New low temperature laser

[Tweedledee]

After seeing Robs video, I just had to do a little test. I have some of the red laser protection glasses shown in that video, but had only ever used them to help get quickly dark adapted inside the house prior to an observing session, for which they are excellent. I had never thought of seeing how they attenuated the laser light.

 

So I went into the garage and switched off the lights and took a phone pic of my laser hitting the garage door and then the same pic with the red glasses over the camera lens and the laser spot nearly disappears. In the bright lounge I did the same thing with and without the red lens and the dot is hardly seen. The same effect happens when wearing the glasses, so they really are very effective at dimming the green laser light, The light from the laser is more dazzling to the eye than on the pics...

 

 

 

 

Edited July 2, 2016 by Tweedledee

[Tweedledee]

I received the new low temperature laser on Tuesday.

 

As soon as I got it I put it in the fridge with a thermometer (as you do ). After a couple of hours with the thermometer reading +5 degrees C, the laser still worked fine. I then put it in the freezer with the thermometer. After just over an hour the thermometer read -12 degrees C and the laser still worked fine. I checked it several times over the next hour and it still worked.

 

Below are some photos and details of further testing from later on Tuesday night.

 

The first shows my existing laser below the new laser...

 

The second photo shows a comparison of the dots produced by both lasers on my garage door with the lights on. The fainter green dot to the left is the low temperature one...

 

The third photo shows a comparison of the dots produced by both lasers on my garage door in the dark. Note that the line of the beam is not visible from the dimmer low temperature laser...

 

The fourth photo was taken outside after dark with a clear sky at about 10.50pm with both lasers pointing up towards the Vega. No beam is visible at all from the low temperature laser. All photos were taken with my Samsung phone. I can confirm that the beam from my laser actually seems substantially brighter as seen by a dark adapted eye than in the photo, but still no line from the low temperature laser was visible by eye...

 

I checked the voltage of the supplied batteries on a multimeter after these tests and found they were still running at an acceptable 1.2 volts each. I replaced the batteries with fresh new 1.5 volt ones and noticed no difference in brightness and still no beam visible from the new laser.

 

I conclude that the new laser certainly works at temperatures down to at least -12 degrees C which my existing laser will not do. This seems to be the only laser that does actually work at low temperatures, but the line of the beam is not bright enough to be seen at night.

 

The new laser will be returned and I'm hoping that they will produce a higher power version.

 

Oh well, it was worth a try.