香港天文論壇

2021 February 21 Sun - prominences on the SW solar limb This prominence is formed from part of the dark filament that has moved off-disc. Sunspot count: group=1, sunspots=2, R=12 For H-alpha images: Telescope: Lunt LS50T with B1200 blocking filter + 2X barlow Camera : ASI174MM exposure: 20 ms For Ca...

Images of AR12803

Images of AR12802

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2021 February 21 Sun - solar surface in H-alpha, with AR12802 and AR12803, and huge dark filaments AR12802 is located at (N18W68) this morning. There is not much visible feature. AR12803 is today located at (N21E49). Bright intense flares are present, so are filaments. The sunspots are not observed ...

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Images of AR12803

2021 February 21 Sun - solar surface in Ca-K, with AR12802 and AR12803 AR12802 is located at (N18W68) this morning. Not much is visible except for a few plages. AR12803 is today located at (N21E49). Bright flares are visible, so are plages. Only 2 sunspots are visible. sunspot count: group=1, sunspo...

Images of AR12803

2021 February 21 Sun - solar surface in white-light, with AR12802 and AR12803 AR12802 is located at (N18W68) this morning. No sunspot is visible. Faculae are visible. AR12803 is today located at (N21E49). 2 sunspots are visible. The larger sunspot from yesterday is now a bipolar Class-C group, with ...

Images in H-alpha

2021 February 20 Sun - prominences on the NE solar limb Sunspot count: group=1, sunspots=4, R=14 For H-alpha images: Telescope: Lunt LS50T with B1200 blocking filter + 2X barlow Camera : ASI174MM exposure: 25 ms For Ca-K images: Telescope: Sharpstar AL-80 II, 8 cm f/6.25 APO refractor Camera : ASI17...

Images in H-alpha

2021 February 20 Sun - prominences on the SE solar limb Sunspot count: group=1, sunspots=4, R=14 For H-alpha images: Telescope: Lunt LS50T with B1200 blocking filter + 2X barlow Camera : ASI174MM exposure: 25 ms For Ca-K images: Telescope: Sharpstar AL-80 II, 8 cm f/6.25 APO refractor Camera : ASI17...