A friend of mine just bought a new Skywatcher 127 Mak Cas. We were outside testing it out last night. With an 8mm eyepiece we noticed that when an out of focus star is in the middle of the field the rings are perfectly concentric on one side of focus but slightly off center (slightly below center) on the other side.There is no observable image shift and both sides of focus were centered. The rings are round on both sides. Not oval. To us it's odd that one side would be okay but the other is slightly off instead of both being off center. The in focus image of a double star is perfect. Iota Cass was split perfectly and the "E" star in the Trapezium was easily seen so the alignment is apparently okay. This is not a serious problem but we are wondering why it looks like this. Any Ideas? Thanks
Edited by gfeulner, 08 December 2018 - 11:15 PM.