wallflash Posted March 2, 2018 Share Posted March 2, 2018 I am looking to buy an inexpensive green laser pointer to take camping and use to help show my grandson the constellations . In reading on them I have read that some cheap ones can emit dangerous levels of infrared radiation. In just browsing there looks to be some decent ones in the $50 range , if these are not the ones being referred to as dangerous. Any recommendations on a known safe laser pointer in the $50 range that are decent enough to point out constellations on a clear night? Link to comment Share on other sites More sharing options...
John Cuthber Posted March 2, 2018 Share Posted March 2, 2018 If you are going to point them at the sky, it won't matter if they emit infrared. Link to comment Share on other sites More sharing options...
wallflash Posted March 2, 2018 Author Share Posted March 2, 2018 (edited) 28 minutes ago, John Cuthber said: If you are going to point them at the sky, it won't matter if they emit infrared. Im not sure what their concern is, the object being pointed at or the users hand holding it. http://www.skyandtelescope.com/observing/some-pointers-on-the-use-of-laser-pointers/ Under a "buyer beware" warning, they write A second concern emerged even earlier, in 2010, when four NIST researchers found that poorly made green laser pointers can emit harmful levels of infrared radiation. These laser pointers generate a collimated beam of infrared energy that's converted to green light when it passed through a special crystal. In most units, a combination of coatings and filters keeps all the infrared energy confined. But the researchers found that really inexpensive green lasers can also lack an infrared filter altogether. One tested unit was so flawed that it released nine times more infrared energy than green light. Edited March 2, 2018 by wallflash insert quote Link to comment Share on other sites More sharing options...
John Cuthber Posted March 2, 2018 Share Posted March 2, 2018 If you are pointing out constellations... The only bit of the user that is particularly vulnerable is their eyes. Link to comment Share on other sites More sharing options...
swansont Posted March 4, 2018 Share Posted March 4, 2018 IIRC the danger lies in the fact that the green light is not collinear with the IR light. So the pointer could be pointed in your direction but not right at you, and you could be in danger. Pointing it at the stars should not be a problem. Link to comment Share on other sites More sharing options...
Externet Posted March 4, 2018 Share Posted March 4, 2018 There is maaany in the market, well under your price range : ----> https://www.aliexpress.com/item/Green-laser-Astronomy-Puntero-Laser-5MW-532nm-Focus-Visible-Green-Laser-Pointer-Pen-Beam-Light-Powerful/32844618587.html?spm=2114.search0104.3.29.440040fdnjTe4m&ws_ab_test=searchweb0_0,searchweb201602_4_10152_10151_10065_10344_10068_10130_10324_10342_10547_10325_10343_10546_10340_10548_10341_10545_10084_10083_10618_10307_5711211_10313_10059_10534_100031_10103_10627_10626_10624_10623_10622_10621_10620_5722415_5711312,searchweb201603_38,ppcSwitch_5&algo_expid=59d6670d-7480-4d22-918b-cd3746777059-4&algo_pvid=59d6670d-7480-4d22-918b-cd3746777059&transAbTest=ae803_5&priceBeautifyAB=0 Link to comment Share on other sites More sharing options...
John Cuthber Posted March 4, 2018 Share Posted March 4, 2018 r buy any laser you like, but put a filter over it https://www.ebay.co.uk/i/401413220438?chn=ps&adgroupid=57477863008&rlsatarget=pla-413073660608&abcId=1133926&adtype=pla&merchantid=119067196&poi=&googleloc=9046552&device=c&campaignid=1058613747&crdt=0 Link to comment Share on other sites More sharing options...
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