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FrozenGate by Avery

520nm v. 532nm

tuskiomi

tuskiomi

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Jan 28, 2015
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I want a nice beam laser for stargazing, but I want the beam to be clearly defined, and highly visible.
I was wondering what the comparisons of the two are as far as the following:
  • beam divergence
  • brightness in daylight
  • brightness at night (because sensitivity of wavelength changes at night)
  • IR emissions
  • Safety
  • Battery life
  • Power - sight ratio (vis1 * Pow1 = vis2 * Pow2 where vis1 = vis2)
  • price
If anything else should be added, please let me know!
:thanks:
 





532nm is the way to go. :)

DPSS lasers typically have much better divergence than diode lasers.

Peak visibility is ~555nm, so 532nm will be more visible, day or night.

532nm lasers DO have IR leakage (520nm doesn't), but most high quality lasers have filters installed, so as long as you get a good laser it shouldn't be of concern.

The disadvantages of DPSS over diode are mostly temperature-sensitivity and fragility. Depending on what kind of KTP you get your laser could either like it warm or cold, warm is typically better. And of course there are more components in DPSS lasers, so there's more to go wrong. They are also less power efficient than 520nm

IMO the advantages outweigh the disadvantages, and 532nm lasers are also typically cheaper.
 
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I agree with H2Oxide but to further evaluate seeing as you are from Minnesota I would take the temperatures into consideration as it get pretty darn cold there.
 
H2Oxide said:
532nm is the way to go. :)

DPSS lasers typically have much better divergence than diode lasers.

Peak visibility is ~555nm, so 532nm will be more visible, day or night.

532nm lasers DO have IR leakage (520nm doesn't), but most high quality lasers have filters installed, so as long as you get a good laser it shouldn't be of concern.

The disadvantages of DPSS over diode are mostly temperature-sensitivity and fragility. Depending on what kind of KTP you get your laser could either like it warm or cold, warm is typically better. And of course there are more components in DPSS lasers, so there's more to go wrong. They are also less power efficient than 520nm

IMO the advantages outweigh the disadvantages, and 532nm lasers are also typically cheaper.
Click to expand...

H20 gave you good advice, although 520nm lasers will be brighter at night due to out peak sensitivity dropping at around ~507nm during nighttime :)

Also. Yes, I am ThaGreenlander/LeHap/Islander haha :p I think I'll stick to this username. Tired of always picking new ones!

-Alex
 
Hap said:
H20 gave you good advice, although 520nm lasers will be brighter at night due to out peak sensitivity dropping at around ~507nm during nighttime :)

Also. Yes, I am ThaGreenlander/LeHap/Islander haha :p I think I'll stick to this username. Tired of always picking new ones!

-Alex
Click to expand...

Ahh yes, it does shift at night, I though it was closer to 530nm though, I guess not. :)

I see "Islander" didn't even last a whole week. :crackup:
 
Hap said:
H20 gave you good advice, although 520nm lasers will be brighter at night due to out peak sensitivity dropping at around ~507nm during nighttime :)

Also. Yes, I am ThaGreenlander/LeHap/Islander haha :p I think I'll stick to this username. Tired of always picking new ones!

-Alex
Click to expand...

Pick a damn name and stick to it! :D:D I can't keep up!
 
H2Oxide said:
532nm is the way to go. :)

DPSS lasers typically have much better divergence than diode lasers.

Peak visibility is ~555nm, so 532nm will be more visible, day or night.

532nm lasers DO have IR leakage (520nm doesn't), but most high quality lasers have filters installed, so as long as you get a good laser it shouldn't be of concern.

The disadvantages of DPSS over diode are mostly temperature-sensitivity and fragility. Depending on what kind of KTP you get your laser could either like it warm or cold, warm is typically better. And of course there are more components in DPSS lasers, so there's more to go wrong. They are also less power efficient than 520nm

IMO the advantages outweigh the disadvantages, and 532nm lasers are also typically cheaper.
Click to expand...

https://en.m.wikipedia.org/wiki/Spectral_sensitivity according to wikipedia, the sensitivity shifts to 507nm at night?
 
If you put an expander on a 520nm diode laser it will have low divergence too and no problems with temperature sensitivity.
 
You got some good advice here. I agree with 532nm being your best option and have a tip for you and the cold weather. I keep my dpss greens in my pants pocket when its really cold out. The human body keeps it at a good temp until you are ready to use it. Then activated laser will help keep the temp up by generating its own heat. That is how I used mine in really cold weather. Without warming the laser in my pants the spot wasn't even visible in sub freezing temperatures. Just keep something to protect the lens from debris and lint.

Hap said:
Hey! Im trying to keep you guys on your feet :beer:

-Alex
Click to expand...

You should stick to this name. Its really good that the admins here at LPF even allow name changes. Most forums do not. if you keep changing your name they may feel your taking advantage of this courtesy and no longer allow name changes. I am surprised they keep letting you do this. I had to change my name a month ago because of security breech on another website that my old username was the same at. I was very grateful they let me switch names rather than have to close the account and start from scratch loosing all my pictures, PM's, archives, ext.
 
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I read up on divergence. The divergence on 520s Is usually 10mRad, while 532s can do 2 mRad.
Ant suggestions on where to get a 500 mW 532 with a nice filter?
 
tuskiomi said:
I read up on divergence. The divergence on 520s Is usually 10mRad, while 532s can do 2 mRad.
Ant suggestions on where to get a 500 mW 532 with a nice filter?
Click to expand...

Whats your budget?
Does it have to be 500mW? (Seems pretty high for star pointing)
Does size of host matter?
Focus able or fixed focus? I'd recommend fixed unless you think you're going to try to burn stuff.
Preferred duty cycle?
Do you want any Safety features such as delay, shudder, key or pin?
Type of switch, rear clicky, side momentary?
 
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At the risk of over simplifying.

532 dpss = Laser beam.
520 MultiMode= Very focusable flashlight.

But there is hope for bigger single mode direct 520's
 
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My 1.4 watt 520nm flashlight, but it's divergence is far lower than any 532nm laser pointer using a normal 6mm diameter lens :p

big1.jpg
 
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