Astronomical suite
Horizon 87
Horizon 87 is a browser astronomical suite built by Naresh Prasanna. It runs at horizon87.com with no install — open the tab and explore.
What it does
- Orrery — geocentric and heliocentric views of the solar system, driven by JPL ephemeris (DE442s when cached) with VSOP87 as a fast fallback.
- Sky dome — local star map from your date, time, and observer site; object visibility checks for planets and deep-sky targets.
- Event scans — planet parades, tight alignments, and solar/lunar eclipses over a chosen year range.
- Mission lab — preliminary Earth–Mars porkchop plots for comparing launch windows (screening grade, not flight-ready).
Who built it
Naresh Prasanna, a high school student, started with a simple question — when do planets line up? — and ended up wiring in NASA/JPL data, eclipse geometry, and transfer-orbit math. Scientific mentor: Dr. Chrisphin Karthick (Indian Institute of Astrophysics).
Honest limits
Horizon 87 is for learning and exploratory screening, not publication astrometry or mission operations. Refraction uses standard formulas, not live weather. Transfer plots use patched-conic Lambert screening, not GMAT-level optimization.
More detail
Launch the app · Technical build notes (ephemeris math, validation, file map)