M5 in Serpens . June 5, 2006. 120 frames (exp. 2 seconds) were stacked with Registax. Left image: planetary nebula M57 (Ring Nebula, NGC6720) in Lyra . June 10, 2006. 105 frames (exp. 4 seconds) were stacked with Registax. M57 has a relatively high surface brightness of 17.9. See also this