My old club installed one at our primary observing site. I was never convinced of its effectiveness. You have to run it day and night (with propane cannisters) and of course the CO2 plume is affected by wind. My feeling was that a lot of mosquitoes who were attracted by the CO2 found me along the way. There are plenty of people who swear by these things. I swore at it. MC

Has anyone tried one of those CO2-emitting mosquito traps? While they are designed to collapse populations of extended areas over time, I have read that they are quite effective at immediate relief over smaller areas. I have thought of getting one for my backyard this summer. The units that combine a UV source with CO2 emission are said to be the most effective. The heat plume from the propane burner would be similar to that produced by a candle- probably not enough to degrade seeing unless you were right next to it. One of the smaller units could be setup in the general vicinity of a group of observers.