香港天文論壇

Images in H-alpha (colour)

2021 January 17 Sun - prominences on the SW solar limb The huge prominence is fairly quiescent although some slow mass motion ma be in progress. Sunspot count: group=2, sunspots=7, R=27 For H-alpha images: Telescope: Lunt LS50T with B1200 blocking filter + 2X barlow Camera : ASI174MM and ASI174MC ex...

Images in Ca-K

Images in H-alpha (monochrome)

2021 January 17 Sun - prominences on the NW solar limb The huge prominence is fairly quiescent although some slow mass motion ma be in progress. Sunspot count: group=2, sunspots=7, R=27 For H-alpha images: Telescope: Lunt LS50T with B1200 blocking filter + 2X barlow Camera : ASI174MM and ASI174MC ex...

Images in Ca-K

Images in monochrome

2021 January 17 Sun - eruptive prominences on the E solar limb These are small but active prominences. Sunspot count: group=2, sunspots=7, R=27 For H-alpha images: Telescope: Lunt LS50T with B1200 blocking filter + 2X barlow Camera : ASI174MM and ASI174MC exposure: 50.0 ms (monochrome), 35.0 ms (col...

Images of AR12796 in colour

Images of AR12796

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2021 January 17 Sun - solar surface in H-alpha with AR12796 AR12796 is still active with flares and filaments. The sunspots, however, become smaller. sunspot count: group=2, sunspot=7, R=27 Telescope: Lunt LS50T with B1200 blocking filter, and 2X barlow Camera : ASI174MM and ASI174MC exposure: 2.0 m...

2021 January 17 Sun - solar surface in Ca-K, with AR12796 AR12796 is still active with flares and filaments that are visible in Ca-K. However, the sunspots are not visible. sunspot count: group=2, sunspot=7, R=27 Telescope: Sharpstar AL-80 II, 8 cm f/6.25 APO refractor Camera : ASI174MM focal length...

2021 January 17 Sun - solar surface in white-light, with AR12796 and possible AR12797 This supplementary observation is carried out to observe the new possible AR12797 which turned to the front side this morning, but not noted in my morning observation. sunspot count: group=2, sunspot=7, R=27 Telesc...

2021 January 17 Sun - AR12796 and possible AR12797

On the SE limb, 2 huge sunspots show up this morning, at (S18E88).
Together with AR12796, the solar disc will become more interesting.

Sunspot count: group=2, sunspot=7, R=27

White-light image from SDO, taken at 04:28 UTC.