September 14, 2026: During summer shutdown 2026 restart, it was discovered that the PEPSI SX PFU side was suffering from severe vignetting despite attempts to realign with the M3 on-sky.  The cause was tracked down to index-matching oil in between some of the optical elements leaking into an airgap, causing elevation-dependent vignetting.  This was first noticed in Feb. 2026 when it wasn’t as severe, after which a realignment in June 2026 seemed to have solved the issue.  A fix is currently being planned to happen very soon, after which it will take appx. 1 week to complete the repairs.  These repairs will involve removing, disassembling, cleaning, reassembling, and realigning the PFU entrance optics.  We appreciate your patience as we work to resolve this issue.