possible to 7mm, that being about as large as young, healthy pupils can get. Any larger and you'd be wasting light, any smaller and your magnification would be higher than optimal, spreading all that light your glass worked so hard to gather over a larger area, and thus lowering the brightness of any one part.
Nowdays, however, more experienced binocular observers than I have determined that some magnification is a good thing to have, too. They suggest different binoculars will show roughly the same amount if the product of the two description numbers is the same. Check the link above for details. I'm not sure I'm convinced, but I know one way to satisfy both criteria- I'll buy binoculars with a traditional exit pupil, but the very biggest one's I can handle.
Which brings us to the other numbers that describe a pair of binoculars. The price, about which no more needs to be said (except perhaps the occasional 'yikes!' form the underpaid sysape), and the weight. Larger binoculars are, of course, heavier. Heavier binoculars are really hard to hold steady enough to see things with when looking up. 7x50's seem to be about the limit for hand holding by most people. Maybe 10X70's if you're Conan. Anything much beyond that and you'll be looking for a photographer's tripod, or a beanbag perched atop a wall, or any of the other myriad gadgets astronomers have cooked up to hold their binoculars steady.
Gee, what a saga. I hope it's usefull to someone. Think I'll ramble about scopes such in another post.
Spent a week or two looking at this a while back, while setting up some unixy things at my old job, a 400 shop.
As has been mentioned, if all you need is green screen access to applications then there are a couple of terminal packages that speak the appropriate tounges.
If you require desktop printing functionality (attaching an OUTQ and WTR to your workstation printer) I think you're out of luck, though I'm not sure why. Protocol seems fairly simple. I'f I'd needed it badly enough I might have tried to hack something in. But I much preferred the chain printer up the hall for my 400 needs.
FSIOP/IPCS/ Integrated Netfinity Server's just an NT box on a card, with a disk subsystem like other NT's dream of. Speaks SMB just like the Proliant next door. No worries there.
The integrated file server sure looks like the same thing, but it's not. Not sure if it's an authentication issue, of if CA is speaking another protocol to the big black box and just patching the results into the SMB browser (network neighborhood). But without Client Access you aren't looking at those files. Probably not a problem as I understand we were one of very few shops still making extensive use of the feature.
Can't tell you about ODBC interoperability at all. Too hairy even to look at.
While we're on the subject, has anyone found a replacement for what was briefly the best cash-alternative ever; those American Express bearer cards that 7-Eleven sold? Those things were wonderful. Just as anonymous and secure as cash, but a whole lot more convenient to carry, and you could use them online, or for mail-order, or to buy gas at those damned places that refuse real money. Only real disadvantage was the cost, but they were competitive with many checking accounts and most credit cards. I can't see why they didn't sell more. Sure wish I could find something else like them.
Hmmm... You'd probably have to be crazier than I to try it, but what do you think would happen if you called your voice mail from a portable and announced "Good evening, Officer. This conversation is being transmitted, and recorded at a remote location."
Sure, they could still refuse you permission, or even smash your phone to bits and you afterwards, but that long silence at the end of the tape is going raise some real interesting questions in the mind of any judge or jury that hears it.
Like I said, it's probably not worth the risk, unless maybe you're a member of a group at high risk for police abuse. Nevertheless, I think I'll go max out the disconnect time on my voice mail at work. Just in case I ever want it.
Sorry, I'm not often moved to profanity in a public context, but I simply can't find another word that properly describes this... HORSECRAP! (there, there's another)
In an email published here the Apogee mouthpiece claimed:
Now suppose Duke Nukem Forever finally gets released, and I put a reivew up on my website. The review has a "Duke Nukem Forever" logo
First off, this would be illegal, unless you had prior permission. You cannot use trademarks without the owners permission. That's why we want to give fan sites permission, otherwise they cannot legally use own logos/trademarks and such. Review sites won't be dealing with us, only fan sites.
