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A laser for astronomy application as well as teaching use?

C

carnation

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i just know the green laser pointers are the prefered ones in astronomy use like star-pointing, but how much output power does it need to suit the needs best?
i'd like to watch the stars with my children often and then want one for pointing use when necessary.
i have one with 100mw output power but it is somewhat dazzling to me. so i want to buy one with less power.
is this exquisite green laser pointer suitable for astronomy application as well as teaching use?
 
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A laser for astronomy application as well as teaching use?
i just know the green laser pointers are the prefered ones in astronomy use like star-pointing, but how much output power does it need to suit the needs best?
i'd like to watch the stars with my children often and then want one for pointing use when necessary.
i have one with 100mw output power but it is somewhat dazzling to me. so i want to buy one with less power.
is this exquisite green laser pointer suitable for astronomy application as well as teaching use?
Click to expand...
1. Welcome to LPF :)
2. You are better off buying a green laser pointer off eBay. They are cheap and even though it says 5mW, they most Of the time end up being 10-20mW.
 
For teaching, e.g. presentations, you should use a red laser pointer, as they are much easier on the eyes than green laser pointers.

For astronomy, you don't need more than a 5mW green laser, and it shouldn't be much more powerful than that because it'll be 1) dangerous to students, 2) you'll ruin your night-time vision with too much light, especially for astronomy. The sad thing is that it'll be harder to get one that is 5mW than one that is more powerful than 5mW because they're generally over spec.

So what should you buy? Maybe get one of those 2-in-1 red/green laser pointers like this.
 
If you want to be able to point with the beam, 30mW should be more than enough at night. I would actually go for a 15mW pointer if possible because most put out more than they say they do at low powers. A cheap red for inside use would be good for your other teaching.
 
Bionic-Badger said:
For teaching, e.g. presentations, you should use a red laser pointer, as they are much easier on the eyes than green laser pointers.

For astronomy, you don't need more than a 5mW green laser, and it shouldn't be much more powerful than that because it'll be 1) dangerous to students, 2) you'll ruin your night-time vision with too much light, especially for astronomy. The sad thing is that it'll be harder to get one that is 5mW than one that is more powerful than 5mW because they're generally over spec.

So what should you buy? Maybe get one of those 2-in-1 red/green laser pointers like this.
Click to expand...

Thanks Bionic-Badger. but i doubt a green one with only 5w or less output power can meet astronomy needs.
admittedly, i have limited knowledge about this. i just show my doubt.
 
At night, when your eyes are well-adjusted to the dark, the green laser should have a visible beam. You don't want a beam too bright at night if you're doing astronomy. Any brighter and you're basically just showing off the laser to your students instead of using a useful astronomy tool.

I just tested my 5mW green laser (just metered it at exactly 5mW) and the beam is visible in the dark in my house and my eyes are not well adjusted. I would expect that any 5mW green laser pointer you get will probably be above 5mW anyway, so it should be much more visible.

In any case, for teaching in class I would not use a green laser pointer. They're very hard to concentrate on because they're too bright to the point of annoyance. It's fine for presentations to large audiences, but not in a classroom.
 
Thanks Bionic-Badger. yeah, exactly, the green one is not suitable for teaching. i also admit that 5mW green laser is visible in the dark but i wonder whether it can reach far enough to point star. to be honest, i ve no idea about whether the output power affects the shooting range or distance.
 
If you'd like to buy a classroom red laser pointer, a very nice 635nm laser pointer can be purchased from AtlasNova. Atlasnova's 635nm laser pointer is eye-safe (5mW), but the 635nm wavelength is far brighter to the eye than the standard 660nm laser found in most laser pointers. I use one in my own laser pointer that I built using a 635nm 5mW laser diode.

For a green one, any 5mW green laser pointer you find will probably work for you. They'll probably be overspec as well, so a slightly more visible beam if you desire.
 
carnation said:
i just know the green laser pointers are the prefered ones in astronomy use like star-pointing, but how much output power does it need to suit the needs best?
i'd like to watch the stars with my children often and then want one for pointing use when necessary.
i have one with 100mw output power but it is somewhat dazzling to me. so i want to buy one with less power.
is this exquisite green laser pointer suitable for astronomy application as well as teaching use?
Click to expand...

I personally think the green one with a 20mw~50mw output power is suitable for astronomy. as to a red one for teasching, it might be a strech. green one is also OK.
 
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swans said:
I personally think the green one with a 20mw~50mw output power is suitable for astronomy. as to a red one for teasching, it might be a strech. green one is also OK.
Click to expand...
Thanks first. it sounds reasonable.
different people have different views. then how can i make a judement? is one with 20mw~50mw output power dangerous?
 
one with more than 5mw may be dangerous. you can get a goggles with you in case you burn your eyes or other parts of your body. i don't know if one with 5mw can meet astronomy needs as Bionic-Badger says. it will not cost too much. you can try it.
 
This will work great for your purposes I got it a month or so ago and they all work great, they are definitely more than 5mW my guess is 40mW 532nm 75mW 650nm and 100mW 405nm. For you the green one will work great for star pointing, the red will work great for teaching and the 405nm is just for some very minor burning power and of course the awesome glow effects it has. Over all the package is a great deal.
 
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