How many Lumens can blind you?
I am curios to find out why you wish to know this. The eye has a remarkable ability to recover from bright light source so to damage the retina enough to achieve total blindness one would need to look into a bright light source (such as an arc light at close range) for quite while, and this is likely to take a lot of will power. And believe me there is a distinct such an injury is VERY likely to be EXTREMELY painfull. DEFINITELY NOT RECOMMENDED. Lindsay ----- Original message ----- From: "David Turk via luv-talk" <luv-talk@luv.asn.au> To: luv-talk@luv.asn.au Subject: [luv-talk] How many Lumens can blind you? Date: Tue, 03 Jul 2018 03:45:18 +1000 https://en.wikipedia.org/wiki/Lumen_(unit) _______________________________________________ luv-talk mailing list luv-talk@luv.asn.au https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-talk
It's also important to note that it's not only visible light that can harm, with lasers and other devices cable of generating wavelengths outside of the visible spectrum that nonetheless can damage the eye. Where light sources aren't visible, the usual safety instincts may not kick in (which is why it's always important to wear suitable eye protection when dealing with devices such as lasers). Even where instincts do kick in, they're not foolproof. On Tue, Jul 3, 2018 at 5:57 AM Lindsay W via luv-talk <luv-talk@luv.asn.au> wrote:
I am curios to find out why you wish to know this. The eye has a remarkable ability to recover from bright light source so to damage the retina enough to achieve total blindness one would need to look into a bright light source (such as an arc light at close range) for quite while, and this is likely to take a lot of will power. And believe me there is a distinct such an injury is VERY likely to be EXTREMELY painfull. DEFINITELY NOT RECOMMENDED.
Lindsay
----- Original message ----- From: "David Turk via luv-talk" <luv-talk@luv.asn.au> To: luv-talk@luv.asn.au Subject: [luv-talk] How many Lumens can blind you? Date: Tue, 03 Jul 2018 03:45:18 +1000
https://what-if.xkcd.com/73/ On Tue, 3 Jul 2018 at 12:53, Anthony via luv-talk <luv-talk@luv.asn.au> wrote:
It's also important to note that it's not only visible light that can harm, with lasers and other devices cable of generating wavelengths outside of the visible spectrum that nonetheless can damage the eye.
Where light sources aren't visible, the usual safety instincts may not kick in (which is why it's always important to wear suitable eye protection when dealing with devices such as lasers). Even where instincts do kick in, they're not foolproof.
On Tue, Jul 3, 2018 at 5:57 AM Lindsay W via luv-talk <luv-talk@luv.asn.au> wrote:
I am curios to find out why you wish to know this. The eye has a remarkable ability to recover from bright light source so to damage the retina enough to achieve total blindness one would need to look into a bright light source (such as an arc light at close range) for quite while, and this is likely to take a lot of will power. And believe me there is a distinct such an injury is VERY likely to be EXTREMELY painfull. DEFINITELY NOT RECOMMENDED.
Lindsay
----- Original message ----- From: "David Turk via luv-talk" <luv-talk@luv.asn.au> To: luv-talk@luv.asn.au Subject: [luv-talk] How many Lumens can blind you? Date: Tue, 03 Jul 2018 03:45:18 +1000
_______________________________________________ luv-talk mailing list luv-talk@luv.asn.au https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-talk
-- Dr Paul van den Bergen
On Tuesday, 3 July 2018 12:53:14 PM AEST Anthony via luv-talk wrote:
Where light sources aren't visible, the usual safety instincts may not kick in (which is why it's always important to wear suitable eye protection when dealing with devices such as lasers). Even where instincts do kick in, they're not foolproof.
One of the Tom Clancy books features CIA agents downing a Japanese military aircraft by shining a bright light at the pilots. Some people have suggested that a better option for the CIA agents in that scenario would be to use an IR LASER to blind pilots without them even noticing the light (which of course gives the difficult problem of how to line up an invisible LASER with a tiny target at a distance). It's probably best that Tom Clancy used a less effective way of downing an airline given that terrorists have already copied one of his ideas. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/
Russell Coker via luv-talk wrote:
On Tuesday, 3 July 2018 12:53:14 PM AEST Anthony via luv-talk wrote:
Where light sources aren't visible, the usual safety instincts may not kick in (which is why it's always important to wear suitable eye protection when dealing with devices such as lasers). Even where instincts do kick in, they're not foolproof.
One of the Tom Clancy books features CIA agents downing a Japanese military aircraft by shining a bright light at the pilots. Some people have suggested that a better option for the CIA agents in that scenario would be to use an IR LASER to blind pilots without them even noticing the light (which of course gives the difficult problem of how to line up an invisible LASER with a tiny target at a distance).
Maybe handheld devices can't be aimed that well, but: https://en.wikipedia.org/wiki/Boeing_YAL-1 It was a 747 with an --- as they say --- "frickin laser beam attached to its head", and it lased ballistic missiles, and it was a Real Thing. (I think it was defunded because the USA only attacks poor people, who can't afford the expensive toys YAL-1 was designed to counter.) Note the independent target-painting laser. One of AQ's publications suggested putting broken glass on your (flattish) roof, to confuse UAV/UCAV drones optics. I can't offhand think of anything interesting in between those two extremes... logically some active jammers ought to work in the manner you describe, but on the aircraft ELINT rather than the Mk. I eyeball. Oh, also, ASW searchlights were A Thing, although I think they couldn't be "aimed" independently of the aircraft's axis of travel. https://en.wikipedia.org/wiki/Leigh_light Oh, double-also, aiming a laser is in principle _easier_ than normal, because you don't have to lead the target. If the rangefinder is correctly zeroed, you point the weapon system straight at the target. Keeping it there is presumably equivalent to using a first-generation MANPAD. (I haven't read any FMs for those, so that's just speculation.) I think the real issue with accuracy would be relative to the size of the beam -- if it's 10 metres across at the target, and you're pointing it at a JASDF UH-60 that's debarking troops 600m away, it's should be feasible. If OTOH you're trying to hit an orbiting E-2 (AWACS) on the other side of Mt. Fuji and the beam is 10cm across... (https://en.wikipedia.org/wiki/JASDF#Current_inventory) For comparison, M24 acceptance requires 0.8 MOA, which translates to reliably hitting about a 2.3cm target at 100m. I dunno how to math that out to 600m range, but I guess it'd be about man-sized, so if your beam is that wide, at that distance, a trained human should be able to keep it on-target. (As opposed to their arm muscles making it wobble too much.)
