The Okayama Astrophysical Observatory 188-cm reflector telescope primary mirror realuminization project has long been one of the signs of early summer in Okayama Prefecture. The staff involved in the realuminization works has changed greatly over the course of the more than 50 years since it started in 1960. But, this time like always, there is the commitment to accomplish the project safely and the perseverance to face the task of making the mirror sparkle for another year. This is what supports Okayama Astrophysical Observatory's shared use.

188-cm Reflector Telescope Primary Mirror Realuminization Project

Every year at the start of June, about the time that the summer rains arrive in Kamogata, staff members gather together to renew the old aluminum coating on the 188-cm reflector telescope primary mirror. At times, NAOJ relies on staff from other positions. The staff is divided into 3 groups: a group for disassembly to remove the primary mirror from the telescope; a group to clean away the old aluminum surface; and a group to carry out the realuminization on the cleaned primary mirror. The groups cooperate as work proceeds. All of the tasks require long periods of standing and physical labor. Because it requires muscles not normally used, everyone suffers muscle soreness. So, everyone is relieved when we see the beautiful mirror emerge from the vacuum chamber just as we hoped. That instant makes all the hard work worthwhile. The shiny mirror is returned to the telescope very carefully. Next year, the process will start again from here.

In the upper left, the pale-blue light rising in the north-east is Vega in the constellation Lyra. By dawn, the early spring constellations are reaching high overhead.

Watching over the course of one night, we understand that the North Star also traces a small arc centered on the north celestial pole.

Author: Hideyuki Izumiura (Okayama Astrophysical Observatory)