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ONSET

2020-01-17     [ Print ]

The Optical and Near-infrared Solar Eruption Tracer (ONSET) was constructed by Nanjing University in cooperation with Yunnan Astronomical Observatory. It consists of four tubes, which allow the quasi-simultaneous observations of the Sun in four wavebands, He I 10830 Å, Hα, and 3600 Å and 4250 Å continua, with either the full Sun or the partial Sun mode. 


The ONSET consists of four tubes: (1) a near-infrared vacuum tube, with an aperture of 27.5 cm, operating at the He I line center and wings up to 10 830 ± 2.5 Å with a full width at half maximum (FWHM) of 0.25 Å; (2) a chromospheric (Hα) vacuum tube, with an aperture of 27.5 cm, working at the Hα line center and wings up to 6562.8±1.5 Å with an FWHM of 0.25 Å; (3) a WL vacuum tube, with an aperture of 20 cm, working in either the 3600 Å or 4250 Å continuum with an FWHM of 15 Å; and (4) a guiding tube.