are 1mW green laser pointers worth bothering with?

[mark3d]

will a decent 1mW green laser pointer allow you to point out stars to 3-4 people around you?

the usefulness of it would make it worth spending the money to get a good one.. but not if its a waste of money! :) if it's worth it then some suggestions would be great :)


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[marki]

Hi Mark

You will need at least a 5 mw to make it practical.

Cheers

Mark

[mark3d]

thanks Mark. I dont think we can apply for a permit in SA for over 1mW, so it look like its not going to happen.

We will have to stick with "that star to the left and down a bit from those two close together.." :doh:

[marki]

We are not supposed to have them over 1mw here as well but it is not really enforced and the police are only concerned if you point it at a person or aircraft in flight. Not sure what the SA rules are but try one of your astro shops to find out. If you can argue your point that the laser will be used strickley for educational purposes only you may be able to get one.

Mark

[Rigel003]

There are supposed to be discussions in the pipeline that will result in ASSA members getting a general exemption when the law comes in.

[mark3d]

that would be a sensibe outcome. here's hoping it works out! thanks

[erick]

I'd like to hear a test of this one sold by Telescopes & Astronomy. Not cheap, but no permit would be required in Victoria.

http://www.telescopes-astronomy.com.au/green-laser-pointers-international-supplier.htm

[Barrykgerdes]

My 5mw laser pointer is adequate for a dark location but is border line where there is any light polution. Most of the others I see are much brighter than mine. I can't recall seeing a 1 mw in operation. However mine is a few years old now and the efficiency of the 1 mw may have been improved.

Barry

[Liz]

I have just bought a 1 mw, to help out with 100 Hours of Astronomy nights, but its useless :sadeyes: Will return it Monday, and get a 5 mw from somewhere else.
I still have a cheapie laser from Ebay, sitting at Brisbane Customs that they confiscated, but I cant be bothered with the paperwork required to get it.

[marki]

I went through the import process just to see what it was like when they first passed the law. Bit of a pain as it takes about 6 weeks. Interestingly after waiting that time I was informed that laser collimators were not on the controlled list and mine is 5mw and is very much like a hand held laser. Hmmmmmmmmm, does that give anyone ideas :). Only thing is its red but I imagine it would be possible to get one in green.

Mark

[mark3d]

i understand there is a huge discrepancy in ratings of cheap lasers. so what may be labelled 5mW might only be 1mW, so i was hoping it's possible a good 1mW may be OK, as it would be safe to take anywhere.

i would prefer to see SA asto society members get an exemption.

[Jay-qu]

This is odd.. I have a 1mW rated green laser and it works extremely well for pointing out stars for 2-3 people around me. With dark adapted eyes you can see the laser beam at almost right angles.

I once tested the power output with a light meter and it is definitely below 1mW (about .7mW without new batteries).

I dont know of how much this one cost as I got it as a present.. but you do have to be careful with cheap ones. They can have poor focus and may just be lying about their output. It would be best if you could test it with a light meter.

[erick]

I had wondered about that. The better laser collimators typically have 5mW lasers in them. Red, usually.

[Jay-qu]

Ok so I went and retested my friends "1mW" laser.. with fairly new batteries it may or may not have had a peak output of ~4mW, more stable operation at 2.2mW :whistle:

That may explain why it is pretty good at pointing things out..

[marki]

In my experience the 1mw are great for pointing out features of interest on power point presentations as the dot can be well seen on a screen. The beam itself is not obvious so they would not be good for astronomy unless used in a dust storm which would make the stars very difficult to see :D.

Mark

[rider]

you can legally buy them in Queensland, come for a holiday!

http://118.127.11.230/catalog/product_info.php?cPath=37&products_id=162

http://www.sirius-optics.com.au/laser%20pointer.htm

of course you will only use it while your here, wont you?

[Starkler]

20mw is too much! Id be happy with a bona-fide 5mw :sadeyes:

[mark3d]

i considered buying one here before they banned them, but i just don't like the idea of being in possession of what is legally equivalent to a machine gun and could get you 14 years! i'm sure its highly unlikely to be caught in the first place, and even then the police may selectively enforce the law if it's obvious you are using it for astronomy. that's a lot of ifs...

the only reasonable solution for me is a good quality 1mW, or an exemption for astro society members.


.

[marki]

I understand your position Mark. Here they are only compared to a machine gun if you actually point them at someone otherwise the police couldn't care less. The people governing the radiology stuff are actually supposed to regulate lasers here but don't seem to be very effective in doing so. Still I would object strongly to any interference as I use mine responsibly for both work and play. I stilll think you should check out laser collimaters as they are not illegal any where that I know of.

Mark

[Terry B]

I compared my allegedly 5mw one to a friends alleged 30mw pointer on the weekend at our 100hrs event.
Admittedly mine lives in my pocket to keep it warm and his was mounted on a finder but I couldn't notice any difference. Both worked well enough and sadly both illuminated the clouds that were over us at the time.:cloudy:
I find that temperature is the biggest killer with mine and it needs to be warm to give a nice beam.

[MrB]

A stroll into any Jaycar electronics store will net you a 10mW green laser module.
They're behind the counter, ask for a ST3117. ;)

[Starkler]

Hehe cool. It could fit inside the telrad, shining through a hole and run off the same batteries :lol:

[charlieaus]

Hi, Jay-Qu,
Could you tell me what Light Meter you used to rest your laser power output? I believe my laser power is a lot lower than claimed so I desperately look for a meter to find out the true output power. Thanks.

[Jay-qu]

I cant remember the exact model sorry, it was just one hanging around an optics lab at my university. I imagine even one used for photography could give you a good reading - just take note of the ambient reading before you point the laser at it.

[charlieaus]

Jay-Qu,
Thanks for the reply.
But how did you work out power output in mW?
Cheers.

[Jay-qu]

Oh, well I shone my laser of the photodiode of the detector and the screen tells me the incident power in mW - nice and easy :)

[charlieaus]

So, it must be a laser power / energy meter.

[Jay-qu]

Im pretty sure its a fairly average light meter. Light intensity can be measured in many ways, candels, lumens. But this light meter had the option to display the total energy per second (Watts) that was hitting the sensor. Other light intensity units may be some variant of energy per second per unit area. In which case the device would just divide by the area of photodiode detector.