Which (must controll language) turns out not to be the case. There are lots of situations in which use of a trademark without permission is perfectly permissible. The most obvious is 'fair denominative trademark use', which says that you're allowed to call Duke Nukem Duke Nukem wherever you want -- even if you're calling him a chump.
Geez, don't these people remember the 'Barbie World' fiasco? How about Orbison v 2 live crew? Heck, all you have to do is look at McSpotlight to see how far this reaches
They might also do well to examine the extent of the 'parody' allowance. This one's not as clear as the nominative case, but it allows just about anything when it's upheld. If they really think they can close these first ammendment gaps in the trademark law by appealing to a UCITA license, I'm sure every civil liberties lawyer in the nation stands ready to disabuse them of this notion.
Actually, maybe it's time we make this point so clear they can't overlook it. I've got their site in my cache, the GIMP on my disk, and a restless urge to parody. Come on, some of you must run ISP's. Who's got a free meg and some courage?
Slashdot Mirror
It may be too late in this discussion to explain the difference between the Mythbusters and the MIT experiments, but...
Basic thermo applied to optics means that no purely optical system can increase the surface brightness of an extended object. Old important optics theorem. Check any introductory textbook for the proof.
What this means is that, from the target's point of view, no part of the lens/mirror/whatever system is going to be any brighter or hotter or provide more energy per square degree than the sun does. Instead, the mirrors or lenses or whatnot only make it seem as if, from the targer's point of view, there are more suns covering more of the field of view.
Therefore, the limiting factors in the temperature the target will reach are the size of the optical system and how far away it is. If it's small enough or far enough that it appears, to the target, about the same size as the sun in the sky, it will provide about as much energy as the sun does, and the target temperature should roughly double. The weapon can't do any more, because it can't be any brighter than the sun itself.
On the other hand, a strong magnifying glass held near a twig covers at least half the sky from the twig's prospective, and all that area can provide as many watts per square degree as the surface of the sun. The sun, taking up something like a ten-thousandth of our sky, provides almost all the heat energy that keeps us and our planet alive. It's not hard to imagine what happens when, from a specific prospective, it suddenly seems to cover a tenth, or a half. Nearly-instant campfire. Or fried eyeball if the prospective happens to be yours.
This in mind, a quick look at the experimental setups from Mythbusters and MIT explains the difference in their results. The TV crew used a moderate sized cluster of mirrors at some distance from the target. Probably covered a few square degrees, or 8 or so sun areas. The collection of MIT students was fairly large and quite a bit closer, and covered far, far more of the target's 'sky' with sun image. It's no surprise that their target got quite a bit hotter. Personally, I'm not at all convinced that the MIT scheme could have been used during an actual battle. To duplicate their results would have required that either the soldiers move very close, or that they have a very large number of them.
For anyone who's interested, this ratio between the size, or _aperture_, of an optical system and the distance at which it brings light to a focus (the _focal_length_) is a common parameter used to describe the system known as the focal ratio or f-number. This is why two camera lenses of the same focal lengths but different f-numbers will require different exposure times to properly expose a piece of film or a CCD sensor.
And yes, for those who've checked, this explanation does directly contradict the FAQ from the MIT experiment's site. The professor argues that the distance isn't relevant to the results they got, because the light energy from their mirror system can be focused arbitrarily tight. That would be the case only if the sun was a point source rather than an extended object. If they had actually tried the experiment at more realistic distances they would have found that their mirrors projected images of the sun on the ship that were too large and blurred to heat it much, unless they added more students with mirrors to fill up more aperture and compensate.
The MIT class appears to have been an introduction prototyping and product validation. It intrigues me that, by misunderstanding the underlying theory, they ended up modifying a parameter that was actually crucial to their results and validating a scheme that would be, at best, cumbersome in the real world. What this implies for the design and test process is, ah, left as an exercise for the student.
Oh, absolutely. That will reliably be much faster. Because I've committed to memory all of the options and parameters that I'll ever need to use for wget, curl, grep, tar, sed, awk, bzip, the built-ins from several shells, etc, etc, etc. So I'll just whip off a simple shell script in 15 seconds or so.
