This is how I manage to get see and photo so many different species of moth in my garden. This is Mk III of my homemade moth trap, utilising 2x 20w blacklight bulbs which do not cause light nuisance issues with the neighbours as some of the more powerful mercury vapour lamps do. You can buy already made moth traps online, but they can be expensive.
You can see more clearly where I have removed one half of the lid of this relatively cheap plastic storage box to show how I access the moths the next morning and the egg boxes which they rest inside. I fixed a timber framework to hold the lighting above the funnel (one light worked okay originally, but two seems better) and then cut the lid in half and around the framework. I fixed a plastic party plate above to help direct the moths between the bulbs into the funnel, and this also acts a rain protector just in case there is any drizzle. But I always check weather forecasts for dry nights. Warm and still nights are usually the best. The bulbs are fixed into two batten holders which are wired to a plug. It is always advised to plug into an RCD socket so that if there are any issues with the electrics it should cut out. Please note that any electrical work should be done by a competent person.
The full set-up at the side of my shed can be seen here. The cheap plastic shower curtain reflects the UV light and some moths will settle on it and around it, sometimes around the corners out of the light. A white bedsheet will do just as well. I sometimes leave the outside shed light on in conjunction with the blacklights, and this appears to increase numbers slighty. You can set the trap up anywhere in your garden and without the shower curtain or white sheets, and you should still get a fairly decent catch if the weather conditions are favourable. I have it elevated for convenience’s sake, but it can be placed on the ground, which some trappers prefer to do.
All moths are released unharmed into a safe environment once they have been checked and photographed. I do not trap frequently, and very rarely on consecutive days, as this my disrupt their feeding and mating cycles.