hellocetus is an astronomy calendar for planning supermoons, following Moon phases, checking local Sun and Moon times, and comparing planet positions. Browse long-range events or open today’s sky data in one focused app.
Plan ahead with the supermoon calendar
• Browse long-range supermoon dates and astronomy events by year
• See exact local event times and countdowns for upcoming supermoons
• Explore Supermoons, Micromoons, Blue Moons, Black Moons, Harvest Moons, Hunter’s Moons, Blood Moons, Super New Moons, and Micro New Moons
• Find solar and lunar eclipse dates in the same event calendar
Follow the Moon day by day
• View a monthly calendar with each day’s Moon phase and illumination
• Open full moon details with the local event time, moonrise, moonset, city, time zone, and sky position
• Check today’s moonrise, moonset, phase, illumination, and lunar angle
• Save observation notes, plans, and reminders directly on calendar dates
• Receive optional alerts one hour before supported astronomy events
Compare planets and the sky
• Switch between Local Sky, Earth-centered, and Sun-centered planet views
• Compare altitude, azimuth, brightness, longitude, latitude, distance, right ascension, declination, and elongation
• Follow short-term planetary motion with timeline views
• Use a selected city or saved GPS location for local calculations
• Compare standout constellations above the horizon across countries and representative cities
• Explore planet surface previews in a clean globe-style interface
Daily Sun and Moon information
Check sunrise, sunset, total daylight, day-length change, moonrise, moonset, phase, and illumination at a glance. hellocetus brings long-range planning and everyday sky data into one focused experience.
Free and Premium
hellocetus includes advertising. Optional monthly, yearly, or lifetime Premium removes ads and unlocks the Home Screen full moon widget. Current products, localized prices, renewal details, and purchase terms are shown in the app before purchase.
Available in 22 supported languages.
Terms of Service:
https://hellocetus.com/terms/
