Thanks, you're right, I don't have very good calibration. I'll do that next time I'm out. But I don't think that it's related to the issue that I'm seeing. I generally use similar settings for the calibration, and I've very reliable, and good guiding in the past. This spike is new, I don't think that I've ever seen it before. Tonight I'll be trying things out using the guide scope instead of the OAG. If the issue is still there, then I can eliminate possible issues with the SCT like mirror flop or some sort of looseness. If that fixes it, then there might be something going on with the SCT, or image train on the SCT.?
