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Understand the choice between single-site and merged magnetogram data, optimal cadence selection, rotational smearing correction methods, and spatial resolution considerations for remapped images. Learn how to interact with SOLIS cadence, handle poles, line-of-sight projection, and missing data for creating synoptic maps.
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Single-site or merged? Single-site requires users to select. Merge has lower noise, may require site-specific correction to reduce jumps as stations change. At what cadence? 1 min – highest cadence, most noise. 3 min or 5 min – compromises. 10 min – lowest cadence, least noise, rotational smearing starts to be a concern. Rotational smearing correction? How? Rotation crosses 1 pixel at disk center in about 15 min. Remap and average in heliographic coordinates, transform back to sky. What temporal filter/averaging algorithm? Simple box car. Hathaway filter (Gaussian). Will need to specify width in any case. Sky-coordinate images
Same questions as for sky images: Single-site/merged Cadence Rotational smearing easy to deal with Temporal filter What spatial resolution for remapped images? Currently 0.2° What projection for remapped images? Currently longitude - sine latitude Remapped images
Single-site or merged? At what cadence Trade-off between effort and science: What’s rapid enough for space weather? 1, 2, 4, 8 hours? How to interact with SOLIS cadence? Identical times for comparison? Different times to fill in temporal gaps ? How to treat poles, projection of LOS, missing data? Synoptic Maps