when l did some test images of the Horsehead some time back l noticed what l thought was a stray light source causing an internal reflection and did'nt think much more about it.
after taking the Horsehead pics that l posted last week without a filter l thought the problem was as l stated stray light.
however after thinking some more l did some more test shots tonight with and without my Baader UHC-S filter and with the filter it is back, ignore the shots themselves as they are just to test my thoughts. all shots taken at iso 1600 for 90 sec.
is this a distance issue ( filter to focal plane ) or something else, any thoughts appreciated.
