Lots and lots of dust bunnies
Pop off down to your local camera shop and pick up a bulb blower and from an art shop a very very very soft sable brush. Use the blower first to try to get the worst of it off and then gently dust the chip off with the brush. If you are not confident with using the brush, I use a pure cotton qtip moistened (not dripping wet) with 50/50 isopropyl alchohol and distilled water. This I then slide across the chip with an upward rolling motion to collect and lift any dust away. Avoid dragging across the chip surface. Important not to have the qtip too wet. You don't want water under the chip cover
Also check the rest of you glass element in the imaging train. Some of those dust bunnies look to be a fair way away from the chip surface. Are you using a barlow or Focal Reducer? Their surfaces will need cleaning as well using the same technique.