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Different questions about the lasers

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val45130

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Jan 3, 2015
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Hello,

I'm totally a noob about the laser pointer
I wan't to buy a laser with a range of 5km in night. But I don't know what the power in need in mW for obtain this.
I've found a lots of website who they sell laser pointer but I'm pretty it's just 2mW, or simply the laser can not reach 5km.

I wan't to buy :

- Can reach 5km or more
- Purple or Green color

If it's possible not expensive, because I don't wan't a pointer for the professional.

Thank you in advance for your response and sorry for my English
 





val45130 said:
Hello,

I'm totally a noob about the laser pointer
I wan't to buy a laser with a range of 5km in night. But I don't know what the power in need in mW for obtain this.
I've found a lots of website who they sell laser pointer but I'm pretty it's just 2mW, or simply the laser can not reach 5km.

I wan't to buy :

- Can reach 5km or more
- Purple or Green color

If it's possible not expensive, because I don't wan't a pointer for the professional.

Thank you in advance for your response and sorry for my English
Click to expand...

If you want to see the beam itself, as opposed to the dot of light on your target...there are differences in what would work at 5 km.

For example, how big a dot could you SEE 5 km away?


Different colors (wavelengths) of light are easier, or harder, to see, than others.

Purple for example would be very very hard to see, but green, for the same mw, would be very easy to see.

So, to have the best chance of seeing it with a given power output, green would be FAR better than purple.


What's at 5 km that you are trying to see it hit? (And what color/reflectiveness of the background is there for contrast, etc?)


ALL lasers can project a beam 5 km...but, may not be bright enough to SEE depending on the circumstances.
 
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as Teej replied all laser go much further than we can see==what 'appears' to the eye to be the end on the beam is NOT correct.

many arrested in USA said they were only trying to 'see' how far their laser 'went by aiming at aircraft. duh!

Lasers have been seen by astronauts in space.

When you are on the 'other' end you will see more than from any other position.

on another note..
your thread has been placed in the wrong section, .....AND your first thread SHOULD have been a 'INTRO' of yourself and placed in the WELCOME section. while we do like to help we also like to see respect== you need to make that thread and also add MORE info in yr personal profile.
...manly your location==WHERE you are makes huge DIFF when it comes to advice..
and there is likely member or two close enough for hands-on help or to get a laser metered for free.


AND-- had you done some homework by searching you could have found your own answers.. we are NOT fond of answering the SAME questions over and over.
best place to buy his here in out BS&T section. (from another [vet] member)

hak
 
hakzaw1 said:
as Teej replied all laser go much further than we can see==what 'appears' to the eye to be the end on the beam is NOT correct.

many arrested in USA said they were only trying to 'see' how far their laser 'went by aiming at aircraft. duh!

Lasers have been seen by astronauts in space.

When you are on the 'other' end you will see more than from any other position.

on another note..
your thread has been placed in the wrong section, .....AND your first thread SHOULD have been a 'INTRO' of yourself and placed in the WELCOME section. while we do like to help we also like to see respect== you need to make that thread and also add MORE info in yr personal profile.
...manly your location==WHERE you are makes huge DIFF when it comes to advice..
and there is likely member or two close enough for hands-on help or to get a laser metered for free.


AND-- had you done some homework by searching you could have found your own answers.. we are NOT fond of answering the SAME questions over and over.
best place to buy his here in out BS&T section. (from another [vet] member)

hak
Click to expand...

Teej said:
If you want to see the beam itself, as opposed to the dot of light on your target...there are differences in what would work at 5 km.

For example, how big a dot could you SEE 5 km away?


Different colors (wavelengths) of light are easier, or harder, to see, than others.

Purple for example would be very very hard to see, but green, for the same mw, would be very easy to see.

So, to have the best chance of seeing it with a given power output, green would be FAR better than purple.


What's at 5 km that you are trying to see it hit? (And what color/reflectiveness of the background is there for contrast, etc?)


ALL lasers can project a beam 5 km...but, may not be bright enough to SEE depending on the circumstances.
Click to expand...

Thank you for your response.
I don't understand everything. But I wan't a laser can reach 5km in night with no rain, no fog...
I already see a laser like this, the guy use it for astronomy and some times he target a water tower, the laser hit the water tower and we see a green circle with the size of the water tower
 
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val45130 said:
Thank you for your response.
I don't understand everything. But I wan't a laser can reach 5km in night with no rain, no fog...
I already see a laser like this, the guy use it for astronomy and some times he target a water tower, the laser hit the water tower and we see a green circle with the size of the water tower
Click to expand...

So, you want to be able to see a green dot on a water tower 5 km away?

I'm a little confused about wording..."the size of the water tower" means that the "dot" is really big, the same size as the water tower?

What is that water tower's lit up size across/height....in meters?


Did you want a dot (normal laser effect), or to light up the entire water tower (Flashlight effect)?

That is your objective?
 
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Teej said:
Describe what you'd like it to do?
Click to expand...

Play with it, like a lots of person here. And also for use it in astronomy because I like the stars, and sometimes with friends I show where is this star, this star, constellation...
 
val45130 said:
Play with it, like a lots of person here. And also for use it in astronomy because I like the stars, and sometimes with friends I show where is this star, this star, constellation...
Click to expand...

I point out stars, etc, too, and, the green is very visible.

I use an 80 mw 532 nm for stars, which works very well.

I also use a 3 w 445 (Blue) which works even better, and I've been told it looks like the star is sitting on top of a blue column of light when pointed out with it.

The higher power lasers can overheat the diode if pointed for too long at a time, so I pace the "Points" to a few seconds at a time to help avoid that...and use more than one laser to allow me to alternate, etc.

The 80 mw 532 (Green) can be used to put a bright dot on the top of a skyscraper in broad daylight for example (Green is typically the most visible color for the same wattage)...but a 3 watt 445 (Blue) can light a cigarette 10' away, etc...and also put a bright blue dot on that skyscraper's top in broad daylight.

Those would be two examples at opposite ends of the cost/performance spectrum.



:D
 
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Teej said:
I point out stars, etc, too, and, the green is very visible.

I use an 80 mw 532 nm for stars, which works very well.

I also use a 3 w 445 (Blue) which works even better, and I've been told it looks like the star is sitting on top of a blue column of light when pointed out with it.

The higher power lasers can overheat the diode if pointed for too long at a time, so I pace the "Points" to a few seconds at a time to help avoid that...and use more than one laser to allow me to alternate, etc.

The 80 mw 532 (Green) can be used to put a bright dot on the top of a skyscraper in broad daylight for example (Green is typically the most visible color for the same wattage)...but a 3 watt 445 (Blue) can light a cigarette 10' away, etc...and also put a bright blue dot on that skyscraper's top in broad daylight.

:D
Click to expand...
So for me the best is 80mw 532 in green. Because I think the 3w is too expensive ?
 
val45130 said:
So for me the best is 80mw 532 in green. Because I think the 3w is too expensive ?
Click to expand...

I would get a 532 in as high a power as you could afford at least....I would not go lower than 80 mw myself based on my use at least.

I would also get it from someone here who makes them rather than from most ebay/amazon sources, etc...so that you could have confidence in what you get. (There's a lot of over priced junk out there...)

I'd also get safety goggles with the correct wavelength (including 532 nm) to help to avoid accidental eye damage from a reflection, etc. (Not needed for astronomy typically, but indoors, absolutely)

Read about the safety, avoiding aircraft/eyes, etc.

These also tend to use rechargeable lithium ion cells, and there are some things to read about them as well.

:D
 
Teej said:
I would get a 532 in as high a power as you could afford at least....I would not go lower than 80 mw myself based on my use at least.

I would also get it from someone here who makes them rather than from most ebay/amazon sources, etc...so that you could have confidence in what you get. (There's a lot of over priced junk out there...)

I'd also get safety goggles with the correct wavelength (including 532 nm) to help to avoid accidental eye damage from a reflection, etc. (Not needed for astronomy typically, but indoors, absolutely)

Read about the safety, avoiding aircraft/eyes, etc.

These also tend to use rechargeable lithium ion cells, and there are some things to read about them as well.

:D
Click to expand...

My friend know the rules about aiming the sky with a laser in France for the aircraft ;)
I found this on the forum, this guy make a lost of test :
http://laserpointerforums.com/f52/100mw-532nm-15-a-87292.html
A 100mW 532 (green) can be at 15$ ?
 
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val45130 said:
Ok going to see, but this laser is out of stock. I gonna search on another website.

Thank !
Click to expand...

Teen has pretty much summed it up well. I would like to add that a good rule of thumb for 532nm(Green) lasers is count around $1/per mW.

For example:
100mW=$100
250mW=$250

-Alex
 
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