Source :http://www.atoptics.co.uk/Nacreous Clouds :http://www.sundog.clara.co.uk/highsky/nacim0.htmSolar Halos :http://www.sundog.clara.co.uk/halo/dogim3.htmhttp://www.sundog.clara.co.uk/halo/dogim4.htmIridescent Clouds :http://www.sundog.clara.co.uk/droplets/irid1.htmGlories :Comment too long. Clickhereto view the full text.