If one has a GOOD rifle (solidly and evenly built, manually operated front locking bolt etc, NOT any automatic weapons) one will have little difficulty in landing successive shots in a 1 cm square at 100 metres BUT both the rifle AND the shooter him/her self needs to be WELL supported. If some one is shooting at you it would be quite safe to say one would NOT be able to hold a bead on someone for ANY length of time. Thats why automatic weapons were invented, they are designed to spray the landscape with fast flying solid objects. Note: It would be safe to say nearly all current armies will have snipers, single soldiers or small groups with some kind manually operated rifle, the US army sniper rifle is a nice weapon using standard 1/2inch ammunition accurate out to well over 1000 metres. For comparison, M24 acceptance requires 0.8 MOA, which translates to reliably hitting about a 2.3cm target at 100m. I dunno how to math that out to 600m range, but I guess it'd be about man-sized, so if your beam is that wide, at that distance, a trained human should be able to keep it on-target. (As opposed to their arm muscles making it wobble too much.) _______________________________________________ luv-talk mailing list luv-talk@luv.asn.au https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-talk
Lindsay W via luv-talk wrote:
If one has a GOOD rifle (solidly and evenly built, manually operated front locking bolt etc, NOT any automatic weapons) one will have little difficulty in landing successive shots in a 1 cm square at 100 metres BUT both the rifle AND the shooter him/her self needs to be WELL supported.
Ah, apologies, I was working from the example numbers in the https://en.wikipedia.org/wiki/Arcminute article. I see much smaller numbers on https://en.wikipedia.org/wiki/M24_Sniper_Weapon_System#Specifications
If some one is shooting at you it would be quite safe to say one would NOT be able to hold a bead on someone for ANY length of time. That's why automatic weapons were invented, they are designed to spray the landscape with fast flying solid objects.
Dr. Gatling wrote that he created [the Gatling gun] to reduce the size of armies and so reduce the number of deaths by combat and disease, and to show how futile war is.^[7] … It was not a true automatic weapon. The Maxim gun, invented and patented in 1883, was the first true fully automatic weapon. https://en.wikipedia.org/wiki/Gatling More a publicity stunt than a serious military contribution, in view of the main financier of the expedition, William Mackinnon, "merely exhibiting" the gun was likely to "prove a great peace-preserver".^[6] … It has been called "the weapon most associated with the British imperial conquest",^[2] https://en.wikipedia.org/wiki/Maxim_gun I guess you are thinking of suppressing fire doctrine by an integrated squad automatic rifleman, which is still aimed and is still fired in bursts of 5 to 8 rounds, in the last FM I read (to conserve ammo, and maximize time between barrel changes). IIRC the M240 requires a barrel change every 2 to 5 minutes depending on the rate of fire, and the operators between them only carry 2 spare barrels (and you can't safely swap barrels between M240s without a trip to the armourer). That's for air-cooled systems; automatic rifles that are not man-portable can use water cooling (water is heavy!) which can significantly lengthen time between barrel changes. Some man-portable automatic rifles are also capable of indirect fire, but I think this is rarely used in practice. Oh, I've been assuming you mean "automatic" in the sense of "fully automatic" rather than "semi-automatic" (self-loading).
the US army sniper rifle is a nice weapon using standard 1/2inch ammunition accurate out to well over 1000 metres.
https://en.wikipedia.org/wiki/List_of_equipment_of_the_United_States_Army#Sm... They field several sniper rifles (inc. "designated marksman" rifles, which is the anglicized term for soviet-style integrated sniper doctrine). I guess you're referring to the .50 BMG cartridge (originally for the M2 Browning, emphatically NOT a sniper rifle), which would therefore be the Barrett M82 (a.k.a. M107). AFAIK its main job is to kill engine blocks, not people. Also note that the above page is for the US Army specifically, not the US armed forces in general. See also https://en.wikipedia.org/wiki/Equipment_of_the_US_Navy#Small_Arms https://en.wikipedia.org/wiki/List_of_weapons_of_the_United_States_Marine_Co... https://en.wikipedia.org/wiki/List_of_individual_weapons_of_the_U.S._Armed_F... https://en.wikipedia.org/wiki/List_of_individual_weapons_of_the_U.S._Armed_F... Can't find one for the USAF.
My information comes from my own experience with fire arms, I regard any self loading rifle as "automatic". My own esperience is of course limited but I have fired a number of .243 calibre rifles, a number of .270's including a self loader, a 400 nitro express, .458 Bruno Magnum, a .457 or .458 Weatherby Magum and I have seen a M107 being fired. Note: One has to be EXTREMELY carefull with these latter 2 weapons as they will put a bullet completely intact through a 70cm hardwood tree even at 200 metres. The problem with getting fire arms REALLY accurate (all bullets landing in 1 cm square at 100metres) is that the mechanism CANNOT be allowed to distort unevenly. In high powered weapons on firing the chamber pressure is so high that it will cause the barrel to "balloon" slightly and if the bolt or the barrel is even slightly unevenly made, it will cause the barrel to deflect off straight. For this reason a group from a weapon such as the M107 it would be good going to land 5 shots in a 5cm circle. A problem with self loading (semi automatic) weapons is its very difficult to build them SIMPLE ,RELIABLE AND make the weapon accurate. With something like the M107 or the Weatherby one would have a reasonably good chance of killing a person at 1000 metres even if they were behind 20mm armour plate., hence the M107's use as a sniper rifle. To achieve this though you DO have take EXTREME care with the aimimg of the weapon. Lindsay ----- Original message ----- From: "Trent W. Buck" <trentbuck@gmail.com> To: Lindsay W <lindz_wolf@fastmail.com> Cc: luv-talk@luv.asn.au Subject: Re: [luv-talk] How many Lumens can blind you? Date: Tue, 10 Jul 2018 11:09:38 +1000 Lindsay W via luv-talk wrote:
If one has a GOOD rifle (solidly and evenly built, manually operated front locking bolt etc, NOT any automatic weapons) one will have little difficulty in landing successive shots in a 1 cm square at 100 metres BUT both the rifle AND the shooter him/her self needs to be WELL supported.
