Post by Chicago Astronomer - Astro Joe on Mar 9, 2010 2:22:22 GMT -6
50 Milliwatts of Raw Green Laser Power
Over the years, my fellow astro buds have come to star parties and observation sessions with green lasers, pointing out this or that in our night skies, with a nice green beam shining toward the target.
- Red lasers are unusable and not normally visible.
The green laser pointers are quite cool, not only in guiding non-astro friends in what is up overhead while explaining and story telling, but to help direct telescopes to fainter objects when attached to the tube.
(Green being the easiest color to pick up by the eye regarding laser particle reflectivity.)
They all had 5 Milliwatt green lasers, and did a good job.
I always wanted one, but for one reason or another...I was always waiting for a "Good deal" somewhere...some place. And hoping to snag a little more powerful one.
Searching the internet, I found some that were not only more powerful...but very expensive - $100.00 +...and were not available in the U.S.. Disappointed, I was going to get a ordinary common 5mw green laser, as I really needed one for Chicago Astronomer star parties and Adler Planetarium public sessions.
I came across a site from China that had many lasers available in a host of variable powers. I saw this one for $27.00 - delivered - for a "50" Milliwatt green laser.
Naw...too good to be true.
But I took a chance and about a month later...it arrived. Well packaged, I eagerly slipped in the two double AA batteries, ( a major selling point for me as some use button or special size batteries), and in a well sunlit room, I could discern a healthy green beam.
Sweet!
I have used the laser on a few mini star parties since I received this and had very good results. In comparison to my buddies 5w green laser, this one is much brighter, thicker and goes out farther....but it is not as pinpoint sharp.
The guests to whom we explain the night skies, enjoy the laser greatly and impressed by the beam. The extra bright beam makes it easy to follow along in Chicago's light polluted skies.
Foggy Night Demonstration -
On the 8th of March 2010, Chicago got socked in with heavy fog - very heavy thick rolling fog...and a perfect time to demonstrate the laser.
I tested a ordinary 5 Mw red laser I use for presentations and the hefty 50 Mw green laser together for comparison.
Usually, the red laser beam is not at all visible in the night sky. Not a trace. But, with the heavy fog, there was some indication of a red beam....
Not bright at all, but at least I saw the beam.
Next I used the 50 Mw laser....
No comparison.
The 50 Mw Green Laser penetrated the night sky like a Star Wars light sabre....and very beacon like.
At all angles, the green beam shown brightly and steadily...and the heavy fog just intensified the light beam.
Shooting down the alley, it goes about maybe 100 feet...?
(One evening, I will have an assistant help me measure how far the main beam goes while I measure it out horizontally.)
This is the brightest green laser I have seen anywhere and a great astronomical tool. The power consumption is good, as I have been using the same double AA batteries since I received it two months ago - (and cheap batteries at that.)
It appears the the cold has an effect on performance - as the momentary on/off button seems to make erratic contact and the beam illumination dims...until it heats up. I have kept it in my inner shirt pocket during bitter cold nights, using body heat to maintain the laser in some warmth, but it's a hassle to fumble around for it when needed...especially with gloves.
A fellow astro bud thinks that they overclocked this laser and 50 Mw is just a guess. I don't know, nor do I know the expected life span, but I'm going to enjoy using it - pointing out celestial objects for guests and thinking about mounting it on the Celestron 11 Inch SCT as a navigation aid.
"Do you expect me to talk?"
No Mr. Bond...I expect you to die!"
