The Sun imaged in the near UV: Daystar Calcium H-line Quark vs Baader K-Line filter

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When I started observing the Sun on a regular basis, several decades ago, amateur astronomers were involved mainly in drawing and counting sunspots, in calculating the Wolf number and in following the evolution of solar cycles in white light. The “solar telescope” by definition was a small refractor with a … Continue reading

Rifrattore acromatico Skywatcher 150 f/5

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di Raffaello Braga In pochi settori dell’hobbistica circolano tante leggende metropolitane come in quello dell’astronomia amatoriale. Non si tratta soltanto di quelle che in inglese si chiamano “common misconceptions” o “astronomy myths”, vere e proprie credenze fasulle che si tramandano da generazioni nel nostro (piccolo) mondo di osservatori del cielo; circolano … Continue reading