35mW Laser seems weak

dannician · Jul 16, 2015

I purchased a 35mW laser and it seems weak to me. I was expecting to be able to star gaze and have others see the beam? If you are sighted right in the beam is visable to the one operating the laser but get just a few feet away to the side and it disappears. I live in a rural area so not much artificial light at night.

I bought form Optotronics. The laser was supposed to be at least 30mW and came tested at 36mW. I am working with them on returning or exchaning.

But I want to know...

Is 35mW too small for star gazing with a group of 10-15?

trussmonkey25 · Jul 16, 2015

dannician said:
I purchased a 35mW laser and it seems weak to me. I was expecting to be able to star gaze and have others see the beam? If you are sighted right in the beam is visable to the one operating the laser but get just a few feet away to the side and it disappears. I live in a rural area so not much artificial light at night.

I bought form Optotronics. The laser was supposed to be at least 30mW and came tested at 36mW. I am working with them on returning or exchaning.

But I want to know...

Is 35mW too small for star gazing with a group of 10-15?

You need something about 150mw or more for this in my experience. Exchange it for a more powerful one

mortuus · Jul 16, 2015

That should be enough i have a 40mW pen and i have no issues see the beam at night if i point it at the sky.. are u using fresh batteries or ?

dannician · Jul 16, 2015

At first no but I put in fresh Duracel brand and it did get a little brighter.

Seems like the 30mW would be brighter based on what I have read and the videos I watched in my research.

Again... just a few feet away to the side and it is gone.

icecruncher · Jul 16, 2015

dannician said:
At first no but I put in fresh Duracel brand and it did get a little brighter.

Seems like the 30mW would be brighter based on what I have read and the videos I watched in my research.

Again... just a few feet away to the side and it is gone.

Normal

It depends on particulate matter in the air. Fog or smoke will make it really visible, but on a clear night it isn't going to be spectacular.

I have picked up "cheap" green pointers that put out over 50mw and they are only decent outside.

dannician · Jul 16, 2015

Hmmm... I know it is subjective but I wonder what people mean when they say the laser is really bright in their reviews. I would call this laser mostly dim

APEX1 · Jul 17, 2015

add some fog and it'll be just fine. a lot of people do it. I do it with all my lasers

Benm · Jul 17, 2015

The visibility of the beam more or less depends on particulate matter in the air. If you use the laser outdoors in an area with very little dust pollution (might be the case in rural areas) there will not be much to see.

Light does scatter from clean air too, but this effect is really minimal - otherwise you wouldn't be able to see the sun on a clear day or the stars at night.

I obviously have no idea of the actual power output of your laser pointer, and without a meter neither do you. If its actually 30-36 mW you should be able to get some smoke from black plastic if you focus the beam as narrowly as possible. If it has no focus adjustment this will require an external lens.

Pman · Jul 17, 2015

Like others have said the particles in the air make a tremendous difference and if you had a very clear night and the air was still it wouldn't look impressive especially if part of the output is IR.
I have a 32mW right here in my bedroom and the beam is easily seen but that would be expected. When someone comments on the beam for the first time it is usually from turning it on inside and then later taking it out at night. You would be very surprised how bright that 532nm would be at 100mW or more for sure.
You could try a couple of lithium advanced cells or even a single 10440 cell with a dummy/spacer that fully charged will be at 4.2V if you want to take a chance as every higher quality pen laser I have purchased has put out far more output with more voltage in.

mikeylee25 · Jul 17, 2015

so the higher the nm the more distance or visibility it is?

NightExplorer96 · Jul 17, 2015

mikeylee25 said:
so the higher the nm the more distance or visibility it is?

Nope. nm just defines the wavelength, or color your laser will produce.

Our eyes have a peak daylight sensitivity of 555nm, so any laser as close to that number as possible will prove to be the brightest per mW. At nighttime, this drops to around 507nm, meaning the same as above

-Alex

GSS · Jul 17, 2015

I have some high output lithioms in my cheep green 532nm and they made a big difference and no problems so far but a while back on a thread Jack from optrotronics warned not to exceed 1.6 per battery on his, this was an old thread mabey its changed but get in touch with him he will gladly help you.

dannician · Jul 17, 2015

I am wanting to get a laser powerful enough to do astronomy presentations with groups of 15-20. We could say the group will make a 20' radius. I need them to see something of the beam as they are beginners. What mW is recommended?

doubleone44 · Jul 17, 2015

I would say 100-150mW. Depends on where you live. In rural areas there ate usually less particles so the beams will be less visible

GSS · Jul 17, 2015

dannician said:
I am wanting to get a laser powerful enough to do astronomy presentations with groups of 15-20. We could say the group will make a 20' radius. I need them to see something of the beam as they are beginners. What mW is recommended?

If your working with Jack from optrotronics and he will let you exchange at this point, talk to him he will point you in the right way he was great with me, if you think the beam needs just a little bump go with his next level, or so on. It seems you will be useing it for teaching quite often so I would recomend to stay with him at this point, he makes a first class product in mine and just about everyone else opinion. If no city pollution is an issue and it will be only used outside, go at least with his 75mw

Benm · Jul 18, 2015

A small increase in power would probably not cut it though if your current laser is totally in adequate given your circumstances. The brightness gain from moving from say 35 to 50 mW really is neglible. You could easily tell the difference with both units side by side, but otherwise it would be marginal.

Pointers to use for astronomy in unpolluted areas may have to be very powreful to be of any use. The same thing that makes these locations good for stargazing makes them bad for seeing laser beams.

Obviously using high power lasers here is very dangerous since the spectators will probably have fully dilated pupils and a random hit across the eye by something like a 200 mW pointer would be damaging. For this reason i'd suggest using something that has a momentary pushputton you need to hold so it turns off if you drop it for any reason, and take extreme precaution to keep the beam from your audience.

35mW Laser seems weak

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