Relating to or performed with a helioscope; capable of viewing or examining the sun safely without harm to the eyes.
From 'helioscope' plus suffix '-ic' (relating to), describing instruments and methods for sun observation.
Helioscopic instruments use special filters and projection methods so astronomers can study the Sun's surface without burning their retinas—it's basically the difference between looking at the Sun directly (ouch!) versus safely through filtered light!
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