1mw Laser Pointer Question.

[Renato1]

If I get 5 or 10 legal 1mW laser pointers, and then bunch them with rubber bands and turn them on, visually, would they have nearly as much Oomph as individual 5mW and 10mW laser pointers?

Or would I just have the effect of 5 or 10 dud 1 mW laser pointers?
Regards,
Renato

[RB]

Not practical doing it like that, ie: to get the dots to line up.
You need to combine the beams using a beam combiner.
In theory though the dot will look brighter.

This is just hypothetical though, right?

:P

[Renato1]

Thanks, but no - not theoretical. I was hoping to get nice multiple beams bright enough so that when I've aimed them at a bright DSO in the sky, people can follow them with their binoculars and go straight to the DSO.

And not have any reason for police to hassle me.
Cheers,
Renato

[RB]

What you'll end up with is multiple parallel beams though.
Granted they'll be close together but not close enough to be one coherent beam.

[Renato1]

Hopefully, near enough would be good enough, though they would peter out at a lower height than a 5mW or 10mW laser would.

I've ordered two as a result of another thread, I was just wondering if I should see if two are better than one - or take a punt and go and buy another three.
Cheers,
Renato

[RB]

Ok goodluck.

:)

[jenchris]

I point my scope by shining the laser down my ep hole the beam is amazing and I dont need a sighting scope.
I expect doing two at once may combine them.

[Renato1]

Are you sending messages into space?:D

When I get my two, I'll experiment with Blutack and see how it might be useful for aiming a telescope.
Cheers,
Renato

[sharpiel]

Remember Ghostbusters... Care when crossing the beams :D

[LewisM]

Bunching 10000000000000000000000000000000000 000 laser pointers individually is not going to intensify the beam - you have to COMBINE them into one coherant beam.

The best way is simply to get a higher wattage laser.

[jenchris]

Out of phase light from two sources will interact and diverge is what you're saying?

[big_dav_2001]

All you will get is a bunch of parallel beams, each only as bright as the individual wattage... If you can't see one beam from 2m away, you won't be able to see 5 parallel beams (or however many you use) from 2m away because they will not be any brighter than the individual because they are parallel...

If you focus all the beams into one, only then will you see any increase in overall brightness...

Davin

[RB]

... and there's no practicle way to focus/combine the beams unless you use a beam combiner.

:)

[Renato1]

I always enjoy that film - but darned if I can remember that reference at the moment.
Cheers,
Renato

[Renato1]

But that requires a $60 a year licence!
Cheers,
Renato

[Renato1]

Hi Davin,
If one beam sends X amount of photons to my eyes, or to the eyes of people tracing the beam with binoculars, wouldn't 5 beams send 5xX amount of photons towards our eyes?

If X=0, then I agree, it would be pointless, but I'd hope the value was higher than that.
Cheers,
Renato

[Renato1]

No, I was just wondering if five parallel beams from five 1mW lasers (where each beam can be seen as a ray going into the sky) would nearly as good as a 5mW laser, or not much good.

So that if the combined lasers were nearly as good at pointing out celestial objects as with a 5mW laser, when the Police come knocking I could show full compliance with the law.

Cheers,
Renato

[Renato1]

Anyhow - curiosity has gotten the best of me. I just ordered another three lasers.

I'll have a definitive answer next week as to whether it's a good idea or whether my niece and nephews get a laser pointer in their Christmas stockings.
Cheers,
Renato

[sharpiel]

http://m.youtube.com/watch?v=jyaLZHiJJnE

Beams...streams...same, same. Don't destroy the universe!

[ericwbenson]

Five lasers can make five parallel beams, getting them parallel and keeping them there you will find to be <extremely> difficult. But if you could do it to within an angle less then the beam divergence (about 1 mrad or so, which is ~3 arc minutes !!!) then at a distance the five beams will overlap and it will appear brighter. That distance depends on how close you can get the barrels and the beam divergence. Unfortunately that distance might be so far away that the five times intensity gain is swamped by the 1/r^2 intensity drop due to distance, so it may gain nothing.

The beams are not coherent (aka in phase) with each other but for the purposes of scattering off dust particles that doesn't matter.

BTW you can't use a beam combiner for lasers of the same wavelength, you can combine two linearly polarized lasers, but that's it.

Best,
EB

[Renato1]

Oh - that bit. Now I understand thanks,
Renato

[Renato1]

Thanks. Just thinking about it further, the barrels of the laser tubes would have to be parallel, and depending on the placement of buttons and pocket clip, one may only be able to get three and/or four tubes against each other. If three or four tubes against each other produced parallel beams, then one could put bunches of those numbers together.

That said, it all really depends on how bright a 1mW beam is. I have no idea. From memory, a 5 mW beam wasn't all that bright unless one was somewhere pretty dark.
Regards,
Renato

[Stardrifter_WA]

Hi Renato

Be aware Renato that some so called 5mW lasers are not actually 5mW, even if they are marked as being such, and that may be why you think they are not that bright. I have a 5mW GL Laser Rifle Sight (which cost $265), and that is definitely bright enough for astro use.

