Instability Introduction

• Small Temperature Changes in ACS Components Cause Apparent Motion of All Detectors wrt Internal or External Optical Sources

• Specification is 10 mas peak-peak over 2 Orbits

• Several Distinct Phenomena Identified:

  • "Warm-up" Transients
  • ASCS Interface Plate Related Transients
  • "Rolling" Transients Associated with Room Temperature
  • Shifts in Coronagraph Location with Orientation Change and with Different Holding Fixture