.bat files when I have to, but from what I see here this technology would be at least an order of magnitude more useful to me than any of them.
Oh, wait, no I haven't. Guess I'll have to do what every user and most admin's I know do: If the task's significantly complex or going to be performed repeatedly, I'll spend 10 minutes poking through man pages or an O'Reilly book, and another 10 debugging. If it's something simple I'll just just do it by hand and be done.
One of the most significant advantages of a GUI is that it presents all of your options, even the infrequently used ones, at once -- no memory required. Since automating a task is, by definition, something you only have to do once, it's a perfect choice for GUIfication. I love my *nix shells, my OS/400 CL, I can even tolerate DOS
Er, maybe I should start defrosting some crow. From what little I can find about the nano-ITX, looks like the daughtercard on the left of the assembled photo (pins up) is the DC-DC Power supply, And there's a screencap on mini-itx.com that's significantly more plausible than any of the stills. Did anyone here actually see the video?
Concur. Loudly. Note that even the photos linked from the words 'cut down the back I/O cover' show the unmodified cover and the port arrangements of the ITX board. No modifications show anywhere.
Nothing he describes is obviously impossible (though are Mac power supplies really that compatible? Didn't used to be) but there are no images that couldn't be produced by disassembling a mini, setting some PC parts on top of the case bottom, then putting everything back the way it was.
I hope I'm not being an ass to someone who worked hard on this, but the lack of visible modification in the pictures makes me very doubtful. Until proven otherwise I'm going to assume that Mr. Rose remembered the furor caused by the PC-in-a-gutted-G4 hoax and decided to yank on some chains. And did a damned good job of it, too.
The appropriate changes to HIKING trails? For a wheeled, motorized vehicle? Would those be caltrops and tripwires? Or just arming the wildlife?
Ms. Schulman is an SF reviewer for a PA newspaper, and very likely gets lots and LOTS of cool text in advance. She also seems to have used the opprotunity to claim the world's highest geek-quotient domain name. The lucky rat!
Er, the last estimates I heard from NASA had the Shuttle running about a 1% chance, per flight, of catastrophic failure. The astronaut corps knows it, it's a risk they're willing to take. And there's no shortage of volunteers.
Why was this requirement added?
Because the X-prize foundation was never able to raise the full ten million themselves. What they did instead was use the funds they had collected and insured themselves to the tune of ten million dollars against the chance of someone winning.
If someone wins in the new time frame, the insurance company gives back the principal and enough additional to total $10M, which will be given to the winner. If not the foundation forks over what's it's already got ('bout $5M, I think) to whoever wrote the policy. Nice simple hedge at roughly even money.
Interesting bet.
Unfortunately, one where the odds are going to get worse and worse the longer a time peroid you specify. I assume the foundation shopped around and found the best deadline they could based on the money they had in hand. Can't imagine how you actually calculate the odds on something like this but my gut tells me they got a pretty good deal
What will be done with the prize money if the deadline passes and no one wins?
It makes Munich Re. or Lloyds or some other company a little bit richer. Unfortunate, I guess, since it'd be nice to have the prize open until someone won, but certainly nothing shady or underhanded. I'm sure the foundation would rather have raised the whole sum directly, but it had stopped looking like that was going to happen, and the lack of full funding was said to be holding back at least one of the major competitors (but not others, which makes the decision more interesting).
OK, Spent far too long explaining binoculars upthread, so I'll try to be more concise.
The Meade ETX telescopes mentioned above are what's known as go-to scopes. They use a computer, a pair of motors, and some reasonably simple initialization steps to find objects for you at at the push of a button, and to move the scope to keep it in view as the earth turns beneath your feet. This largely obviates the need to learn the sky, which is both good and bad. Good, because it gets you clear over the first hurdle upon which many beginners stumble. Bad because much of the money you've spent goes to pay for the computer and drives, rather than the optics, so the views you'll get will be somewhat poorer than comparably priced 'scopes of similar design.