Ah, apologies, I was working from the example numbers in the https://en.wikipedia.org/wiki/Arcminute article. I see much smaller numbers on https://en.wikipedia.org/wiki/M24_Sniper_Weapon_System#Specifications
If some one is shooting at you it would be quite safe to say one would NOT be able to hold a bead on someone for ANY length of time. That's why automatic weapons were invented, they are designed to spray the landscape with fast flying solid objects.
Dr. Gatling wrote that he created [the Gatling gun] to reduce the size of armies and so reduce the number of deaths by combat and disease, and to show how futile war is.^[7] … It was not a true automatic weapon. The Maxim gun, invented and patented in 1883, was the first true fully automatic weapon. https://en.wikipedia.org/wiki/Gatling More a publicity stunt than a serious military contribution, in view of the main financier of the expedition, William Mackinnon, "merely exhibiting" the gun was likely to "prove a great peace-preserver".^[6] … It has been called "the weapon most associated with the British imperial conquest",^[2] https://en.wikipedia.org/wiki/Maxim_gun I guess you are thinking of suppressing fire doctrine by an integrated squad automatic rifleman, which is still aimed and is still fired in bursts of 5 to 8 rounds, in the last FM I read (to conserve ammo, and maximize time between barrel changes). IIRC the M240 requires a barrel change every 2 to 5 minutes depending on the rate of fire, and the operators between them only carry 2 spare barrels (and you can't safely swap barrels between M240s without a trip to the armourer). That's for air-cooled systems; automatic rifles that are not man-portable can use water cooling (water is heavy!) which can significantly lengthen time between barrel changes. Some man-portable automatic rifles are also capable of indirect fire, but I think this is rarely used in practice. Oh, I've been assuming you mean "automatic" in the sense of "fully automatic" rather than "semi-automatic" (self-loading).
the US army sniper rifle is a nice weapon using standard 1/2inch ammunition accurate out to well over 1000 metres.
https://en.wikipedia.org/wiki/List_of_equipment_of_the_United_States_Army#Sm... They field several sniper rifles (inc. "designated marksman" rifles, which is the anglicized term for soviet-style integrated sniper doctrine). I guess you're referring to the .50 BMG cartridge (originally for the M2 Browning, emphatically NOT a sniper rifle), which would therefore be the Barrett M82 (a.k.a. M107). AFAIK its main job is to kill engine blocks, not people. Also note that the above page is for the US Army specifically, not the US armed forces in general. See also https://en.wikipedia.org/wiki/Equipment_of_the_US_Navy#Small_Arms https://en.wikipedia.org/wiki/List_of_weapons_of_the_United_States_Marine_Co... https://en.wikipedia.org/wiki/List_of_individual_weapons_of_the_U.S._Armed_F... https://en.wikipedia.org/wiki/List_of_individual_weapons_of_the_U.S._Armed_F... Can't find one for the USAF.
Lindsay W wrote:
If one has a GOOD rifle (solidly and evenly built, manually operated front locking bolt etc, NOT any automatic weapons) … … Oh, I've been assuming you mean "automatic" in the sense of "fully automatic" rather than "semi-automatic" (self-loading). I regard any self loading rifle as "automatic".
Righto; I was reading it in a different context :-) You might like this falling-block single-shot bullpup: http://www.favsarmi.com/1/upload/cat_pagine_interne.jpg
The problem with getting fire arms REALLY accurate (all bullets landing in 1 cm square at 100metres) is that the mechanism CANNOT be allowed to distort unevenly. In high powered weapons on firing the chamber pressure is so high that it will cause the barrel to "balloon" slightly and if the bolt or the barrel is even slightly unevenly made, it will cause the barrel to deflect off straight. For this reason a group from a weapon such as the M107 it would be good going to land 5 shots in a 5cm circle.
The other way to mitigate that is to switch to a sabot cartridge (and a smoothbore barrel), which is what all main battle tanks do now (except for UK, for backcompat with special purpose rounds).
A problem with self loading (semi automatic) weapons is its very difficult to build them SIMPLE, RELIABLE AND make the weapon accurate.
Yep, granted — tradeoff of ROF vs. simplicity/reliability/accuracy. As a friend of mine once observed: if you need a semi-auto hunting rifle, you're hunting wrong. (You mentioned .700 Nitro Express and .50 BMG, though, which are overkill for anything but big game.)
With something like the M107 or the Weatherby one would have a reasonably good chance of killing a person at 1000 metres even if they were behind 20mm armour plate, hence the M107's use as a sniper rifle.
AFAIK this is not a common operational requirement. The current generation of the R700 / M24 family is effective up to 1200m (up from 800m): https://en.wikipedia.org/wiki/M2010_Enhanced_Sniper_Rifle AFAIK, * US snipers field the Remington 700 family when they expect to kill people * US snipers field the Barrett M82 family (i.e. M107) when they expect to kill light vehicles * US DMs field accurized semi-automatics from AR-15 or M14 families (branch-dependent) However I haven't found any specific citations to back up this rule of thumb. https://en.wikipedia.org/wiki/Anti-materiel_rifle#List_of_anti-materiel_rifl...
----- Original message ----- From: "Trent W. Buck" <trentbuck@gmail.com> To: Lindsay W <lindz_wolf@fastmail.com> Cc: luv-talk@luv.asn.au Subject: Re: [luv-talk] How many Lumens can blind you? Date: Tue, 10 Jul 2018 19:46:07 +1000 Lindsay W wrote:
If one has a GOOD rifle (solidly and evenly built, manually operated front locking bolt etc, NOT any automatic weapons) … … Oh, I've been assuming you mean "automatic" in the sense of "fully automatic" rather than "semi-automatic" (self-loading). I regard any self loading rifle as "automatic".
