# Can a green laser pointer with low power be used for star-pointing?



## ttvolcano

I am an astrophile and want a green laser for star-pointing. in photonlexicon forum, guys remind me that laser pointers with high power is dangerous and advise me to ask for opinoins in this forum. i find one with less power and much lower price 5mW 532nm Green Laser Pointer Pen compared with the previous one. but the point is if one with low power can be used for star-pointing. Is it bright enough or can it shot that far?


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## blasterman

They aren't dangerous. A 5mw green just has more potential for an idiot to be more of an idiot with one. 

Something in the 30-40mw range should be fine for star pointing. While 5mw can work for this, if it's a dry night the brighter pointer is more visible off axis.


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## bradsystem

hi ttvolcano,

i think low power laser is useless, it just make small green point around you, but makes nothing when you point to sky.
own a 700mw 532nm laser and using it for directing outdoor wifi antenas,
it makes nice green line between ap and client antenas, so i know where to direct antena exactly.
when you want to use it for astronomy then with such strong laser you will have nice star pointer,
you will have long line from your hand and everyone around you must know where you point at. 
about danger: yes its dangerous, you need to care to not light into your or anyone else eyes.
also can burn skin, if you point it to hand for example you will feel in 2-3seconds that your skin is hot and you will make "quick move" for sure..

so thats my opinion..

bRAd


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## blasterman

A 700mw green laser costs around ~$800? The common ones in the 30-60mw range about $25.


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## bshanahan14rulz

I'm with blasterman on this one. A 5mW laser you will often be able to see the beam, and if a person is lying on the ground right next to you, they might too, faintly. The benefit here is that it is a 5mW laser, which is safer. 
A 30mW laser will be a pretty good star pointer, are relatively cheap as well, and will still take common AAA or AA batteries. It is less safe, though. At that power level, your blink reflex will not be enough to save your retina should you accidentally take a direct or reflected hit to the eye.


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## 127.0.0.1

5mw is fine for astronomy, all you need is a beam that can be seen for about 100 feet and
my 5mw green can be seen for much further on clear nights

higher power is unsafe without protective glasses


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## subwoofer

127.0.0.1 said:


> 5mw is fine for astronomy, all you need is a beam that can be seen for about 100 feet and
> my 5mw green can be seen for much further on clear nights
> 
> higher power is unsafe without protective glasses






+1 on that. I have a 5mW green laser and it works perfectly for star pointing. Remember most observers will also have dark adapted eyes so pick up the beam easily.

I also have a 50mW which is very clear even without dark adapted eyes. This is more than enough, so anyone recommending more is giving you bad advice. A real 5mW is fine and much safer (though 5mW it is still strong enough to damage your eyesight if you get a direct blast).

Some of the cheaper 30mW and 50mW lasers I've seen have quite a wide (though well collimated) beam which seems to make it easier to see, but if you go over 5mW be very careful.


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## blasterman

My cat won't chase a 5mw, and many of the 5mw Greens are much more powerfull anyways but labeled that way to get past customs.

A true 5mw green requires you look right down the axis of the beam on a dry night. Not saying you need my 1watt 445.


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## Burgess

I use my 5mw Green laser pointer ALL THE TIME for star-pointing.

Admittedly, sometimes i need to be *In-Line* with my " student ", 
in order for them to be able to see it clearly.

I realize Higher power would make it more visible,
but when the* Laser-Policemen* descend upon me,
I can proudly proclaim that I am 100 % LEGAL !


_


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## bradsystem

5mw isnt enough for sure..
someone said they are a more powerful even when they are marked 5mw,
i dont think.. just human eye is more sensible to green color, so when you compare green 5mw with red 5mw then you think green is more powerful.
i can make picture with 1w blue and 700mw green, green will be more visible even it have less power.
othervise recommend to ttvolcano if he live outside US to take 100-150mw


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## DoorKnob

I used to work at a laser company and agree with other poster, 5mw is fine for what you want to do. Since there's a price disparity, then you might just want to start with a cheapy and see if it meets your needs before spending on a higher power pointer.

In terms of lasers being dangerous it's already been said by others, primary danger is for you eyes, so just don't point it anyone's eyes. Don't point it at aircraft. Also, I've heard that it's illegal to use one if you're in the flight path of an airport even if you're just pointing at stars.


