(Viewed 4,685 times)

[Chicago Astronomer - Astro Joe]

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!"

[Paulie pchris00]

I love it! As soon as I saw the first picture, I was thinking Star Wars, so I love the Yoda shot too. Don't let the Iranians or North Koreans get hold of one of those bad boys. They might want to start blowing planets out of the sky with it.

[RobbW]

Hi Joe, thanks for the comparison and the pics. I have a question about the use of lasers for pointing out celestial objects. I bought a 5mw (actually 4.999999mw) green laser from Jasper a couple months ago when it was deeply discounted. It is bright and powerful enough for my needs. My concern, however, is not about its power but rather it usage.

I have always been very hesitant to use my laser in the night sky for fear of inciting panic or having the cops called on me or the FAA sending its goons out to bust down my door. I'm always afraid it is going to draw too much attention or get me in trouble. Have you ever had any issues with actually using your laser during observing sessions? Especially if you use it during sessions at the Adler? With all the jets flying in from off the lake on their way to ORD, have you had any problems with accidentally lighting up a plane or anything else that maybe you shouldn't?

[Chicago Astronomer - Astro Joe]

Robb,

I am glad you appreciated the Green laser thread.

I use it all the time and it's like a light sabre with all that raw Chinese laser power.

But, no. I have had zero issues regarding it's usage and operation.

Chicago does have a lot of air traffic going about - so some smart usage is called for.


Some points to consider:

Look before you shoot -

If you take just a moment to scan the area of any aircraft, then you lessen any chance of "lighting up" any planes - which of course you must never do. Listen and look before pointing. In time, this becomes an automatic reflex.

Use quickly -

It should only be used for seconds at a time (3 seconds is average). It doesn't have to remain on constantly as you explain the reddish dot is Mars and the smudge is M45.

This will not only lengthen battery and laser life, but it also lessens any chance that a beam might accidentally hit an undesired object entering your field while explaining a point of interest.

Never lend -

Always keep the laser in possession.

The temptation of visitors and guests is to hit objects with the beam, including cars, people, aircraft and each others eyes. Not cool, and irresponsible. Keep it with on you and never leave it on a table or unattended

I do allow my trusted fellow astro buds handle the laser, (very few), as I know they use it smartly and carefully.

I intend to mount a green laser on my scope, to assist in aiming at celestial targets...and to make an impression for the guests. I think it's quite cool that the beam I send out, will continue to travel indefinitely, bounce off planets and the moon...and perhaps detected by sensitive alien instruments...

But Robb,

I don't think your occasional usage would raise any eyebrows if you are considerate and careful at each usage.

What part of the world do you look up at sky from?

[RobbW]

Those are some very good points you make, Joe. Well said! I am craning my neck to the heavens out here in Elgin; just a bit to the west of you.

My 4yo daughter has been expressing great interest in the stars, planets, and space in general lately. It has re-ignited a passion in astronomy that I had when I was younger. I just recently (couple days ago) bought a used scope off Craigs List, cleaned it up, and am now looking for time and places to use it. It is a Meade DS-2130AT. It's not a spectacular scope, but it was inexpensive and will help me and my daughter learn about the basics about the cosmos.

My wife and daughter are on vacation in Myrtle Beach, which has given me a couple nights alone to play with my scope. So, last night, I drove out west close to my hometown of Mt. Morris, IL in order to have darker skies. It was not a very good observing session as it was too windy to keep the scope steady. So I headed home around midnight, warmed up with a glass of red wine, and then went to bed.

Wife and daughter were supposed to be returning home tonight, but I just learned that their original flight has been cancelled. Looks like they are going to be rebooked on a flight tomorrow morning. So, I may look at taking the scope out again tonight. However, this time, I will probably look for someplace local so I don't have so far to drive home in case conditions are unfavorable.

[Chicago Astronomer - Astro Joe]

Robb,

It's very cool to have the astronomical spark re-ignited at any stage in ones life.

And your scope is a respectable one:

With Go-To and a 90mm aperture it's a good scope for exploring - the red wine is good too.

At sundown tonight (18 April 2010), , catch Venus & Mercury to the west, Mars up high and Saturn rising.

Keep us updated on your observations and experiences, as we enjoy sharing the enjoyment of observation. You are always welcome to join the the Chicago Astronomer crew on our sessions...perhaps when it gets warmer.

The good thing about the cosmos - is that they will always wait for you to come back.

[Paulie pchris00]

The picture above looks a lot like my scope, but mine is 114mm aperture. I'm not crazy about the "Go-To" Robb, but I've found that instead of going to through a huge hassle to get it perfectly aligned, if you're going to be viewing something that is naked eye visible, just select that object, and when the telescope stops sewing it will be in the ballpark. Manually slew the rest of the way, and it will track reasonably well.

[RobbW]

Actually, mine is an older model with 130mm diameter and 1020mm length. It was missing the finder scope, so I picked up a TruGlo red-dot scope from Cabelas and glued it on. Calibrated it and it works perfectly!

Unfortunately, I was not able to get out on Saturday night. Fortunately, it was because my wife and daughter managed to get rebooked on a flight for the same day.

[Chicago Astronomer - Astro Joe]

50 Mw Laser Repair and Alteration
24 April 2010

My 50 Mw raw Chinese green laser has been of great value since I got it recently, pointing to this and that - to the delight of many.

