[PCG23-P04] Planetary and exoplanetary observations with the Haleakala telescopes and future 1.8-m off-axis telescope PLANETS
Keywords:planet, exoplanet, Haleakala, Jupiter, Mars, Venus
On the summit, our group is now operating a 40 cm Schmidt-Cassegrain (T40) and 60 cm Cassegrain (T60) telescopes. T40 telescope is mainly observing 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 range: MIRAHI is a newly developed mid-infrared heterodyne spectrometer. Vispec is a visible spectrometer with coronagraph to observe the Io's sulfur ion torus, Io's sodium cloud, and Enceladus torus. Further, the polarization imager DIPOL-2 is installed to measure the weak polarization of exoplanetary light. These activities are open to any possible collaborators. Our and guest investigators' observations are also linked to Mercury, Venus (Akatsuki), Mars (Mars Express, MAVEN) and Jupiter (Juno) missions.
In addition, we are carrying out a 1.8-m off-axis telescope project PLANETS at Haleakala, Hawaii. 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 exoatmospheres in the Solar system. It will have a Gregoian focus with a FOV of 6' (Fno=13) and a Coude focus with a FOV of 20'' (Fno=49). The main mirror is Clearceram Z-HS with a diameter of 1850 mm, which is now on the final polishing process. We have completed the telescope design and wind analysis of the mechanical support and tracking. The offaxis design is most efficiently contained in a 'splitring' mount. The mount is very stiff and has a first vibration mode above 50 Hz. The PLANETS telescope mechanical design should allow operation without a dome and external wind shielding up to windspeeds of 5m/s. The servo control on both axes will not require high gain and should result in image jitter of less than 0.4'' at frequencies less than 25 Hz during light to moderate winds (windspeeds less than15mi/hr). A bode plot of the proposed control system illustrates that unity gain is achieved beyond about 30 Hz.