path of totalitycontour = % of sun coveredthe shadow, right nowyou — tap the map to move
umbra + penumbra conesthe shadow on the surfaceyoudrag to orbit · wheel / pinch to zoom
The green ring is the aurora, right now (NOAA’s forecast for the next half hour). The sun blows a thin wind of charged particles past us all the time. Earth’s magnetic field turns most of it away — but near the magnetic poles the field lines plunge into the ground, and particles ride them down into the air about 100 km up, where oxygen glows green. So the aurora is not a patch in the sky: it is a permanent ring round each magnetic pole, always there, mostly too far north to see. When the wind’s own magnetic field tips south (that is the Bz number) it links up with ours, far more energy gets in, and the ring brightens and swells towards the equator — that is the night it reaches you. Drag the globe: the ring is off-centre from the axis the earth spins on, because the magnetic pole is in the Canadian Arctic. Your pin is the white dot.
illustrative scale
Sun and moon sit along their true directions for this moment, the earth carries its true rotation, and the shadow lands at its true position; distances and sizes are compressed for clarity (at true scale the moon would be sub-pixel).
W
°
°% lit
sun path · direct sun heresun behind the skylinemoontap = stand there · drag · pinch / wheel · two fingers or right-drag to turn
Space weather: NOAA SWPC, read live — this is the one view that needs a connection. Where it sits in your sky, the darkness, the moon and your horizon are computed here, for your coordinates. Set your blocked horizon under the location panel: from Britain the whole event lives in the bottom ten degrees.
MAXIMUMNOW——
Location + Date
Fine tunelat, lon, date, horizon
0.0°
Eclipse at this location
right now— UTCsun — alt / — az— covered
Photographer mode
Your camera
drives the framing, the exposures and the planmm
mm
Framing
Exposure — Espenak t = f² / (ISO × 2^Q)
These are starting shutter speeds for each stage of the eclipse at the aperture and ISO you set above — set the shutter, shoot, then judge the result. Q is just a brightness number for the subject: each step of Q is one stop, and a bigger Q means a brighter subject and a faster shutter. The corona spans many stops at once, so no single value catches it all.
Corona spans a huge dynamic range — bracket wide (±3 stops or more around each value) and merge later. These are starting points, not answers.