But I had a near tragedy and almost had a broken laser...

Some background first....

The laser had a push button momentary on & off. One had to keep the button depressed and really no big deal, but I had desires to attach it to my telescopes as a pointer. The momentary button would create a problem - and I didn't want to deal with an auxiliary collar to keep the button down.

I desired a switch that would stay on...and this near failure turned into a great opportunity for an upgrade.

I didn't take pics of the procedure, as I was frustrated and angered at this project - but I should have taken some regardless...

Whilst dining with fellow astronomers after a session, we were discussing our lasers and I took mine apart to show the contents. Really just a small circuit board attached to the main emitter and the aluminum case. The only problem was....that I could not get the micro switch properly seated with the button. I put it all away in my pocket disassembled and worked on it the next day.

No matter what I did or manipulated the micro switch, (which was attached directly to the small circuit board), I could not fit it along with the button. And with all the fiddling around...one side of the soldered terminal of the micro switch came loose.

Oh great...

Two problems now.

I soldered the terminal back and attempted to again, fit the assembly back into the tube, but having the same problem...and then...tragedy.

The micro switch completely detached from the circuit board...taking with it - some of the printed circuit...

Incredible...

Now, this cool laser was under $30.00 delivered and easily replaced...but it would be a shame to not try and repair it...despite the aggravations it would create for me....which would try my patience throughout the procedure.

I tried to solder back the micro switch, but to no avail. Two paths were now destroyed and it wouldn't take, so I jumped the gap with wire - soldering it and making it now, permanently on. I needed to interrupt the power somewhere - experimenting here and there..and every once in awhile, the fiddling would tear the jumper wire off the circuit - and with it - some more of the printed circuit path. #shootme#

d**n!

Re-soldering it a few more times, I finally decided to install a switch at the tail end of the tube. (This laser is powered "back wards", with the positive at the bottom and the body of the laser as the conduit. The negative is directly connected to the small circuit board via a spring.)

I keep everything and looked for a suitable switch. I found some, but they were all too bulky and large. I was going to use a mini slide switch, but waited until I went to Radio Shack to see what they had. I got a mini throw/two pole switch that would work just fine.

Now, how in the hell to install it.... #dunno#

I drilled the bottom cap of the laser to accept the base of the new switch. It was a tight fit and I thought some epoxy would secure it. For the connections, I used the base of a in-line fuse holder to act as the positive + connection and interrupting the flow of electrons to the body with the switch. With wires hanging about, I tested the set up...and it worked!.... ;D

Now, that I have the proper connections established...how to secure everything. At this time, I was too tired and aggravated with the d**ned laser...I closed up the workshop and left it for another day.

With a fresh mind and attitude, I re-addressed the situation.

The switch, (with a boxy base), would not remain secure in the elongated opening I created in the base cap of the laser, breaking the positive + flow connection. And again....the wire jumping the broken paths on the circuit board came loose...taking more path with it. And with one more detachment, I would no longer have anything to solder on to. So close...so d**ned close!

Testing the set-up again and wires hanging about - the laser was still alive and the switch worked beautifully.

The diameter of the tube was almost the same size of a .096 eyepiece barrel. I could use the barrel to tightly hang on to the new switch nicely. So....looking through my collection of spare telescope parts, I came across a few old .096 eyepieces. It's a shame to destroy a good eyepiece, so I searched for the worst of the bunch. A junky SR 4mm would see new useful life...and besides, it had some bad aberration.

I unscrewed the lens holder and popped out two tiny glass lenses, saving them. I had to Dremmel a bit the underside of the eyepiece cap to fit the base cap of the laser. After which, I had a good fit and Crazy Glued it to the eyepiece. Then, slipping the switch through the eyepiece hole....it all fit perfectly!

Tightening it with the hex hold down nut, it was solid. I screwed the new assembly on to the laser, but it didn't work. Something got loose...I hoped it wasn't the circuit board...

I added some more wire to the second pole of the switch, making solid contact all around the boxy base to the base cap.

Now, again screwing the cap back on to the laser....Yay....it works!..... #Yay#

With a solid feel and in all directions...the laser remained on and bright...better than what it was originally. Time for dinner, then some tests.

It started to drizzle in Chicago, but I took out the new and improved laser and found something pecular...

It was still as bright, but now...I was getting a double beam - slightly off-set from each other...

Something got bumped while fiddling around with the inner workings of this raw power Chinese laser. I was kinda disappointed, as I wanted it to be a pinpoint beam. I took off the top of the laser and the optical assembly rotates - one brass mini tube inside of another. I rotated the the assemblies, (using a jumper wire for the circuit), and it did seem that rotating the tubes would converge the beams...but I was afraid I would screw something up and twist something off.

Observing the beam, it seemed better now.

And with it working solidly now, to have it break by me tweaking it, would be so disheartening. So I let it be.

But....

I kinda dig it this way.

A comparison with the old and new beams....



It points to a slightly larger area - like space car headlights - quite unique!

A near tragedy averted and I got what I desired in the first place....a permanently on or off switch. Things happen for a reason...

It was well worth the aggravation and time. I will get another one, but the satisfaction of salvaging and improving the laser is cool... ;D


--

(I attached the 50 mW Raw Chinese power gree laser on to the C5 SCT...

astronomer.proboards.com/index.cgi?board=Equipment&action=display&thread=2704

Now, to attach it to the C11 SCT...! )