HI all, my first post over on this side as I wanted to ask about something strange in my image from last night. A couple of weeks ago I shot 4 hrs of OIII data on SH2-308 and had billions of stars but no nebula. I figured I may have loaded my new filter wheel with OIII and SII switched so last night I went out for a few test subs using the "supposed" SII filter.
As a test image to diagnose the fact that I had the 2 filters switched with each other in the software, it is 16 frames of 5 minutes (ASI1600mmm Pro) at unity gain with 5 darks. OK I have a nebula so problem solved.
Anyway, after processing the image and looking over it, I see what appears to be a little bubble like object just to the lower left of the nebula. I have checked various other images of this object including some done as late as January and February this year so I pass it over to you guys to possibly explain it. I know the larger dimmer spot could be a dust mote as I didn't shoot any flats, but what do you think the smaller, brighter blob is that makes the whole thing look like a bubble?
Higher res
here