sci23024 — Announcement

Gemini Mirror Status: May 2023

May 23, 2023

It is official — the Gemini North primary mirror repairs are complete and the mirror has been successfully recoated. The process of reassembling the telescope to return to operations is now under way. 

We are confident that all glass defects have been repaired and secured. The new lateral pad was installed at the end of March, and the new epoxy cured while the pad was held at a constant temperature and in a fixed, monitored position for two weeks. We have completed a final analysis of stress surrounding the newly attached lateral pad, and have performed a series of ‘pull tests’ on witness samples created with the same batch of epoxy. All of these tests indicate the Gemini North primary mirror is fully repaired. 

The newly recoated mirror was recently reinstalled in the mirror cell and the mirror cell was reinstalled in the telescope. Installation of the Acquisition and Guidance Unit and instruments will follow, with subsystems being thoroughly tested after a long period off sky. 

Our current plan is to start on-sky nighttime tests prior to a return to regular operations in the first week of June. To support community planning, we note that:

  • Director's Discretionary Time proposals should not request Gemini North observations that begin prior to 15 June.
  • Fast Turnaround proposals for Gemini North will be solicited for the 30 June deadline for observations beginning 1 August.

About the Announcement



Gemini North telescope - side view

International Gemini Observatory/NSF’s NOIRLab/AURA/J. Pollard