Righto; I was reading it in a different context :-)
The problem with getting fire arms REALLY accurate (all bullets landing in 1 cm square at 100metres) is that the mechanism CANNOT be allowed to distort unevenly. In high powered weapons on firing the chamber pressure is so high that it will cause the barrel to "balloon" slightly and if the bolt or the barrel is even slightly unevenly made, it will cause the barrel to deflect off straight. For this reason a group from a weapon such as the M107 it would be good going to land 5 shots in a 5cm circle.
The other way to mitigate that is to switch to a sabot cartridge (and a smoothbore barrel), which is what all main battle tanks do now (except for UK, for backcompat with special purpose rounds).
That will not get around the problem of non symetrical breach locking and Barrel IF anything is non symetrical the whole weapon will distort when its is fired with a consequent loss of accuracy.
A problem with self loading (semi automatic) weapons is its very difficult to build them SIMPLE, RELIABLE AND make the weapon accurate.
Yep, granted — tradeoff of ROF vs. simplicity/reliability/accuracy.
As a friend of mine once observed: if you need a semi-auto hunting rifle, you're hunting wrong.
Absolutely
(You mentioned .700 Nitro Express and .50 BMG, though, which are overkill for anything but big game.)
It was a 400 nitro express, used in tiger hunting and it gave the tiger a sporting chance as only an accurate shot would stop a tiger. VERY nice double rifle, made around 1895, the engraving on it was something one had to see to be believed. Kicks like a mule when fired as its quite light in weight, as does any .458 rifle and the M107.
With something like the M107 or the Weatherby one would have a reasonably good chance of killing a person at 1000 metres even if they were behind 20mm armour plate, hence the M107's use as a sniper rifle.
AFAIK this is not a common operational requirement.
Such operations were usually VERY secret to even well after the conflict had ended.
The current generation of the R700 / M24 family is effective up to 1200m (up from 800m): https://en.wikipedia.org/wiki/M2010_Enhanced_Sniper_Rifle
AFAIK,
* US snipers field the Remington 700 family when they expect to kill people * US snipers field the Barrett M82 family (i.e. M107) when they expect to kill light vehicles * US DMs field accurized semi-automatics from AR-15 or M14 families (branch-dependent)
However I haven't found any specific citations to back up this rule of thumb.
https://en.wikipedia.org/wiki/Anti-materiel_rifle#List_of_anti-materiel_rifl...
I think you will find the choice of weapon would have/still is the choice of the individual concerned, as REALLY accurate shooting is a combination of an exellent weapon and a VERY good operator. It being IMPOSSIBLE to get a poorly constucted rifle (and this would be most of them) to shoot straight. Lindsay
On Tuesday, 10 July 2018 3:19:48 AM AEST Trent W. Buck via luv-talk wrote:
Maybe handheld devices can't be aimed that well, but:
https://en.wikipedia.org/wiki/Boeing_YAL-1
It was a 747 with an --- as they say --- "frickin laser beam attached to its head", and it lased ballistic missiles, and it was a Real Thing.
(I think it was defunded because the USA only attacks poor people, who can't afford the expensive toys YAL-1 was designed to counter.)
The Wikipedia page quotes the SecDef as citing the fact that it is designed to target the boost phase and therefore can only be used near the launch site. That would require more than a few of them to cover the Middle East, North Korea, and wherever else trouble might come from. Also they wouldn't be able to do anything about submarine launched missiles so it would be a lot of expense for less effective results.
Oh, also, ASW searchlights were A Thing, although I think they couldn't be "aimed" independently of the aircraft's axis of travel. https://en.wikipedia.org/wiki/Leigh_light
That's interesting. I wasn't even aware that there was a minimum distance for radar before reading that.
For comparison, M24 acceptance requires 0.8 MOA, which translates to reliably hitting about a 2.3cm target at 100m. I dunno how to math that out to 600m range, but I guess it'd be about man-sized, so if your beam is that wide, at that distance, a trained human should be able to keep it on-target. (As opposed to their arm muscles making it wobble too much.)
Apparently a battery powered LASER pointer can burn a hole in the retina almost immediately if operating outside of Australian safety standards (people have been hospitalised for this). If you were designing a LASER weapon you wouldn't use hearing-aid batteries or AAA, you would use something a lot bigger. A 6V lantern battery would provide a lot more power while still fitting into a jacket pocket and a car battery wouldn't be ruled out for a portable weapon system (soldiers carry heavier things as parts of weapons). A quick scan of Wikipedia suggests that something less than 1W/cm^2 can give a 50% chance of damage in a millisecond for some frequencies. A 2.3cm target at 100m would be a 13.8cm target at 600m which is about 150cm^2. So 150W of LASER light (a small fraction of the power a car battery can provide even when considering LASER inefficiencies) would allow serious eye injury (maybe not permanent but definitely enough to stop someone flying a plane) in 1ms. To make an effective weapon you would probably want more power and a wider beam so that accurate aim is not required. Also with a 1ms damage time it shouldn't be difficult for the soldier to just wave it around until it gets a hit, should be much easier than aiming a machine gun. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/
Russell Coker wrote:
Apparently a battery powered LASER pointer can burn a hole in the retina almost immediately if operating outside of Australian safety standards (people have been hospitalised for this). If you were designing a LASER weapon you wouldn't use hearing-aid batteries or AAA, you would use something a lot bigger. A 6V lantern battery would provide a lot more power while still fitting into a jacket pocket and a car battery wouldn't be ruled out for a portable weapon system (soldiers carry heavier things as parts of weapons).
