Stars of the Night
Sidera Noctis is a resource for observational astronomy enthusiasts, students, and citizen scientists. The site supports the full workflow of an observing session — from weather assessment and target selection to field data collection and sky quality research — along with educational content on light pollution and practical strategies for finding productive observing sites.
The Weather page aggregates current conditions from NOAA observation stations, hourly meteograms, animated radar, GOES infrared satellite loops, sky cover forecasts, and ClearOutside and Clear Sky Chart astronomical seeing forecasts — all on a single dark-themed page with GPS-based location detection.
The What's Up? page calculates — entirely in the browser, with no external API calls — the current position of the Sun, Moon, and all seven planets, together with tonight's visible deep-sky objects filtered by altitude and the local astronomical dark window. Rise, transit, and set times, current altitude and azimuth, estimated sky brightness, and magnetic declination are all updated in real time using your device's GPS position.
The Observing Planner builds on the same astronomy engine to provide structured decision support: an Observing Quality Index (OQI) scoring sky darkness, transparency, seeing, and lunar interference; a ranked list of the best DSO targets for the night; aperture-specific guidance from naked eye through large observatory instruments; and a recommended step-by-step session sequence tailored to current conditions.
The Calendar page provides an annual rise and set chart for the Sun, planets (Mercury through Saturn), and selected deep-sky objects. Months run down the vertical axis and local time runs horizontally, centered on midnight — the same convention used in the Sky & Telescope Skygazer's Almanac. Rise times are shown as solid curves, set times as dotted curves, and each object can be toggled on or off independently. A today line with per-object time annotations makes it easy to see at a glance exactly when any object rises or sets on the current date.
The Light Pollution page covers the science and cultural impacts of artificial sky glow, addresses common misconceptions, and provides practical mitigation strategies — with the goal of helping observers understand and evaluate sky quality at any site.