The other extreme is the 'Dobsonian', elegantly planned scopes with bog-simple structures and mechanics, often mostly of cardboard and plywood, so that every available dime can be spent on the parts that actually harvest photons. Amazing views for the dollar, but you'll have to learn to find things yourself, and to keep nudging the scope along to keep them in view. Still, this is what most experienced amateurs of my acquaintance use and recommend, and I strongly suspect they're right.
What almost nobody seems to recommend anymore is the traditionally mounted small scope. These use a mechanical arrangement to allow the scope to follow objects across the sky, but they don't locate objects for you, and they have to be carefully aligned each time they're used if you want to take full advantage of the tracking. For certain applications, big, smooth, bulletproof (and often permanently installed) versions of these sorts of scope are perfect. But the one's you'll find in the price range in the article are typically flimsy, shaky, and really tough to use.
If you do decide to go whole hog and decide to both buy a telescope and start learning the sky, let me make two recommendations. The first is a 'zero-power finder', an inexpensive gadget like a head's up display for a telescope, or the red dot sight from a bb-gun (in fact, that's exactly what some of them are). It displays a glowing circle or dot that actually appears to be out there among the stars, at exactly the spot where the 'scope is pointed. There are other ways of finding things, but this is one of the easiest,
The other is a book called 'The Year Round Messier Marathon Field Guide' by Harvard Pennington. It shows maps for finding a hundred or so of the most popular observing targets (the Messier objects), such a way that slightly more experienced observers can find them all in one night (the 'Marathon'). The maps are marked up with simple geometrical constructions that make it clear that, for example, to find object a you should put the circle just about two thirds of the way along the line from stars b to c, maybe little skosh off in the direction of d. This was the book that finally got me over the hurdle from knowing how to find a handfull of things to knowing I can find whatever I want to badly enough, just by knowing how to read a star map in a certain way.
And even if the hobby turns out, in the end, not to be for you, let me recommend Sky and Telescope magazine. Observing's not everyone's cup of tea, but there's no better way for _anyone_ to keep up on the amazing discoveries that seem to be occurring almost weekly now than in S&T's clear and complete pages.
Finally, let me second (third, and fourth) the suggestion that you find and join your local astronomy club. There's a reason these thrive when most similar organizations are withering. All the info you can get from Slashdot is great, but it doesn't hold a candle to actually peering through other people's scopes before you choose your own, or asking navigation questions of someone who can stand beside you and point. Besides, nothing improves an amazing view like sharing it, and nothing can salvage a cloudy evening as well as an hour or two of coffee and astro-gab before calling it a night and heading home. Nope, not even Slash (though tonight, Slash is warmer)
HTH,
Chris
First of all, as for binoculars (a very good idea, IMO) they are described by a two number 'code' such as 7x50 or 10x70, where the first number represents the magnification and the second the size of the 'input' lenses (in mm). Surprisingly to most newbies, it's the second number that matters the most. The challenge in seeing many astronomical objects is not in making them bigger, but in making them brighter (there are exceptions, of course).
There's a catch, in that if you make the objective lenses too big without increasing the magnification accordingly you end up throwing a wider beam of light at your eye than can actually fit through your iris. The width of this beam of light is called the 'exit pupil' and you can figure it by dividing the objective size (the second number) by the magnification (the first).
So, for many years, astronomers were advised to get binocs that had this measurement as close as possible to 7mm, that being about as large as young, healthy pupils can get. Any larger and you'd be wasting light, any smaller and your magnification would be higher than optimal, spreading all that light your glass worked so hard to gather over a larger area, and thus lowering the brightness of any one part.
Nowdays, however, more experienced binocular observers than I have determined that some magnification is a good thing to have, too. They suggest different binoculars will show roughly the same amount if the product of the two description numbers is the same. Check the link above for details. I'm not sure I'm convinced, but I know one way to satisfy both criteria- I'll buy binoculars with a traditional exit pupil, but the very biggest one's I can handle.
