Never look at the Sun without certified eclipse glasses (ISO 12312-2). Sunglasses are not safe. Never use binoculars, telescopes or cameras without a proper solar filter.
Only during totality, and only inside the path of totality, can you look without glasses. An adult should tell you when to put them back on (at the first bead of light). Annular and partial eclipses are never safe to look at without glasses.
This page is a simulation - it is a safe way to look. The filter view shows what certified glasses show you.
Angular diameter of a sphere:
The Sun is about 400 times wider than the Moon and about 400 times farther: the two discs look almost the same size.
At the mean Moon distance the umbra tip does not quite reach you (L is shorter than the Moon's distance), so the Moon looks smaller than the Sun and a ring remains. Umbra diameter on the ground: D = 2 (R_m - d_obs (R_s - R_m)/d_s): about 162 km near perigee, negative (no totality) at mean distance.
D = 2 (R_m - d_obs (R_s - R_m)/d_s)
Here theta are radii-sums in degrees and omega is the Moon's speed relative to the Sun as seen from your place (typical 0.28 to 0.55 deg per hour, model). The model keeps omega constant and the motion straight: no path curvature, no refraction.
The Sun's edge is darker than its centre (limb darkening). Even when 99 % of its area is hidden, the visible edge still gives about 0.6 % of the light, about 600 lux: still daytime. Only in totality does it drop to about 1 lux (model; real values 0.1 to 10 lux).
The Moon's edge has mountains and valleys of about plus or minus 2 km, which is plus or minus 1.07 arcsec at 384 400 km. Just before and after totality, sunlight passes through the valleys as separate beads. A bead lives about 1.07 arcsec / 0.5 arcsec per s = 2 s. The Limb macro view draws a synthetic (random, seeded) lunar profile to scale; the last bead plus the first glimpse of corona is the diamond ring.
The corona is the Sun's thin, hot outer atmosphere, about a million times fainter than the photosphere (about 10^-6) - visible only when the Sun is hidden. Its shape follows the magnetic field and changes with the 11-year cycle; this corona is a model, not a photograph of a particular eclipse. Prominences are pink hydrogen-alpha loops.
Never look at the Sun without certified eclipse glasses (ISO 12312-2). Only in totality, only inside the path of totality, and only when an adult says so.
Pre-rendered illustration (Blender Cycles): sky and landscape plates, corona, prominences. Computed live: discs, contacts, area covered, daylight, temperature, beads, glare and every number. Lighting plates are blended by the computed daylight; brightness of the plates is partly adapted to look natural. Typical/model values: limb darkening u = 0.6, omega 0.25 to 0.55 deg/h, totality daylight about 1 lux, air-temperature drop up to 3 C with a 10-minute lag, coronal brightness about 1e-6. Dated presets are rounded public figures fitted to this simplified model - not an ephemeris; the Besselian-elements lab is the next step. This view uses a 2D canvas compositor (a departure from the usual Three.js stack, fine for a pre-rendered scene).
Independent numerical checks that do not reuse the simulation's code:
Besselian elements, path on the globe and a check against ephemeris data. Not affiliated with any space agency or observatory.