hobby #183
Spectroheliography
Building a spectroheliograph to photograph the Sun in a single narrow wavelength — scanning the projected solar image across a spectrograph's entrance slit, isolating one emission line (the calcium K-line at 393.4 nm or hydrogen-alpha at 656.3 nm) with a ruled diffraction grating, and reconstructing a monochromatic image line-by-line as the slit sweeps. The result reveals plages, filaments, and chromospheric mottling that never show up in white light.
Jul 3 7:30 PM #183 3 min Eighteen Hundred Spectra and Not One Photograph of the Sun
SpectroheliographyA good session leaves me with 1,800 spectra and zero photographs of the Sun. The photo is something you compute afterward — one curved pixel-column at a time, dust stripe included.
code-a-day tied to this hobby
- One Wavelength at a Time: Pipelines That Filter Light Message-passing pipelines