Hi Ian
The best lamp for airrifles is the variable power, like the Deben mini pro with a red filter, you can put just enough power on to shoot so there's less chance of spooking the rats, a cheeper but not as good a way is from Deal extreme they do a ultrafire 501 r2 torch with a five mode switch its rated at 250 lumens at full power they cost about £11 then there's the cost of batteries e c t on top of that. The idea of you putting out the solar lights is a good idea in that it will get the rats used top a little light, there fore maybe allowing you to use a lowish powered lamp. Do you have any torch at al that you can put a bit of red bag/paper over just to try how jumpy the rats are, if there not too jumpy a red filtered gun lamp/torch should work. If say the rats are comming out from under a shed couldnt you put the solar lights around this hot spot, and bait it for a few days, even if this ment that you had to move the lamps to charge in a different position in the day time then put them back around the hot spot for when it gets dark, if you can just get enough light from the solar lights to see to shoot, the rats will eventully come out and feed on the bait, they might not do it first night though, if the solar lights dont give you enought light like this it will still help for you to use a low powered red filtered gun lamp/torch. You need bait that they cannot pick up and carry away ( peanut butter, runny cat food e c t ).

Dave (warbucks)