New York, USA
Lat: 40.71°•Lon: -74.01°
ASTRONOMICAL DARK SKY
10:41 AM
True darkness begins; sky is free of atmospheric solar skyglow
First Light (Civil Dawn)11:49 AM
Sunrise12:20 PM
Solar Noon04:59 PM
Sunset09:38 PM
Last Light (Civil Dusk)10:09 PM
True Night (Astro Dusk)11:17 PM
Astronomical Dawn Calculator (End of True Night)
Sun Hits -18° Below Horizon•Conclusion of True Night•Deep Sky Astrophotography Cutoff•Live Countdown to Twilight
Identify the Exact End of Pristine Astronomical Darkness
Astronomical dawn marks the moment the sun ascends to 18 degrees below the horizon in the morning. Before this instant, the sky is completely black and free from all solar skyglow. Once astronomical dawn strikes, subtle Rayleigh scattering begins in the high atmosphere, ending the window for faint deep space astrophotography.
Essential for telescope observers, astrophotographers, and dark sky enthusiasts seeking to maximize unpolluted imaging hours.
How to Use the Astronomical Dawn Calculator
1
Select your observatory, dark sky campsite, or home city.
2
Check the exact minute the sun crosses -18° below the horizon.
3
Conclude long exposure nebula and galaxy imaging before morning skyglow begins.
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Frequently Asked Questions
What is astronomical dawn?
Astronomical dawn is the moment the geometric center of the sun is 18 degrees below the horizon in the morning, marking the transition from true night to astronomical twilight.
Can the human eye see light at astronomical dawn?
To the naked casual observer, the sky still appears dark, but sensitive astronomical instruments and photometers can detect early atmospheric light scattering.
Why is astronomical dawn important for astronomers?
It marks the absolute end of the observation window for faint deep-sky objects like distant nebulae, galaxies, and star clusters.
Ready to Use the Astronomical Dawn Calculator?
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