Green lasers and operating temperatures. Are the specs accurate?

[WeeBilly1325]

Hello everybody, I'm new and have been researching the forum trying to find information on green lasers. I'd like to buy a green laser that rates around 30-50mW. I'm leaning towards the 50mW side, since the area I live in has very low humidity and I figure the extra power might help the beam show up.

Anyway, another problem that I'm considering is the fact that it gets quite cold here in the winter. I know that green lasers are highly temperature sensitive, so I've been looking pretty closely at laser specifications. I found this laser:

50mW Sniper Series Green Laser Pointer

They claim it operates down to 0C. Could this possibly be true? (If so, it could be perfect for me.)

On a related note, is the above laser the same as this one which is being sold by Lazerer?

LZCB - CYBER 532nm 50mW Focusable Green Laser Pointer

They certainly do look similar! If they're the same, I'd rather buy the cheaper one.

If it matters to anybody, I plain to use this laser on a telescope, for spotting purposes. If anybody has any advice, I'd love to hear it! (The temperature thing is kind of important to me. I've seen the issue addressed in this forum, but these numbers are so much lower than everything I've seen... are they too good to be true?)

Thank you very much!

 

[Shakenawake]

not sure about the temperature thing

are you using the telescope in daylight for terrestrial targets or at night for stars? 50mW will be very bright especially if it is extremely dark. it may interfere with the light you are trying to see from the stars. I might go with a red laser for this purpose, they are less bright, though you will need more power than a green would require to see the beam. I would get the lowest power possible that still allows for a visible beam in the area you will be viewing. also get the best divergence possible. you want a small number in front of the "mrad" rating, the smaller the better. If you do go with a green, I think 10 or 15mW should suffice. I would get a pen pointer from optotronics: Optotronics Product Details

look at that, one of the comments mentions it is perfect for telescope use. you're welcome

 

[WeeBilly1325]

Thanks Shakenawake,

No way would I ever aim a laser at anything on the ground. Certainly not if there could be people, in, on, or around! This laser would be mounted to a telescope and used for astronomical purposes only. I AM concerned about my night vision, so maybe 50mW is too powerful. (I've seen people post in this forum, and they're talking about getting 150mW lasers for astronomy.) I do have a dark sky, but the air is very dry... this is yet another reason I'm asking for people's advice!

For a while I was using a cheap eBay laser that I bought. It was rated at under 5mW. I could see the beam ok, but not great. The bigger problem was that laser was dying every time the temp dropped much at all. And then finally the whole laser just died. Dead, dead, dead. I only had it for a couple of months. (I only paid 5 dollars for it, so that isn't a problem... but I'd rather do some research than make the same mistake again.)

If possible, I'd like to pay less then 70 dollars for this laser. Way less, if that's doable!

I've seen people using red lasers and you couldn't even see the beam...

 

[Shakenawake]

I have a 300mW 660nm laser, and a 5mW 532nm laser with comparable divergence. my 300mW red has a beam that is just barely brighter than my 5mW green, that should give you an idea of the kind of power needed for a red, though 660nm is slightly less visible than 650nm, and much less visible than 638nm. I dont know if single mode 638s are made, but multi-mode 638s have horrible divergence, possibly the worst, not good for astronomy. you could email jack and ask about the temperature handling on those optotonics pointers if no one answers that portion of your question. I feel pretty comfortable saying those are the highest quality green pen pointers available, I believe the one I gave you a link to runs around $40

 

[WeeBilly1325]

Thanks!

It looks like I'm going to go with either the 30, or 40mW, Optotronics LP. Still trying to make up my mind.

I've traded a few emails with Jack, who seems honest and straight forward... which I appreciate greatly!

 

[Shakenawake]

I see these only have momentary switches, meaning you would need to find a way to hold down the button if it is not in your hand. I also thought these would have better duty cycles than optotronics lists. I just assumed 10mW was low powered enough to have an unlimited duty cycle. more to consider, I don't want to contribute to an unsatisfactory purchase. I stand by my claim that these are of the highest quality, and Jack is great, but maybe they aren't so perfect for your application

 

[WeeBilly1325]

I saw the duty cycle and I'm not concerned about it. I'll be using it on a dobsonian telescope, so I should be able to get things lined up pretty quickly. Assuming I know where I want to go before I start moving, and I'll only need to turn the laser on when I start getting close to my target.