Cheers Pete

[Renato1]

Thanks Peter,
Your point also raises the interesting issue - as a laser rifle sight it is legal, but if you use it for something harmless to show people the planets and constellations...... then it is doing the same thing as a prohibited weapon!
Maybe you have to keep it on your rifle to keep it legal for astronomy usage?
Cheers,
Renato

[LewisM]

Laser sight is legal (in QLD) IF you have a valid/current firearms license - cost for initial license is around $300 - the laser cannot be purchased without the license - AND you add it onto your license (currently $38.34 in QLD per application or something) AND you have a legitimate requirement for it (which is submitted at the point of application for permit - they are VERY stringent in what is acceptable use - I said Astronomical use, which they approved).

So, no, it's NOT as simple as you think.

The 5mW green one I have (ex-pistol, on license), as Peter says, is more than adequate to illuminate atmospheric particles for you to point at something in the sky.

[Renato1]

Fascinating stuff Lewis. Where you live you can thus effectively get a laser as part of a shooting licence, but down here in Victoria we have to pay $160 for a two year licence to own a laser for astronomy use.

I suspect though, that where you live, someone had a lot of discretion about the rifle laser for astronomy use. Could it be possible that someone else making the same application may have it rejected for that usage?

I wonder if the same could be the case in Victoria - in which case shooters pay less for having a laser, than do recreational astronomers?
Cheers,
Renato

[Stardrifter_WA]

Hi Renato,

In WA a GL laser is considered a "controlled weapon" meaning that it isn't illegal to own and use, as long as it is used for a legitimate purpose. I am allowed to use a GL Laser Weapon Sight for astro purposes, and in fact it makes a great finder (as shown in the attached photo). I got the mounting block from Stellarvue and attached the weapon sight to that. The weapon sight is available locally from Arctic Fox in Malaga (Western Australia). I am picking up a new one from them this week. I have to replace the one I gave to my son for his telescope. They are not cheap at $264 but they are very good, as they are very simple to align using the X-Y adjusters.

Astronomy is one of the legitimate purposes, although I also have a rifle licence anyway, so I am good on either front. I did some lobbying in this regard when they first proposed those laws here, and common sense ruled in the end.

However, get caught with one in your possession can lead to significant fines, unless you can prove you had it for legitimate purposes. For this reason, my GL laser rifle sight is always kept with my telescope. I also have a letter from the Minister for Police stating that astronomy is a legitimate purpose. In addition to that, I also keep a copy of a weapons import certificate in my box as well, as I previously imported another GL laser, which I have mounted on my 16".

Please note though, various states have different laws. WA has the most sensible law in this regard.

Cheers Peter

[Stardrifter_WA]

Ah, its simple for us Lewis. :D Qld is too strict about everything, it seems. WA have sensible laws in this regard, it is classed as a "controlled weapon" and you can own and use one, without paying any fees, as long as you have a legitimate purpose. Astronomy is a legitimate purpose, as I have a letter from the Minister of Police stating just that.

[Renato1]

Thanks Peter,
Good to see that one State is sensible. And that's one very nice looking laser and superb sight you have there.

A friend did try using a 5mW laser on rabbits years ago, hoping it would be better than a spotlight. The rabbits were unperturbed and happily hopped away. And that laser is a probited weapon over here, akin to a fully automatic rifle.

Curiously, kids are constantly making prohibited weapons, when they make slingshots.

But oddly, when I recently bought my 15 year old nephew a deadly 35 to 60lb compound hunting bow for his forthcoming birthday - well, not a problem. My nephew kept asking "Are you sure I don't need a licence for this?"

Cheers,
Renato

[Stardrifter_WA]

Hi Renato,

I don't know what the laws are in relation to compound bows. It is more likely that they too come under controlled weapons legislation. I have a compound bow too and don't need a licence. However, I believe that a "cross bow" is now a prohibited weapon in WA. Understandable really, as "cross bows" are deadly and are not really a sport weapon. I am surprised that a compound bow doesn't yet require a licence though.

I haven't used my compound bow for a while, as I can no longer pull back the 70lb draw weight, due to a wrist injury. :sadeyes:

Cheers Pete

[Renato1]

Hi Pete,
Yes crossbows are banned in Victoria too - which I thought strange, as the ones typically sold here were a lot less powerful than compound bows. All the Ebay ads say that no licence is required for a compound.

Can't you turn the poundage down on your 70lb one? I've got a 57 to 70lb one which gives me a work out drawing 57lbs. I've also got another one which I use more often at 50lbs - since I don't wreck arrows as much with it.

Though I'm having more fun with a cheap recurve riser, long bow.

I bought them because I was getting frustrated with all the foxes around here walking around like they owned the place, and wanted to take pot shots at them. Strangely, I haven't seen one since I bought the bows.
Cheers,
Renato

[Stardrifter_WA]

Hi Renato,

Yes, it is strange that crossbows are illegal yet compounds are not, as in the right hands, a compound is more dangerous that a crossbow. However, from the perspective of a beginner, a crossbow is much too easier to use, whereas, the compound requires a much higher level of skill.

