Solar Eclipse Viewing Time Calculator

How to calculate Solar Eclipse times?

Eclipse times are computed using celestial mechanics, observer's precise location, and Earth's rotation variations (delta-T).

Formula: Using Besselian elements and local topocentric corrections: contact_times = f(date, lat, lon, elevation, deltaT)

Using the Solar Eclipse Viewing Time Calculator: an example

Example inputs: Date=2026-08-12, Lat=43.6, Lon=-116.2, UTC-7 (DST=no), elevation=200 m.

Step-by-step calculation:

1. Convert input date/time to Terrestrial Time (TT).
2. Apply Besselian elements to determine eclipse geometry.
3. Compute local topocentric contact times for your exact location.
4. Convert calculated times from TT to your local time zone.

This calculator helps planners and photographers know exact local eclipse times for optimal viewing.

Frequently Asked Questions

How accurate are times in Quick vs Precise mode?

Quick mode offers good estimates, while Precise mode uses more complex calculations for higher accuracy, crucial for photography.

Do I need to adjust for Daylight Saving Time?

Yes, the calculator provides UTC times; you must manually adjust for your local time zone and any DST in effect.

What is delta-T and why does it matter?

Delta-T is the difference between Terrestrial Time and Universal Time. It accounts for Earth's irregular rotation, vital for precise timings.