It's that time of year, and one of my webcams caught a glimpse of some noctilucent clouds early this morning a couple of hours before sunrise. They were a bit low on the northern horizon, but quite bright. They sometimes make quite a striking subject for photography using a good SLR, because they often show lots of intricate detail against a darkish sky. There are a few photos of past displays in the gallery (http://gallery.orpington-astronomy.org.uk/thumbnails.php?search=noctilucent&submit=search&album=search&title=on).