Development of PLANETS telescope and visible-infrared spectrometer for monitoring of planetary and exoplanetary atmospheres

We report the current status of small-telescope activities and the 1.8-m aperture telescope PLANETS project at Haleakala dedicated to planetary and exoplanetary observations. Continuous monitoring is essential to understand the planetary atmospheric phenomena, and therefore, own facilities with even small- and medium sized telescopes and instruments are important. On the summit of Mt. Haleakala, Hawaii, we are operating a 40 cm (T40) and 60 cm (T60) telescopes for measuring faint atmospheric features such as Io torus, Mercury, and so on. It has uniquely provided long-term Io torus activities for more than ten years. T60 is now observing planetary atmospheres in visible and infrared ranges. The polarization imager DIPOL-2 is also installed to measure the weak polarization of exoplanetary light. In addition, we are carrying out a 1.8-m off-axis telescope project PLANETS at Haleakala. This project is managed by the PLANETS Foundation (www.planets.life) is an international collaboration of several institutes from Japan, USA, Germany, Brazil, and France. This off-axis optical system enables very low-stray light contamination and high-contrast in data, i.e., high dynamic range. It will achieve unrivaled scientific capabilities on coronagraphy and polarimetry, aimed at detecting exoplanet reflected light and tenuous planetary exo-atmospheres in the Solar system. The main mirror is Clearceram ZHS with a diameter of 1850 mm, which is now on the final polishing process. We completed the telescope design and wind analysis of the mechanical support and tracking. The «split-ring» mount is so stiff that it has a first vibration mode above 50 Hz.