Premise: The Earth is motionless. The sun and all planets move around it. All observations support this premise. Fallacy: Observations only support the premise if you assume it's true.
Premise: The sun is powered by fusion. The process has been fully described by math models. Fallacy: Observations refute the premise.
Premise: The universe is governed entirely by gravity. All observations agree with predictions by theories. Fallacy: Predictions that don't work are ignored, and theories based on electric charge are much more reliable. (This one is a hoot because astronomers insist that electric charge only works in equipment specifically designed to use it, not in space.)