As a quick comparison, * an infantry rifle (to kill humans) weighs around 2.5kg to 4kg, plus ammo (3 to 6 magazines). * an M72 LAW (to kill light armor) weighs 2.5kg/shot * an 9K38 Igla (to kill helicopters) weighs 11kg + 1kg/shot * a FIM-92 Stinger (to kill helicopters) weighs 15kg + 3kg/shot * an FGM-148 Javelin (to kill heavy armor) weighs 22kg + -6kg/extra shot So if your goal is to kill an helicopter, your target weight is around 10kg for the complete unit. The FGM-148 includes lasers, but it's primarily infrared-guided (heat-seeking). An actual fielded laser for laser-guided is the AN/PED-1 LLDR, but I can't see how heavy that is: https://en.wikipedia.org/wiki/Laser_designator#Ground-based The AN/PEQ-2 and AN/PEQ-5 (rifle) and AN/PEQ-6 (pistol) are fielded lasers used for aiming and to designate targets to other infantry. They attach to the existing infantry rifle/pistol, so they probably weigh much less than 1kg. I think they are powered by AA or AAA batteries. Looking at their homepage, I can see actual target designators (as opposed to aiming devices): http://www.insighttechnology.com/l3-products/scarab-ground-laser-target-desi... https://www2.l3t.com/alst/products/r_multi_function_laser_systems.htm https://www2.l3t.com/alst/pdfs/datasheets/SCARAB-TILD-A.pdf That says the unit is 12kg. Someone who understands optics better than me can work out whether it's viable for shooting out the eyeballs of enemy pilots. Oh, PS, a lead-acid car battery apparently weighs somewhere between 6kg and 25kg.
A quick scan of Wikipedia suggests that something less than 1W/cm^2 can give a 50% chance of damage in a millisecond for some frequencies. A 2.3cm target at 100m would be a 13.8cm target at 600m which is about 150cm^2. So 150W of LASER light (a small fraction of the power a car battery can provide even when considering LASER inefficiencies) would allow serious eye injury (maybe not permanent but definitely enough to stop someone flying a plane) in 1ms. To make an effective weapon you would probably want more power and a wider beam so that accurate aim is not required. Also with a 1ms damage time it shouldn't be difficult for the soldier to just wave it around until it gets a hit, should be much easier than aiming a machine gun.
A couple of random comments, A human eye at a distance of 1000 metres represents an angular error of aprox 1 in 10000. In current military hardware its VERY unlikley that a gun mount or radar that could track to that accuracy. Artillary not usually requiring an angular accuracy of greater then around 1 in 1 or 2000. Becasue of radar's inabilty track any flying target very acurately nearly all current anti aircraft use blast fragmentation warheads using proximity fusing. These do NOT need to hit a target, the war head on detonating throwing out thousands of pieces of shrapnel in all directions. Any laser weapon would be a line of site weapon and would be in a position where they would be seen, very likley making them EXTREMELY vulnerable to artillary. Nearly all ground attack is these days done by helicopters, due to the amount of fire power infantary now have, these aircraft operate via stealth. There siting systems being usually above the rotar so any target can be sited and attacked from behind cover, such an aircraft would not be vulnerable to lasers. Unlike normal weapons its relatively easy to develop excellent shielding systems to any light driven weapon systems simply using reflective material. LIndsay
given how far off topic this has gone, I refer you to the Casaba Howitzer... http://toughsf.blogspot.com/2016/06/the-nuclear-spear-casaba-howitzer.html On Tue, 17 Jul 2018 at 00:41, Lindsay W via luv-talk <luv-talk@luv.asn.au> wrote:
A couple of random comments,
A human eye at a distance of 1000 metres represents an angular error of aprox 1 in 10000. In current military hardware its VERY unlikley that a gun mount or radar that could track to that accuracy. Artillary not usually requiring an angular accuracy of greater then around 1 in 1 or 2000.
Becasue of radar's inabilty track any flying target very acurately nearly all current anti aircraft use blast fragmentation warheads using proximity fusing. These do NOT need to hit a target, the war head on detonating throwing out thousands of pieces of shrapnel in all directions.
Any laser weapon would be a line of site weapon and would be in a position where they would be seen, very likley making them EXTREMELY vulnerable to artillary.
Nearly all ground attack is these days done by helicopters, due to the amount of fire power infantary now have, these aircraft operate via stealth. There siting systems being usually above the rotar so any target can be sited and attacked from behind cover, such an aircraft would not be vulnerable to lasers.
Unlike normal weapons its relatively easy to develop excellent shielding systems to any light driven weapon systems simply using reflective material.
LIndsay _______________________________________________ luv-talk mailing list luv-talk@luv.asn.au https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-talk
-- Dr Paul van den Bergen
Lindsay W via luv-talk wrote:
Unlike normal weapons its relatively easy to develop excellent shielding systems to any light driven weapon systems simply using reflective material.
The other active defense I've seen against proposed in-atmosphere DEWs is simply to spray a mist of water into the air. :-) (That's for ships, rather than individual soldiers; water is heavy.) I couldn't find a cite for it, but I did find this one: There are reports that the Terra-3 complex at Sary Shagan was used on several occasions to temporarily "blind" US spy satellites in the IR range. https://en.wikipedia.org/wiki/Directed_energy_weapons#Alleged_tracking_of_Sp... So at least the Russians have uses lasers to shoot the eyes out of something moving much faster than a mere fighter jet ;-P
Russell Coker via luv-talk wrote:
One of the Tom Clancy books features CIA agents downing a Japanese military aircraft by shining a bright light at the pilots. [...] It's probably best that Tom Clancy used a less effective way of downing an airline given that terrorists have already copied one of his ideas.
PS: terrorists don't need Tom Clancy's CIA to give them ideas; the *ACTUAL* CIA will come around to their house and train them, for free. Start from https://en.wikipedia.org/wiki/CIA#1953_Iranian_coup_d'état and look at all the mentions of "train".
On Tuesday, 10 July 2018 3:33:52 AM AEST Trent W. Buck via luv-talk wrote:
Russell Coker via luv-talk wrote:
One of the Tom Clancy books features CIA agents downing a Japanese military aircraft by shining a bright light at the pilots. [...] It's probably best that Tom Clancy used a less effective way of downing an airline given that terrorists have already copied one of his ideas.
