Rho Ophiuchi Again!
More experiments with deep sky targets! This is a stack of 4 shots, each 12 minutes at f/4, ISO400. Sigma lens, Celestron CGEM2 mount with a ZWO guide camera for autoguiding. I tried at f/2.8 but I did notice just a little coma which seems gone at f/4. I don't know how long an exposure I can get without issues yet! This one was processed with a Photoshop star reduction technique, not something I normally like, but I l don't mind this!
Rho Ophiuchi Again!
More experiments with deep sky targets! This is a stack of 4 shots, each 12 minutes at f/4, ISO400. Sigma lens, Celestron CGEM2 mount with a ZWO guide camera for autoguiding. I tried at f/2.8 but I did notice just a little coma which seems gone at f/4. I don't know how long an exposure I can get without issues yet! This one was processed with a Photoshop star reduction technique, not something I normally like, but I l don't mind this!