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## Illum

Amateur astronomer here. 5mw will work if you live in the midwest and not close to any light domes, in most places with street lights, 5mw is sufficient for personal use such as alignment or general purpose navigation. If you need to point something out for a friend, visitor, or anyone else that can't read a star chart, I find a 15-30mw to be perfect and anything around 5mw too dim. Anything above and you'll have a hard time distinguishing what is the end of sight on the laser and what is the deep sky object that you're trying to point to. I've use a optotronics [73mw certified] 532nm laser before and for all formal purposes overkill. I'm currently using a Laserglow Lyra [5mw] and a optotronics [32mw certified] and they have been more than sufficient for me in the last 4 years or so.


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## Quest4fire

> i can make picture with 1w blue and 700mw green, green will be more visible even it have less power.



The wavelength of the green laser is closer to the center of the visible light spectrum. It will appear more intense than the blue under normal circumstances.


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## Bigpal

Tt,
I got this green laser from Supersaving360 on Ebay. It's $15 and it is absolutely able to stargaze. It is bright. You clearly see the green beam at night and slightly at daytime. I have yet to find something it can't reach. It will hit stuff on the horizon if you have a good vantage point.

I was going to link the auction, but not sure if that's ok. But here is the auction title:

*Military Green Laser Pointer Pen High Power Super Bright 5mw 5 Mile Range
*
And it looks like this:










from supersaving360


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## Espionage Studio

The green is quite visable at low power, I love it.


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## laserlooser

blasterman said:


> They aren't dangerous. A 5mw green just has more potential for an idiot to be more of an idiot with one.
> 
> Something in the 30-40mw range should be fine for star pointing. While 5mw can work for this, if it's a dry night the brighter pointer is more visible off axis.



wrong thats a good way of getting someone locked up and theres no real way of knowing how far the laser will reach in the nights sky but you can be shaw i t wll attract the attention of local law enforcement (idiots on patrol) and cost you time money and a possible jail sentence


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## Illum

laserlooser said:


> wrong thats a good way of getting someone locked up and theres no real way of knowing how far the laser will reach in the nights sky but you can be shaw i t wll attract the attention of local law enforcement (idiots on patrol) and cost you time money and a possible jail sentence



Yes, this is true... star pointing has one rule to remember, if it has a pair of navigation lights and/or a strobe on the underbelly, don't point in that general area. Pointing a laser on an airplane will get you a felony, but responsible uses of reasonable powered lasers have been legal for many years. Stars will appear to twinkle from atmospheric convection, but I have yet to be confronted by someone who couldn't tell a pair of navigational strobes with a blinking star.

http://laserpointersafety.com/laser-hazards_aircraft/laser-hazards_aircraft.html

Let your conscience be your guide, and for those with class IV lasers...the warning should be quite obvious



Artist illustration


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## jklasers

*star-pointing*

There is nothing wrong or inappropriate about using a laser pointer of less than 5mW for pointing out the stars. Green laser pointers are generally banned at large star parties because they interfere with those imaging, and many of them in the air at the same time is a big distraction to those who seek out a dark sky environment. 5mW of green light is plenty of power for that application.


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## Vinco

Hello, a 5mw laser is enough to see the beam itself at night, 5mw+ is brighter and better, but you need googles, because it could make you blind.


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## linkcom

ttvolcano said:


> I am an astrophile and want a green laser for star-pointing. in photonlexicon forum, guys remind me that laser pointers with high power is dangerous and advise me to ask for opinoins in this forum. i find one with less power and much lower price 5mW 532nm Green Laser Pointer Pen compared with the previous one. but the point is if one with low power can be used for star-pointing. Is it bright enough or can it shot that far?



yes, 5mW 532nm Green Laser Pointer it is bright enouth and it is far, Phase for high-power laser pointer, it is safe, it can be used as a baton 
 juelie eforbatt


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## wearechampion

I have owned several laser pointers and this one is built to last. I mainly got this for messing with my cats, but I was surprised how powerful it is. I love the fact that you can use regular batteries rather than the button batteries. This is probably the best laser pointer you can buy before getting the really expensive, see the beam in daylight type models.


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## Eidetic

*Re: star-pointing*



jklasers said:


> There is nothing wrong or inappropriate about using a laser pointer of less than 5mW for pointing out the stars. Green laser pointers are generally banned at large star parties because they interfere with those imaging, and many of them in the air at the same time is a big distraction to those who seek out a dark sky environment. 5mW of green light is plenty of power for that application.



