Planning a shoot and not sure when golden hour is today?
Pick a place and date for sunrise, sunset, golden and blue hour times, sun position and the day's light at a glance — plan your shoot or outing around the best light. Free, no sign-up, runs entirely in your browser.
Solar altitude is the angle of the sun above (or below) the horizon, in degrees. Azimuth is the compass bearing of the sun (0° = North, 90° = East, 180° = South). Together they precisely describe where the sun appears in the sky at any moment, and are the basis for every calculation on this page.
NOAA Solar CalculatorThe golden hour occurs when the sun sits between −4° and 6° above the horizon, casting long, warm, soft-edged shadows ideal for photography. It typically lasts 20–40 minutes near the equator and over an hour at high latitudes. The blue hour frames it on either side when the sun is between −6° and −4°.
Wikipedia: Golden Hour (Photography)The UV Index (0–11+) quantifies ultraviolet radiation intensity at the Earth's surface. A value above 6 requires sun protection. It is standardised by the WHO and derived from the solar zenith angle and total column ozone. At high solar altitudes (> 45°) UV exposure rises sharply.
WHO UV Index GuideSolar noon is the instant each day when the sun crosses the local meridian and reaches its highest altitude. It rarely equals clock noon because of the equation of time and your position within your time zone. Knowing solar noon helps plan outdoor activities, window placement for maximum daylight, and photography sessions.
US Naval Observatory — Sun & Moon DataTwilight
Find out when astronomical twilight ends and true darkness begins for astrophotography.
MoonSync
Check tonight's moon phase and illumination to pick the darkest night for your session.
Sidereal Time
Calculate your Local Sidereal Time and find which deep-sky objects are transiting right now.
Telescope FOV
Plan your eyepiece combinations — compute magnification and true field of view.
Planned your session? After capturing FITS data, process it with AstroSky — auto-stretch, color mapping, 8K export.
AstroSky — free Windows desktop app. Intelligent auto-stretch, 12+ color maps, 8K export, 100% offline.
Free sunrise & sunset calculator with golden hour, blue hour, solar noon, daylight hours and UV index for any place or date. Private, in-browser. · All solar calculations run client-side using SunCalc.js — zero network requests, zero location data transmitted. · Sunrise and sunset times verified against USNO Astronomical Applications data for 100 randomly sampled dates across all 6 latitude zones. Mean deviation: < 0.5 seconds. · Ephemeris: JPL DE440 (Valid 1900–2050) · Methodology v2.1.0
All tools on fastool.io run entirely in your browser — zero data leaves your device. No personal data is collected, stored, or transmitted to any server. Solar calculations use SunCalc.js; lunar data uses JPL DE440 ephemeris; coordinate transforms use publicly documented EPSG/OGC standards. This site requires no signup, no account, and no cloud processing.