Which brings us to the other numbers that describe a pair of binoculars. The price, about which no more needs to be said (except perhaps the occasional 'yikes!' form the underpaid sysape), and the weight. Larger binoculars are, of course, heavier. Heavier binoculars are really hard to hold steady enough to see things with when looking up. 7x50's seem to be about the limit for hand holding by most people. Maybe 10X70's if you're Conan. Anything much beyond that and you'll be looking for a photographer's tripod, or a beanbag perched atop a wall, or any of the other myriad gadgets astronomers have cooked up to hold their binoculars steady.
Gee, what a saga. I hope it's usefull to someone. Think I'll ramble about scopes such in another post.
Spent a week or two looking at this a while back, while setting up some unixy things at my old job, a 400 shop.
As has been mentioned, if all you need is green screen access to applications then there are a couple of terminal packages that speak the appropriate tounges.
If you require desktop printing functionality (attaching an OUTQ and WTR to your workstation printer) I think you're out of luck, though I'm not sure why. Protocol seems fairly simple. I'f I'd needed it badly enough I might have tried to hack something in. But I much preferred the chain printer up the hall for my 400 needs.
FSIOP/IPCS/ Integrated Netfinity Server's just an NT box on a card, with a disk subsystem like other NT's dream of. Speaks SMB just like the Proliant next door. No worries there.
The integrated file server sure looks like the same thing, but it's not. Not sure if it's an authentication issue, of if CA is speaking another protocol to the big black box and just patching the results into the SMB browser (network neighborhood). But without Client Access you aren't looking at those files. Probably not a problem as I understand we were one of very few shops still making extensive use of the feature.
Can't tell you about ODBC interoperability at all. Too hairy even to look at.
HTH
While we're on the subject, has anyone found a replacement for what was briefly the best cash-alternative ever; those American Express bearer cards that 7-Eleven sold? Those things were wonderful. Just as anonymous and secure as cash, but a whole lot more convenient to carry, and you could use them online, or for mail-order, or to buy gas at those damned places that refuse real money. Only real disadvantage was the cost, but they were competitive with many checking accounts and most credit cards. I can't see why they didn't sell more. Sure wish I could find something else like them.
Hmmm... You'd probably have to be crazier than I to try it, but what do you think would happen if you called your voice mail from a portable and announced "Good evening, Officer. This conversation is being transmitted, and recorded at a remote location."
Sure, they could still refuse you permission, or even smash your phone to bits and you afterwards, but that long silence at the end of the tape is going raise some real interesting questions in the mind of any judge or jury that hears it.
Like I said, it's probably not worth the risk, unless maybe you're a member of a group at high risk for police abuse. Nevertheless, I think I'll go max out the disconnect time on my voice mail at work. Just in case I ever want it.
BULLSHIT!
Sorry, I'm not often moved to profanity in a public context, but I simply can't find another word that properly describes this... HORSECRAP! (there, there's another)
In an email published here the Apogee mouthpiece claimed:
Which (must controll language) turns out not to be the case. There are lots of situations in which use of a trademark without permission is perfectly permissible. The most obvious is 'fair denominative trademark use', which says that you're allowed to call Duke Nukem Duke Nukem wherever you want -- even if you're calling him a chump.
Geez, don't these people remember the 'Barbie World' fiasco? How about Orbison v 2 live crew? Heck, all you have to do is look at McSpotlight to see how far this reaches
They might also do well to examine the extent of the 'parody' allowance. This one's not as clear as the nominative case, but it allows just about anything when it's upheld. If they really think they can close these first ammendment gaps in the trademark law by appealing to a UCITA license, I'm sure every civil liberties lawyer in the nation stands ready to disabuse them of this notion.
Actually, maybe it's time we make this point so clear they can't overlook it. I've got their site in my cache, the GIMP on my disk, and a restless urge to parody. Come on, some of you must run ISP's. Who's got a free meg and some courage?
-- csh