From that point of view, I doubt most people who would use a crossbow, for nefarious purposes, would bother developing the skills to use a compound. Maybe? I don't have the mind of a criminal, so I don't know what their motivations are anyway.

I have backed of the draw weight of my compound, but unfortunately, it is still too much to draw any more. I had two severely broken wrists, which makes it difficult to hold and draw nowadays. I have tried a lower draw weight compound as well, but due to some nerve damage I have a slight shake now, which makes it rather interesting trying to hit the target with any accuracy. I really should sell my compound bow, it is of no use any more. :sadeyes:

Foxes are wily b's, so I am not surprised they didn't hang around after you got your compound bow. :lol: I used to shoot them on the farm, but they were always hard to get.

Cheers Pete

[LewisM]

Renato, hypertune those lasers, and you can vaporise the foxes :P

I dislocated my shoulder a few years ago. I could not even cock an air rifle at one point it was that bad, let alone draw a compound bow. I know the feeling all too well.

[Stardrifter_WA]

And just how do you hypertune a laser Lewis:question:

[LewisM]

I wasn't being literal Pete :) It does bring us full-circle again :P

[RB]

:lol:

[Stardrifter_WA]

I know. :) The word hypertuned is such an overused word that actually has no real meaning. Well, not according to any of the dictionaries I own, it doesn't. And, to be clear, I do know you can tune a laser though, but not just any laser.

[LewisM]

Your response is ultra premium :)

[Stardrifter_WA]

[QUOTE=LewisM;1118541]Your response is ultra premium :)[/QUOTE

I love the use of your words Lewis, hmm 'ultra premium', now I wonder what that is supposed to mean, in this context:question: Or, maybe I am not use to such superfluous words. :sadeyes:

[LewisM]

Seeing we are talking death rays, I decided to get the licensed zapper out today to play devil's advocate with my fluorites and FPL53's.

ANYWAY, I found out that even the scattered reflection of one of these puppies off a matt painted wall backdrop is enough to darned well cause blurring of the eye for a while. :(

They are that bright.

I admit to making dew-dew-dew sound effects... because I am an imbecile. :face:

[Stardrifter_WA]

Now, how can one argue with that:question:

[LewisM]

Nah, I didn't really - more a public service announcement before Renato blinds his cat, dog, postman, wife and every cockroach within a 10km radius (not a bad thing that last one).

[Stardrifter_WA]

:question:

[LewisM]

Doubter :P

I DID accidentally cop a scatter reflection once. It was not pleasant! I also got "tagged" twice flying night training out of Jandakot. Told Perth ATC, and by the time we did the next bounce-thump-crash & go, the WA plod had arrived on scene.

[Renato1]

Hi Pete,
Your wrist problems are most unfortunate. I assume you've done all the recommended exercises, and have no problem understanding what I suspect would be your frustration, as I have had something similar. I stretched a tendon in my right foot three years ago from using my mower on a slope where I live, and despite there being no damage that an ultrasound can find, despite all the exercises and therapy, it has never healed - I can't run anymore.

I can understand when they banned the pistol sized crossbows that they used to sell. They were easily concealed in a bag and could be used in a hold-up (I think some were).

There are some new compound bows on Ebay that go from 20lbs up to 55lbs (or more), though one always has to get the specs, as I've noticed that often the lowest draw weight is associated with a lower draw length.

There is another possible reason for the disappearance of the foxes. We were worried that they would do our new rag-doll cat in, so we kept her indoors till around 10am or later, by when the foxes usually stopped walking around. But a couple of months ago, during a full moon, the cat wouldn't come in. It was late at night when I saw the most amazing sight - our white, gentle rag-doll was chasing a terrified fox around our backyard!

Now we let her out much earlier.
Cheers,
Renato

[Renato1]

Hi Lewis,
I'm too busy trying to tune those bows of mine.

I dislocated a shoulder when trying to learn how to snow ski. I've never gone back to the snow fields.
Cheers,
Renato

[Stardrifter_WA]

Hi Renato,

Unfortunately, my wrists problem won't ever be fully resolved. The left wrist was badly smashed and was just wired back together and the right wrist was fractured and plated. It took a number of operation, much physio and time, but I do have full use of my wrists though. The wrists weren't the only thing that was pinned or plated though. :sadeyes: I had a serious motorcycle accident from which it took almost 15 years to recover.

I do have full use of the wrists, apart from being able to do such things as archery, partially because of the now inherent weakness and because of the nerve damage, resulting in a slight shake. Unfortunately, due to this and other injuries received, archery isn't the only thing I had to give up, but hey, I'm alive! :D I do miss archery though.

It doesn't surprise me that your cat chased the fox, as they are very skittish animals. There are examples of that on youtube. Cats are fearless. :lol:

Cheers Pete