A browser-based astronomy planning tool that shows altitude graphs for celestial objects. Helps you figure out when and how long a target is visible from your location.
- SIMBAD lookup - Type any identifier (M31, NGC 7000, Vega, etc.) and it validates against the SIMBAD database in real-time
- Altitude graph - 24-hour altitude curve with twilight shading (civil, nautical, astronomical)
- Custom horizon profile - Upload a horizon file (NINA/Stellarium format) to see where your local horizon blocks the view
- Moon overlay - Optional moon altitude curve to plan around moonlight
- Key stats - Visible time in astronomical night, above-horizon time at night, min/max altitude
- Transit & rise/set - Transit direction, altitude, and time; rise and set times
- North crossings - Marks where the object crosses due North, above or below Polaris
- "Now" indicator - Yellow vertical line showing current time on the graph
- Geolocation - Auto-detects observer location, with manual override; persists across sessions
- Object history - Remembers your last 5 searched objects
npm install
npm run devOpen http://localhost:5173 in your browser.
Plain text, one point per line: azimuth altitude (degrees), space or tab separated. Lines starting with # are comments.
0 10
45 15
90 20
135 12
180 8
225 10
270 15
315 12
360 10
Compatible with NINA and Stellarium horizon exports.
npm run buildStatic files are output to dist/, ready for GitHub Pages or any static host.
- Vite
- Chart.js
- SIMBAD TAP API
- Vanilla JS with no framework