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Calculate fishing line strength and leader size for target species, technique, and drag setting based on line type and test rating.
Estimate fish weight from length and girth measurements using species-specific formulas when you do not have a scale on the water.
Calculate optimal trolling speed in mph and knots for target fish species, lure type, and desired lure running depth on lakes or oceans.
Satellite orbits are propagated from NORAD TLE data using SGP4/SDP4 models. Position is computed in Earth-centered coordinates and converted to azimuth and elevation for the observer.
A pass is visible when the satellite is above the horizon (elevation > 0°), sunlit (not in Earth's shadow), and the observer is in twilight or darkness (Sun below −6°).
Max elevation determines pass quality. Passes above 40° are excellent; 20–40° good; below 10° often hidden by trees and buildings. Magnitude brighter than 0 is easily visible.
Updated: July 2026
ISS rises SW at 8:42 PM, reaches 65° elevation at 8:45 PM (magnitude −3.2), sets NE at 8:48 PM. Three-minute pass — excellent naked-eye viewing.
Bright satellite flares from antenna reflections peaked at magnitude −8. Iridium constellation deorbited, but ISS and Starlink trains still produce bright predictable passes.
Pass at 45° elevation with 3-minute duration. Use Heavens-Above or this calculator for exact azimuth at max elevation to pre-aim camera for transit composite.
ISS is only visible during twilight when it is sunlit but the ground is dark. Midnight passes are invisible because the station is in Earth's shadow.
Satellite orbits decay and shift. TLE data older than a few days can shift pass times by minutes. Refresh TLE data within 72 hours for accurate predictions.
The International Space Station and other bright satellites are visible to the naked eye during evening and morning twilight when the sky is dark but sunlight still illuminates the spacecraft. This calculator predicts pass times, max elevation, direction, and duration from your location.