GeminiFocus July, 2015 | Page 16

Figure 6. GPI NRM “snowflakes” observed during the commissioning time in May 2015. Left: Raw data frame. Right: Power spectrum. Non-redundant Masking with GPI Commissioning of the Gemini Planet Imager (GPI) Non-Redundant Mask (NRM) mode was scheduled for late March, and coincided with the horrendous flooding event described below. Because of this, no data were taken. Since this mode was to produce some of the highest-contrast observations with GPI, we rescheduled a commissioning night in May. The team, led by Peter Tuthill and Alexandra Greenbaum, visited the telescope and obtained a night’s worth of useful data, which they are now working to reduce. Future users will need to become familiar with the “snowflake” patterns produced when the seeing is good and the NRM mask is in place; two samples of this effect appear in Figure 6. Figure 7. Aftermath of the major rainfall in Chile, March 2015 14 For the technically inclined, the raw image taken through the mask can be thought of as an interferogram — a pattern formed from fringes containing high spatial resolution; these cross the Airy disk diffraction pattern caused by the individual circular holes. The power spectrum image shows fringe power at 45 individual baselines; these correspond to each pair of holes in the mask and reveal the surprising degree of inherent order in the image. GeminiFocus Data Center Re-engineering Relatively unseen by the outside user, the summit data centers have been re-engineered over the past six months. The new data centers are split into hot and cold zones, producing significant energy savings. They also foster greater sustainability and cybersecurity. Destructive Weather Event in Chile Near the end of March, Chile suffered a freak storm that dumped many inches of rain on the high deserts and caused major flooding and destruction right down to the coast. Cerro Pachón was one of the affected areas. As a result, Gemini South lost power, communications, and nights of telescope time. Figure 7 shows some of the aftermath of the flooding. Thanks to the quick and effective work by the engineering staff, the telescope was back on line very shortly after the storm passed. July 2015