Deciding between 1.1W 450 or 100+mW 532

[WarFreak131]

Hello all,
It's been quite a while since I've posted here. Anyway, I am trying to decide between a 1.1W 450nm from Fast Tech (it's advertised as being b/w 1W and 2W, but a YouTube video I found showed it reaching 1.1W), or a 100+ mW green laser.

I have no intention of using this to burn stuff or to point in random directions, I am using this solely for astronomy reasons with my telescope, like pointing at stars and different points in the sky, etc. And don't worry, every astronomer with half a brain knows to watch out for planes.

I checked the relative brightnesses using that calculator website that floats around the forums, and a 1.1W 450 is equivalent to a 115mW 532.

So while I think a 1.1W 450nm would look great at an observing location, I don't want to have to worry about its capability to burn things and/or cause personal harm. While a 100mW could cause some damage, I'd still much rather have the same brightness at 1/11th the power level. In either case, I'd want to have a pair of laser glasses in case.

Personally, I've tried both name brand and New Wish-style 5mW green lasers. Those things are pathetic, IMO. The second they hit anything below 50 degree F, their power output drops, anything below 40 and they stop working altogether.

Does anyone have a suggestion for a 100+mW green laser that is accurately spec'd and wont crap out in the cold?

 

[3Pig]

I use my greenie way more than my 1W blue, its more visible, has a way better beam and goes further.

Problem with 532 greens is that they may struggle to get any output when cold, mine does nothing when its 15 degrees Celsius or lower, you could just keep it in your pocket in cold weather, or leave it on till it heats up enough.

 

[WarFreak131]

I use my greenie way more than my 1W blue, its more visible, has a way better beam and goes further.

Problem with 532 greens is that they may struggle to get any output when cold, mine does nothing when its 15 degrees Celsius or lower, you could just keep it in your pocket in cold weather, or leave it on till it heats up enough.

Thanks for the response. I originally would try to keep it in my pocket or run it to let itself heat up, but for the weaker 5mW ones, I think the heat was sucked away by the cold weather faster than the diode could warm up, so I was screwed either way.

Can you recommend a 532 between 100 and 200 mW accurately spec'd?

 

[3Pig]

Thanks for the response. I originally would try to keep it in my pocket or run it to let itself heat up, but for the weaker 5mW ones, I think the heat was sucked away by the cold weather faster than the diode could warm up, so I was screwed either way.

Can you recommend a 532 between 100 and 200 mW accurately spec'd?

SciFi Lasers has both DPSS 532nm lasers and direct diode 520nm (these will work in cold temps)

Heres a link to the 520: SF501B 520nm Forest Green

And the 532 which is way cheaper: SF501B 532nm Green

 

[WarFreak131]

Sweet, thanks a bunch, I'll check these out soon.

 

[BurningLaserGuy]

Isn't that too bright for astronomy? I mean our eyes have to get used with the darkness and then you point with an 100mW@532nm on the sky? Correct me if I'm wrong.

 

[mortuus]

dont see why a green would be too strong if you point to the sky? not like it will reflect or anything in your eyes.. But maybe u should look into getting a 520 instead since its diode u can even use it when its cold and 532 is very temp sensitive where a 520 is much more stable.

 

[clansley]

Isn't that too bright for astronomy? I mean our eyes have to get used with the darkness and then you point with an 100mW@532nm on the sky? Correct me if I'm wrong.

Even 50mW/520nm is very bright. If all the OP needs is to see a bright line in the dark then 100mW is more than they need.

 

[WarFreak131]

Isn't that too bright for astronomy? I mean our eyes have to get used with the darkness and then you point with an 100mW@532nm on the sky? Correct me if I'm wrong.

mortuus is right, theres really no dot to see since youre pointing the beam away at infinity. also, the brightness of the beam is negligible compared to the sources that really screw with your nightvision, like a guy who shows up to a star party with his headlights on.

 

[BurningLaserGuy]

mortuus is right, theres really no dot to see since youre pointing the beam away at infinity. also, the brightness of the beam is negligible compared to the sources that really screw with your nightvision, like a guy who shows up to a star party with his headlights on.

Dude! Compare the brightness of the star you are pointing with the one of a beam of an 100mW 532nm laser! Trust me! I was in astronomy a few years ago.... Do you ever had such a powerful laser?

 

[ultimatekaiser]

Dude! Compare the brightness of the star you are pointing with the one of a beam of an 100mW 532nm laser! Trust me! I was in astronomy a few years ago.... Do you ever had such a powerful laser?

I ususally use my galileo 5mW for a guide on my telescope and it works great. its very visible if you are in a sufficiently dark area. sometimes if that's not available i can coax it up to about 10 and it is plenty bright. anything much past that and the telescope is picking up the shadowing from the laser beam. i'll also point out that anything over 5mW it 'technically' not allowed to be used in a public setting (which includes the sky) so be mindful of where you point it.

I do agree that a 520 at somewhere closer to 20mW or so would probably be a better choice, as it will retain battery life at lower powers, and it will be less sensitive to cold or hot environments, where a DPSS pointer would struggle on a cold winter night. Though plain diodes dislike the cold too, but far less so, and they are faster to recover in your pocket.

I've even used (at home) my 543 HeNe which makes a rather spectacular beam at night at 4mW, which keeps itself warm from the discharge. It all just depends on what you're going for. even 40 mW of green is going to be blaringly bright against a dark sky with a 1mm or so beam

 

[BurningLaserGuy]

A lot of lpf members are astronomers too... lol

 

[WarFreak131]

It's weird how you say it's very bright, because my friend had a 75mW 532, and while it was bright, it wasn't like "wow that's goddamn bright!"

 

[USAbro]

Even 50mW/520nm is very bright. If all the OP needs is to see a bright line in the dark then 100mW is more than they need.

Correct. For beam purposes 100w is probably okay.

 

[clansley]

It's weird how you say it's very bright, because my friend had a 75mW 532, and while it was bright, it wasn't like "wow that's goddamn bright!"

Was it LPM'ed at 75mW or was that what the seller said? If it wasn't LPM'ed then it might have just be 25mW...

laserpointersafety has some outside tips, they suggest that for star pointing "The absolute limit for this application should be about 50 mW."

 

[BurningLaserGuy]

It's weird how you say it's very bright, because my friend had a 75mW 532, and while it was bright, it wasn't like "wow that's goddamn bright!"

I own a 20mW 532nm, I didn't used it on astronomy but my 15mW one. And I can tell you: it's perfect, maybe a bit to powerful, even a Chinese one will work. I don't know why you want to spend that much money for a laser that you won't use on taking beamshots or stuff... just using it on pointing stars... THIS is weird.