Wavelength
656.28
28°14′N 16°38′WContinuous record since 1874
Institute of Solar Memory
one star, observed without interruption
Every clear morning since the third of April, 1874, this institute has made one photograph of the sun. Nineteen keepers. Fifty-four thousand plates. A single unbroken sentence about a star that does not know we are writing it.
Current observation
Aperture 254 mm
Hα 656.28 nm
Exposure 1/2000 s
Hα 656.28 nm
Exposure 1/2000 s
We do not study the sun. We remember it, one plate each day, for a hundred and fifty years, so that some later eye might read what ours could only record.
Keeper’s note, 1949
“The instrument does not care whether anyone is watching. That is the whole of its virtue, and most of its cruelty.”
A. Verdú, seventh keeper
§ 02The Instrument
§ 03The Signature
Sunlight arrives complete and leaves with pieces missing. Every dark line is an element standing between the star’s core and this island, taking its portion of the light.
Drag across the band to inspect a line. With sound enabled, each absorption is voiced at a frequency scaled from its wavelength: the spectrum, heard.
Plate 54 118 · Hα quadrant · 11 s exposure
Dispersion 0.42 nm · mm⁻¹
Element
Hydrogen
Fraunhofer
C
Depth
0.86
◀ Drag to scan ▶Nine principal lines catalogued
§ 04The Field
Nothing here
is solid.
What looks like a surface is a lid of boiling gas one thousand kilometres thick, held in shape by a magnetic field that turns itself inside out every eleven years. The loops you see are not drawn. They are traced, one particle at a time, along the field as we last measured it.
Move your cursor through the field
Photosphere5 772 K
Corona1.9 MK
Field strength, spot0.31 T
Rotation, equator24.5 d
Rotation, pole34.0 d
§ 05The Cycle
Two hundred and seventy-six years of counting spots, and the star keeps almost the same time: eleven years, give or take, forever.
The Institute’s own plates begin at the vertical rule. Everything to its left we inherited from other people’s patience.
1859 · 96 spots
Smoothed monthly number
Cycle maxima
Institute record begins 1874
§ 06The Archive
Each plate is a single morning. Silver, gelatin, glass, and one star that never sat still for any of them.
§ 07 · 09 JULY 2028 · 04ᵐ 11ˢ
Totality
In two years the moon will cover this island completely, and for four minutes and eleven seconds the corona will be visible to the naked eye. We have been getting ready for a hundred and fifty years.