I made this cider about 18 months ago and checked the airlock regularly so it never ran out of vodka. Does this picture show a ring of mold in the headspace? If so, are there any steps to take when bottling to save it?
It's too hard to tell what it is from the picture. Probably dried yeast. I wouldn't worry unless you have something unusual floating on the surface of your cider.
I moved the carboy very gently from the closet to a nearby table to take a closer look. The sediment had dissolved just from that handling - picture below. I'm guessing it's just yeast from racking after fermentation was complete in the larger carboy. There was nothing floating on the surface even when it was in the closet. I will bottle and hope for the best.