Roshni · Calculators · Sharp-star shutter
Sharp-star shutter
Start here, then inspect a test frame at your intended output size — the rule assumes a strict pixel-level standard.
Formula: t = (35·N + 30·P) / (F·cos δ), scaled by output tolerance K. N = f-number, P = pixel pitch in µm, F = focal length in mm, δ = declination.
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