SOLAR EPHEMERIS & SUB-EXPOSURE CALCULATOR

Tonight’s Chronological Schedule.

From Civil Dusk (-6°) to Astronomical Darkness (-18°). Plan target transit timings, lunar separation windows, and compute mathematical sub-exposure exposure times.

Solar Ephemeris & Dark Window

Local Solar Noon 13:08 · True Solar Midnight 01:08

ASTRONOMICAL DARK STARTS 21:18 LOCAL

Sunset19:42Sun at 0° Horizon

Civil Dusk20:12Sun at -6°

Nautical Dusk20:46Sun at -12°

Astro Dark (Start)21:18Sun < -18° · 100% Dark

Astro Dawn (End)04:006h 42m Total Dark Window

Optimal Sub-Exposure Duration Calculator

NOISE SWAMPING ENGINE

Prevents both under-exposure (dominated by camera read noise) and over-exposure (bloating star cores and wasting dynamic range).

Telescope Focal Ratio: f/4.8

Sky Darkness: Bortle 4

Camera Read Noise: 1.6 e⁻

Filter Bandpass

RECOMMENDED SINGLE SUB-EXPOSURE

900 SECONDS (15.0 mins)

Swamps camera read noise by 10x with zero core saturation risk.

Gain: Unity (100)

Offset: 30 ADU

Prime Targets Transit Timings

CULMINATION

M31 Andromeda Galaxy

Window: 22:30 – 03:45

Transit: 01:24 AM

Peak Alt: 78°

M42 Orion Nebula

Window: 01:15 – 05:00

Transit: 03:15 AM

Peak Alt: 54°

M51 Whirlpool Galaxy

Window: 21:40 – 02:10

Transit: 23:45 PM

Peak Alt: 82°

M101 Pinwheel Galaxy

Window: 23:00 – 04:30

Transit: 02:10 AM

Peak Alt: 74°

OPEN SCRUBBABLE INTERACTIVE CELESTIAL TIMELINE ▹