My 5mW laser (yes, I have a license from the Victorian Commissioner of Police!) does all I need. Yes, it is a bit dim in city skyglow, but it can be seen. I get the sense that the rating of a laser may not give the best indication of light output, especially amongst the cheapies on eBay. Some have not been happy with the 5mW lasers they obtained and have gone for higher wattage. Remember, as it gets colder, you need to keep green lasers warm. If the light dims in the cold, it may not be the batteries, but the laser itself. Keep it in your pocket to keep it functional.
The following could be of interest:-
http://www.telescopes-astronomy.com.au/astronomy129.htm
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NEW "LEGAL" 1MW GREEN LASER POINTER Most states in Australia have updated, adapted or legislated new laws for owning a Green Laser Pointer. The laws basically state, a 1mW (milli-watts) or less power output is legal. Greater than 1mW, in most states, requires permission from the Commissioner of Police - call your local Police Firearms Dept. You may need to have a good reason to own a laser greater than 1mW. South Australia (my state) still has no procedures in applying for permission for the more powerful than 1mW Lasers. There is a new system for classifying the lasers and their outputs. Most people are aware of the older system as showing the Class II Laser (<1mW) & Class III (>5mW) Lasers.
The most popular size for use in astronomy has been the 5mW Class IIIa Laser Pointers. It works well even in the suburbs and is powerful enough to show a larger crowd, in a darker location. Exceptions to this is when the Moon is out, washing out the night sky. Observatories and the like organistions, still hold sky tours when the Moon is out. In this case, a more powerful laser is needed and the 20mW is most suitable.
We are currently trialing a 1mW Laser (legal throughout Australia) to be available for astronomy. Ensuring the quality, and modifying the make up of the laser, has improved the brightness of the beam. This Laser will be best serving astronomers who use them as FinderScopes, as well as pointing out objects to someone next to you.
Benefits of the new 1mW Laser include:
- cheaper price (less than a 5mW)
- longer battery life
- more durable
- legal
Let us know if you are interested and we'll keep you posted.
Beware of crap lasers!"