I agree with jklasers 100%. Go up to 10mW maybe, but anything more is unnecessary for star pointing. People using more power than that is why green lasers specifically are generally banned from large starparties and frowned upon at smaller gatherings. It's not just the astrophotographers that don't like them there. It's the undisciplined waving around of them in the dark by those more interested in playing with lasers than observing that makes them unwelcome. Also, NEVER mount a laser to a telescope for pointing. Scope gets bumped, laser beam gets pointed toward who knows what, and it stationary at face level or lower. Very bad news. Leave the lasers off the telescopes!


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## Arilou

wearechampion said:


> I have owned several laser pointers and this one is built to last. I mainly got this for messing with my cats, but I was surprised how powerful it is. I love the fact that you can use regular batteries rather than the button batteries. This is probably the best laser pointer you can buy before getting the really expensive, see the beam in daylight type models.



It's really hit-and-miss with those cheap chinese lasers, as the quality control is poor. Some are brighter than others, and I've had them break (usually the button). I've found that 1.5V alkaline batteries sometimes work a bit better than 1.2V NiMH, but it depends on the manufacturer. I bought some from phytechshop on ebay recently that turned out to be okay. The beam of the green laser is visible. Claims to be 5mW, but chinese suppliers can be a bit inconsistent about that. It's a bit brighter than I'd want to use as a cat toy.


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## wearechampion

Arilou said:


> It's really hit-and-miss with those cheap chinese lasers, as the quality control is poor. Some are brighter than others, and I've had them break (usually the button). I've found that 1.5V alkaline batteries sometimes work a bit better than 1.2V NiMH, but it depends on the manufacturer. I bought some from phytechshop on ebay recently that turned out to be okay. The beam of the green laser is visible. Claims to be 5mW, but chinese suppliers can be a bit inconsistent about that. It's a bit brighter than I'd want to use as a cat toy.


Yeah, as you say, I have bought a 1000mW 532nm High-power Green Laser Pointer, Very Bright! Exactly what i was looking for. Very sturdy, nice case. Works perfectly and really so cheap. I guess it is from the chinese lasers manufacturer, the online shop is _link removed...Bill_, it is first time to buy laser pen here, maybe i am lucky enough.LOL.


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## Arilou

Are you shilling for this vendor? 1000mW is absolutely insane to be using for star-pointing.


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## FRITZHID

In personal experience, a 5mw is on the dim side for star pointing, 75-100mw is a tad overkill. the 35mw I got from fleabay did quite well. Nice thin bright beam others could see it very easily. Both my 75 and 100 mw lasers have a slightly larger beam that just doesn't do it for me when star gazing, not to mention far more hazardous and draws too much attn.


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## Arilou

FRITZHID said:


> In personal experience, a 5mw is on the dim side for star pointing, 75-100mw is a tad overkill. the 35mw I got from fleabay did quite well. Nice thin bright beam others could see it very easily. Both my 75 and 100 mw lasers have a slightly larger beam that just doesn't do it for me when star gazing, not to mention far more hazardous and draws too much attn.



The lasers I bought from ebay claimed to be 5mW, but look brighter than that. A review of another laser from the same seller claimed it was ~35mW. https://www.youtube.com/watch?v=s0jOHyD8igo

I would recommend the 532nm green laser over the 405nm one, as it is hard to see the near-uv beam.


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## FRITZHID

Arilou said:


> The lasers I bought from ebay claimed to be 5mW, but look brighter than that. A review of another laser from the same seller claimed it was ~35mW. https://www.youtube.com/watch?v=s0jOHyD8igo
> 
> I would recommend the 532nm green laser over the 405nm one, as it is hard to see the near-uv beam.




Yes, green much better than blue, and if you can afford it, yellow.


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## Capolini

I have a green laser 532mn 5mW. I don't use it too much anymore, but I am amazed by it. For me it is sufficient enough to point at stars, constellations, ect.

I am not positive but I believe the beam can go around 2 or 3 miles! I need to be in the Mts. and shine it down towards a valley to get a better idea!


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## markr6

Capolini said:


> I have a green laser 532mn 5mW. I don't use it too much anymore, but I am amazed by it. For me it is sufficient enough to point at stars, constellations, ect.
> 
> I am not positive but I believe the beam can go around 2 or 3 miles! I need to be in the Mts. and shine it down towards a valley to get a better idea!



They are pretty amazing. I bought a cheap one on Amazon for $2.97 shipped!! I liked it so much I bought a second one, exact same model and seller, but it hardly works. At that price, it's worth a gamble.

It said it was <=5mW, but there's no way! Has to be much more but I don't have anything to measure it with.

I just purchased my first 18650 laser...it also said 5mW, but I think the QC is so bad you can end up with anything from 5mW to 100mW!


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