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Solar eclipse observation: some simple devices.

The terrestrial solar irradiance is evaluated in view of the energy absorbed by the retina and the blue light hazard. The evaluated irradiance is compared with the known safety standard, to determine the safety requirement of solar eclipse observation devices. Simple devices are then proposed. The first is a folded pinhole camera, giving a magnified sun image from a relatively small box. The second is a pinhole projector, used to display the image in a large room, while the third is a compact multimirror periscope enabling one to see the sun sharper than with a pinhole camera.