PS: terrorists don't need Tom Clancy's CIA to give them ideas; the *ACTUAL* CIA will come around to their house and train them, for free.
;)
Start from https://en.wikipedia.org/wiki/CIA#1953_Iranian_coup_d'état and look at all the mentions of "train".
But I don't think the CIA had the idea of using a heavy passenger jet as a missile. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/
Quoting russell@coker.com.au (russell@coker.com.au):
But I don't think the CIA had the idea of using a heavy passenger jet as a missile.
On the other hand, the writers of the March 2001 pilot episode of 'The Lone Gunmen' did. (This was just a spooky coincidence, but really bothered the writers until that fact was proven.) https://www.scpr.org/news/2015/03/24/50548/the-x-files-mulder-and-scully-wil... Another odd fact: My father, Pan American World Airways Captain Arthur Moen, kept advising his employer and the Federal Aviation Administration in the 1960s that they could put a screeching halt to airline hijackings by simply reinforcing the door to the flight deck. They never did - until the 2000s. (Dad himself never lived to see them taking his advice, having been killed by a defective B-707 in 1968.)
Rick Moen via luv-talk wrote:
Quoting russell@coker.com.au (russell@coker.com.au):
I don't think the CIA had the idea of using a heavy passenger jet as a missile.
My father […] kept advising his employer and the FAA in the 1960s that they could put a screeching halt to airline hijackings by simply reinforcing the door to the flight deck. They never did– until the 2000s.
Are (light) aircraft often left in unlocked hangars "with fuel in the tank and keys in the ignition"? ISTR Bruce Schneier saying something along those lines, way back when. My impression was that they (aircraft owners & airport operators) basically relied on there being very few many people who can fly AND want to fence a stolen vehicle for a bag of smack. PS: yes, obviously a little airframe with 2hr of fuel in its tanks will make a much smaller boom than a big airframe with 20hr of fuel in its tanks, and obviously you'd have to train the rebels in how to fly the aircraft, instead of them just putting a sharp pencil in the regular pilot's ear and threatening to push it in.
----- Original message ----- From: "Trent W. Buck via luv-talk" <luv-talk@luv.asn.au> To: Rick Moen <rick@linuxmafia.com> Cc: luv-talk@luv.asn.au Subject: Re: [luv-talk] How many Lumens can blind you? Date: Mon, 16 Jul 2018 14:04:35 +1000
Rick Moen via luv-talk wrote:
Quoting russell@coker.com.au (russell@coker.com.au):
I don't think the CIA had the idea of using a heavy passenger jet as a missile.
My father […] kept advising his employer and the FAA in the 1960s that they could put a screeching halt to airline hijackings by simply reinforcing the door to the flight deck. They never did– until the 2000s.
Are (light) aircraft often left in unlocked hangars "with fuel in the tank and keys in the ignition"?
ISTR Bruce Schneier saying something along those lines, way back when.
My impression was that they (aircraft owners & airport operators) basically relied on there being very few many people who can fly AND want to fence a stolen vehicle for a bag of smack.
A couple of points for the discusion....... The keys to a light aircraft (including aircraft such as the Beechcraft Baron) are NOT the security system they are in modern cars all the key switch does is act as a sort of master power switch. The ignition for the engine/engines being controled be separate switchs on the panel, either 2 toggle switchs marked "A" and "B" or a rotary switch marked "Off, A, B, both". So the key switch cannot usually disable the engine/engines. Also given the fact that in ALL aircraft there is a comprehensive relatively easy to access circuit breaker panel covering all systems in the aircraft, it would not be to difficult to "hot wire" any system required for a flight. General aviation aircraft are usually left with full tanks, the reason for this is if the tanks are left empty, it is possible for the moisture in the air in an empty tank to condense into a liquid and cause a possible engine failure in the next flight. While it is required in the initial aircraft inpsection to drain a portion of the fuel from every tank in the aircraft to check for water, experience shows this test is NOT 100% reliable. Lindsay
Quoting Trent W. Buck (trentbuck@gmail.com):
Are (light) aircraft often left in unlocked hangars "with fuel in the tank and keys in the ignition"?
ISTR Bruce Schneier saying something along those lines, way back when.
What I don't know about general aviation would fill libraries, sorry. (After my father's demise, I carefully avoided having much to do with small aircraft, to make my mother worry less.) My guess is that security for small planes tends, indeed, to be pretty lax. But they're also pretty slow and have little momentum or fuel capacity, so their potential as weapons is a great deal less.
On Monday, 16 July 2018 4:45:46 PM AEST Rick Moen via luv-talk wrote:
Quoting Trent W. Buck (trentbuck@gmail.com):
Are (light) aircraft often left in unlocked hangars "with fuel in the tank and keys in the ignition"?
ISTR Bruce Schneier saying something along those lines, way back when.
What I don't know about general aviation would fill libraries, sorry. (After my father's demise, I carefully avoided having much to do with small aircraft, to make my mother worry less.)
My guess is that security for small planes tends, indeed, to be pretty lax. But they're also pretty slow and have little momentum or fuel capacity, so their potential as weapons is a great deal less.
https://en.wikipedia.org/wiki/2010_Austin_suicide_attack I only know of one such terrorist attack, and that killed one person other than the terrorist and injured 13 others. It caused a significant amount of property damage, but driving a 4WD through a pedestrian area could kill more. Of course if he had flown his plane into a crowd (superbowl or something) there would have been many more deaths and injuries from the crash and more from the stampede. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/
Quoting Russell Coker (russell@coker.com.au):
Yes, I was thinking about that one, specifically, when I wrote the upthread posting. The Piper PA-28 Cherokee the attacker used (in that case) is fairly typically of general-aviation aircraft, massing 544 kg empty (975 kg fully loaded) with a maximum speed of 230 km/hr. A tonne traveling at 230 km/hr is certainly going to kill multiple people at the point of impact, but OTOH isn't likely to produce mass casualties _in general_. On the third (gripping[1]) hand, as you note:
Of course if he had flown his plane into a crowd (superbowl or something) there would have been many more deaths and injuries from the crash and more from the stampede.
