| 摘 要： | As one of the three payloads for the Advanced Space-based Solar Observatory(ASO-S) mission,the Lyman-alpha(Lyα) Solar Telescope(LST) is composed of three instruments: a Solar Corona Imager(SCI), a Lyα Solar Disk Imager(SDI) and a full-disk White-light Solar Telescope(WST). When working in-orbit, LST will simultaneously perform high-resolution imaging observations of all regions from the solar disk to the inner corona up to 2.5 R_⊙(R_⊙ stands for the mean solar radius) with a spatial resolution of 4.8′′and 1.2′′for coronal and disk observations, respectively, and a temporal resolution of 30 – 120 s and 1 – 120 s for coronal and disk observations, respectively. The maximum exposure time can be up to20 s due to precise pointing and image stabilization function. Among the three telescopes of LST, SCI is a dual-waveband coronagraph simultaneously and independently observing the inner corona in the HI Lyα(121.6±10 nm) line and white light(WL)(700±40 nm) wavebands by using a narrowband Lyα beam splitter and has a field of view(FOV) from 1.1 to 2.5 R_⊙. The stray-light suppression level can attain10~(-6) B_⊙(B_⊙ is the mean brightness of the solar disk) at 1.1 R_⊙ and ≤5×10~(-8) B_⊙ at 2.5 R_⊙. SDI and WST are solar disk imagers working in the Lyα line and 360.0 nm wavebands, respectively, which adopt an off-axis two-mirror reflective structure with an FOV up to 1.2 R_⊙, covering the inner coronal edge area and relating to coronal imaging. We present the up-to-date design for the LST payload.
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