For me, the biggest concern is the operating temperature required for a green laser. (I strongly suspect that Warn Laser's spec sheet is FOS, so moving to a higher qualty laser with "local" customer service was an easy decision. Optotronics gets good reviews in this forum, and Jack replies to emails quickly... which inspires confidence! Also, the fact that I found Warn listed in the list of companies to not deal with, in one of the forum's stickies... well, that was the final straw.) I might have to figure out some kind of system to keep the pointer warm in the winter. I doubt that I'll want to take the whole mounting bracket off the scope and put it in my pocket. (I know ScopeStuff sells something, but that would require some kind of power supply.) There's always foam insulation with "toe warmers," if it comes to that. We'll have to wait and see! I'm not going to worry about it. Now now, anyway. I'll figure something out.

I ordered a 30mW laser this morning. It's impossible for me to know if a 10mw would've been powerful enough, or that the 40mw would've been the way to go, or even the 55. I just went with the advice I got from you... and the middle ground. (Secretly, I'm hoping that Jack sends a laser that's a little closer to 40mW than 30... but I don't think it's going to make any difference to me. I'll be fine no matter what he sends. I could see my old <5mW laser, just not very well. What I should PROBABLY be hoping for, is a laser with a good "tight" laser beam. (I believe this is what people around here call "low divergence," but I could be wrong about that.))

Jack told me I should have my laser by Thursday or Friday. I can't wait! /tapping foot/

Thank you very much for your help! If the laser doesn't turn out to be perfect for my application, it's won't be your fault. I'm the one that decided to buy this laser. (You just gave me some well meant advice.)

Oh... I should say that I liked your idea of getting a more powerful red, or blue, laser. The thing is, I don't like the extra cost and I worry about carrying around all that extra power. From what I understand, these things aren't exactly "legal" to be carrying around. I don't plan on doing anything that'll get me into trouble but, still, I'd like to stick with as low a wattage as I possibly can. It's not a macho thing for me. It's just a aiming device/aid. (And, as I told Jack, the last thing I want to do is start a forest fire... or melt stars out of the sky!)

 

[WeeBilly1325]

Good grief! That got long! Sorry. (Sometimes I can be a wordy little bugger!)

 

[Shakenawake]

Glad to help. yes low divergence makes for tight beams. high powered blue lasers in the 445nm range have multi-mode diodes, thus bad divergence ratings. they would not be useful for your purposes. High powered lasers are technically supposed to have safety features, namely a safety key which must be inserted before the laser can power. It's unlikely a regular law enforcement person would know this. if you are responsible and safe, shouldn't be a problem. single-mode diodes have good divergence. single-mode diodes emit round dots, multi-mode diodes emit rectangular dots. I mentioned the reds because I heard they scatter less severely from the rayleigh effect, and I have seen photos of observatories using red lasers and yellow, though obviously at high powers. they are used to create a "star" for optics alignment or correcting, not sure about all the specifics. With your budget I think you made a wise choice, if you can find a way to hold down the button. I promise these opto pen pointers will have superb divergence, their high powered RPL series have the best divergence ratings I have ever seen without using a beam expander.

Not sure why warnlaser is advertised at the top of this site, I can't say I have heard anyone recommend them. I assume they pay the forum to advertise, personally I think quality is the best advertisement. I never heard a negative thing about optotronics.

finally, don't double post, which is posting again when no one else has. instead, use the edit button appearing at the bottom left of every post you make. no biggie, even I did it on my first thread and now you know.

As you see, I can be wordy too, doesn't bother me, reading doesn't strain my brain or attention span as much as it may others

Interestingly, scientists are now trying to start a fusion reaction using the worlds most powerful laser system. hydrogen fused to helium, just as in stars. doesn't get much hotter than that.