Quite possibly. [1] In-joke for readers of Niven & Pournelle's _The Mote in God's Eye_ and its sequels.
Russell Coker via luv-talk wrote:
https://en.wikipedia.org/wiki/2010_Austin_suicide_attack […] driving a 4WD through a pedestrian area could kill more.
I started trying to get creative using the fuel tanks for a https://en.wikipedia.org/wiki/Fuel-air_explosive …but you're right, why bother? Kinetic strikes using an ordinary minivan are plenty good enough, and can be done by essentially unskilled labour on an ad-hoc basis, and tie up "the state" installing concrete bollards everywhere (sensible response) or for empire-building within the military-industrial complex (silly response).
On Tuesday, 24 July 2018 10:52:31 AM AEST Trent W. Buck via luv-talk wrote:
Russell Coker via luv-talk wrote:
https://en.wikipedia.org/wiki/2010_Austin_suicide_attack […] driving a 4WD through a pedestrian area could kill more.
I started trying to get creative using the fuel tanks for a https://en.wikipedia.org/wiki/Fuel-air_explosive …but you're right, why bother?
Kinetic strikes using an ordinary minivan are plenty good enough, and can be done by essentially unskilled labour on an ad-hoc basis, and tie up "the state" installing concrete bollards everywhere (sensible response) or for empire-building within the military-industrial complex (silly response).
https://en.wikipedia.org/wiki/December_2017_Melbourne_car_attack When you have millions of cars privately owned and lenient laws about driving without a license things like the above are pretty much impossible to prevent. One thing they could do is install bollards that raise from the ground when there's a red light. While it's not practical to try and install such bollards everywhere, if they were installed at the 20 intersections in the CBD with the most pedestrian traffic they could reduce the potential for harm. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/
On 25/07/2018 4:18 PM, Russell Coker via luv-talk wrote:
On Tuesday, 24 July 2018 10:52:31 AM AEST Trent W. Buck via luv-talk wrote:
Russell Coker via luv-talk wrote:
https://en.wikipedia.org/wiki/2010_Austin_suicide_attack […] driving a 4WD through a pedestrian area could kill more. I started trying to get creative using the fuel tanks for a https://en.wikipedia.org/wiki/Fuel-air_explosive …but you're right, why bother?
Kinetic strikes using an ordinary minivan are plenty good enough, and can be done by essentially unskilled labour on an ad-hoc basis, and tie up "the state" installing concrete bollards everywhere (sensible response) or for empire-building within the military-industrial complex (silly response). https://en.wikipedia.org/wiki/December_2017_Melbourne_car_attack
When you have millions of cars privately owned and lenient laws about driving without a license things like the above are pretty much impossible to prevent.
One thing they could do is install bollards that raise from the ground when there's a red light. While it's not practical to try and install such bollards everywhere, if they were installed at the 20 intersections in the CBD with the most pedestrian traffic they could reduce the potential for harm.
Until of course someone positions their baby's pram over the top of one of the retractedbollard while waiting for the lights to change. Cue Junior being launched on a ballistic arc in the general direction of the traffic stream. Unfortunately there's no such thing as "Stupid proof". Someone always invents a betterstupid. Regards, Morrie. (Wot! Me cynical?)
Retractable bollards have been in wide spread use in many countries for over 20 years. I haven't heard reports of such problems. Many cars have been damaged by trying to sneak over a bollard but I am not aware of human injuries. If you stand on a bollard while it's raising it doesn't cause any problems. On 25 July 2018 4:47:35 pm AEST, Morrie Wyatt via luv-talk <luv-talk@luv.asn.au> wrote:
On 25/07/2018 4:18 PM, Russell Coker via luv-talk wrote:
On Tuesday, 24 July 2018 10:52:31 AM AEST Trent W. Buck via luv-talk wrote:
Russell Coker via luv-talk wrote:
https://en.wikipedia.org/wiki/2010_Austin_suicide_attack […] driving a 4WD through a pedestrian area could kill more. I started trying to get creative using the fuel tanks for a https://en.wikipedia.org/wiki/Fuel-air_explosive …but you're right, why bother?
Kinetic strikes using an ordinary minivan are plenty good enough, and can be done by essentially unskilled labour on an ad-hoc basis, and tie up "the state" installing concrete bollards everywhere (sensible response) or for empire-building within the military-industrial complex (silly response). https://en.wikipedia.org/wiki/December_2017_Melbourne_car_attack
When you have millions of cars privately owned and lenient laws about driving without a license things like the above are pretty much impossible to prevent.
One thing they could do is install bollards that raise from the ground when there's a red light. While it's not practical to try and install such bollards everywhere, if they were installed at the 20 intersections in the CBD with the most pedestrian traffic they could reduce the potential for harm.
Until of course someone positions their baby's pram over the top of one
of the retractedbollard while waiting for the lights to change.
Cue Junior being launched on a ballistic arc in the general direction of the traffic stream.
Unfortunately there's no such thing as "Stupid proof". Someone always invents a betterstupid.
Regards, Morrie.
(Wot! Me cynical?)
_______________________________________________ luv-talk mailing list luv-talk@luv.asn.au https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-talk
-- Sent from my Huawei Mate 9 with K-9 Mail.
