M71 Globular cluster in Sagita.

M71. This globular cluster lies deep with in the constellation of Sagitta at a distance of about 13,000 light years . It shines at about magnitude six and is easily visable through a small telescope. I took this image using my ten inch F4.8 reflector , PHD auto guiding and an Atik 383L mono CCD camera . I captured five minute sub frames with matching dark frames. I also captured twenty flat field frames for each colour channel to reduce the effect of vignetting in the final image. The total exposure times was 40 minutes for each colour filter: