Exposure Calculator

Exposure Calculator

Plan sub-exposure length and total integration time. Estimate signal-to-noise ratio for your telescope, camera, target and sky conditions before you image.

Step 1 of 5: Pick a target to begin

Exposure Calculator

mm

mm

×

μm

mag/arcsec²

e⁻

e⁻/s

Recommended sub-exposure

600s

Sky-limited (10× read noise²)

SNR after 8h

2.2

48 × 600s subs

SNR vs total integration

Optimal (600s) 300s subs
0.320.640.961.281.61.922.242.562.883.23.523.844.164.484.85.125.445.766.086.46.727.047.367.688hours00.551.11.652.2

SNR 20 not reachable within 20h at these settings.

Sky background rate0.00 e⁻/s/pixel
Object signal rate0.002 e⁻/s/pixel
Sky per sub1 e⁻
Read noise²2.25 e⁻²
Sky / read-noise² ratio
0×

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