Hi Russell. My comment was meant with a great deal of "tongue in cheek". (* Shock horror! You mean that Blazing Saddles wasn't a documentary? O:-)) The extension and retraction times for automatic bollards is quite leisurely to say the least. A quick Google search shows that the idea was considered, but rejected for the Bourke St. Mall, as the duty cycle to allow trams to pass was much too high. Timed with traffic lights would suffer from even higher duty cycles, and because these are either pneumatically, hydraulicly or motor driven, the operating and maintenance costs would be appreciable. It would be a bit like putting in railroad crossings at all of the intersections. Traffic would back up severely at these intersections, just as it does with railroad crossings in peak hour. And also like railroad crossings, there would be a those idiots that would find themselves atop the bollards when the lights changed. And let's face it, we are talking about the same political leaders that tell us that the revised NBN is fit for purpose and future proof? In an old "B.C." comic, Wiley's Dictionary described politics as: "A many handed game in which mud balls are trumps." I can't say I've ever found reason to disagree. Regards, Morrie. * Mel Brooks: Gentlemen. We need to protect our phoney baloney jobs! On 25/07/2018 7:44 PM, Russell Coker wrote:
Retractable bollards have been in wide spread use in many countries for over 20 years. I haven't heard reports of such problems. Many cars have been damaged by trying to sneak over a bollard but I am not aware of human injuries.
If you stand on a bollard while it's raising it doesn't cause any problems.
On 25 July 2018 4:47:35 pm AEST, Morrie Wyatt via luv-talk <luv-talk@luv.asn.au> wrote:
On 25/07/2018 4:18 PM, Russell Coker via luv-talk wrote:
On Tuesday, 24 July 2018 10:52:31 AM AEST Trent W. Buck via luv-talk wrote:
Russell Coker via luv-talk wrote:
https://en.wikipedia.org/wiki/2010_Austin_suicide_attack […] driving a 4WD through a pedestrian area could kill more. I started trying to get creative using the fuel tanks for a https://en.wikipedia.org/wiki/Fuel-air_explosive …but you're right, why bother?
Kinetic strikes using an ordinary minivan are plenty good enough, and can be done by essentially unskilled labour on an ad-hoc basis, and tie up "the state" installing concrete bollards everywhere (sensible response) or for empire-building within the military-industrial complex (silly response). https://en.wikipedia.org/wiki/December_2017_Melbourne_car_attack
When you have millions of cars privately owned and lenient laws about driving without a license things like the above are pretty much impossible to prevent. One thing they could do is install bollards that raise from the ground when there's a red light. While it's not practical to try and install such bollards everywhere, if they were installed at the 20 intersections in the CBD with the most pedestrian traffic they could reduce the potential for harm. Until of course someone positions their baby's pram over the top of one
of the retractedbollard while waiting for the lights to change.
Cue Junior being launched on a ballistic arc in the general direction of the traffic stream.
Unfortunately there's no such thing as "Stupid proof". Someone always invents a betterstupid.
Regards, Morrie.
(Wot! Me cynical?)
_______________________________________________ luv-talk mailing list luv-talk@luv.asn.au https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-talk
This one of the more serious problems in using energy beam weapons, one cannot tell if one misses a target by a centimetre or a kilometre. Where as one has no difficulty in tracking a missile or a shell. ----- Original message ----- From: "Russell Coker via luv-talk" <luv-talk@luv.asn.au> To: luv-talk@luv.asn.au Subject: Re: [luv-talk] How many Lumens can blind you? Date: Mon, 09 Jul 2018 23:43:45 +1000 On Tuesday, 3 July 2018 12:53:14 PM AEST Anthony via luv-talk wrote:
Where light sources aren't visible, the usual safety instincts may not kick in (which is why it's always important to wear suitable eye protection when dealing with devices such as lasers). Even where instincts do kick in, they're not foolproof.
One of the Tom Clancy books features CIA agents downing a Japanese military aircraft by shining a bright light at the pilots. Some people have suggested that a better option for the CIA agents in that scenario would be to use an IR LASER to blind pilots without them even noticing the light (which of course gives the difficult problem of how to line up an invisible LASER with a tiny target at a distance). It's probably best that Tom Clancy used a less effective way of downing an airline given that terrorists have already copied one of his ideas. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/ _______________________________________________ luv-talk mailing list luv-talk@luv.asn.au https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-talk
On Tuesday, 10 July 2018 7:52:49 AM AEST Lindsay W via luv-talk wrote:
This one of the more serious problems in using energy beam weapons, one cannot tell if one misses a target by a centimetre or a kilometre. Where as one has no difficulty in tracking a missile or a shell.
LASER light will exactly follow line of sight, including being refracted or reflected. If you see something and line a LASER on what you see then you will hit it. Unlike bullets which are diverted by wind that can't be seen and aren't diverted by optical effects. If you can see the frequence of your LASER then you will see some light reflected back to you from dust. For the distances over which hand-held LASERs are effective this does the job. For longer distances you could have a camera that reads IR (or whatever frequency isn't visible to humans) and has a display in frequencies a human can see. For autonomous weapon systems a beam weapon removes the need to predict the future position of the target and allows just tracking the current position. This should be useful for point-defence anti-missile systems. That said the US navy is apparently currently using rapid fire machine guns for such systems so they probably work. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/
On Tuesday, 3 July 2018 5:57:36 AM AEST Lindsay W via luv-talk wrote:
I am curios to find out why you wish to know this. The eye has a remarkable ability to recover from bright light source so to damage the retina enough to achieve total blindness one would need to look into a bright light source (such as an arc light at close range) for quite while, and this is likely to take a lot of will power. And believe me there is a distinct such an injury is VERY likely to be EXTREMELY painfull. DEFINITELY NOT RECOMMENDED.
To damage an area of the retina large enough to cause total blindness would take some time. To damage a small section that can significantly limit visition (especially if the victim looked at the source) would take much less time. Apparently a good portion of LASER pointers sold in Australia don't meet Australian safety standards and can vaporise a chunk of retina rapidly. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5754573/ The above link has a meta-study of LASER related eye injuries. https://www.scientificamerican.com/article/can-a-pocket-laser-damage/ The above is an article for people with less scientific background. It also has some helpful advice like "you shouldn't force a stare at a laser, just like you shouldn't stare at the sun or any bright light source" and "Do not shine it onto a mirror or mirror-like surface. Do not look at the beam through binoculars or a microscope". A final note, please be careful when making household pets chase the LASER dot. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/
participants (8)
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Anthony -
David Turk -
Lindsay W -
Morrie Wyatt -
Paul van den Bergen -
Rick Moen -
Russell Coker -
Trent W. Buck