The side facing the Earth carries the latest available image of the chosen channel (SDO/AIA and HMI, through Helioviewer): each pixel is mapped back onto the sphere by orthographic projection, with the orientation of the Sun seen from the Earth computed for the current instant (latitude B0 of the disc centre and Carrington longitude L0 of the central meridian, Meeus ch. 29; checked against the values published by the HEK, within 0.003°). Around the disc, the same image shows the low corona and, as an option, the LASCO C3 coronagraph the outer corona, as planes facing the Earth that fade out when the view turns away.
Elements are placed in heliographic Stonyhurst coordinates at the current instant. Those observed earlier (active regions surveyed at 0 h UT, flares, coronal holes detected a few days ago) are moved by the differential rotation of the Sun, 14.7° a day at the equator and 12.4° at 60° latitude (Howard et al. 1990): an element that went behind the limb appears on the far side, where it should be if it persists. CMEs are drawn in the plane of the sky with the angle and width measured by CACTus; their length assumes a constant speed. The magnetic connection follows the Parker spiral for the solar wind measured at L1 (ballistic mapping, Nolte and Roelof 1973).
The links offered for an element are the correspondence tests of the site that involve that phenomenon, with their verdict (clear link or inconclusive).
- Müller et al. (2017)
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Müller, D., Nicula, B., Felix, S., et al. (2017). JHelioviewer: Time-dependent 3D visualisation of solar and heliospheric data. A&A, 606, A10. Images: Helioviewer.org (ESA/NASA).
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Scherrer, P. H., Schou, J., Bush, R. I., et al. (2012). The Helioseismic and Magnetic Imager (HMI) Investigation for the Solar Dynamics Observatory (SDO). Solar Physics, 275, 207–227.
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Verbeeck, C., Delouille, V., Mampaey, B., & De Visscher, R. (2014). The SPoCA-suite: Software for extraction, characterization, and tracking of active regions and coronal holes on EUV images. A&A, 561, A29.
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Robbrecht, E., & Berghmans, D. (2004). Automated recognition of coronal mass ejections (CMEs) in near-real-time data. A&A, 425, 1097–1106.
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Licence : Published literature; cited - Howard et al. (1990)
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Howard, R. F., Harvey, J. W., & Forgach, S. (1990). Solar surface velocity fields determined from small magnetic features. Solar Physics, 130, 295–311.
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Parker, E. N. (1958). Dynamics of the Interplanetary Gas and Magnetic Fields. ApJ, 128, 664. Ballistic mapping: Nolte, J. T., & Roelof, E. C. (1973). Solar Physics, 33, 241–257.
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Meeus, J. (1998). Astronomical Algorithms, 2nd ed., ch. 29: Ephemeris for physical observations of the Sun. Willmann-Bell.
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