MessierMate vs Orbiting Sky

110 deep-sky objects. See which ones are above your horizon right now, sorted by urgency so you never miss one before it sets. MessierMate is the complete companion for deep-sky observing, and it's completely free. No ads. No in-app purchases. Ever. Whether you're under the stars for the first time or chasing the Messier Marathon, the app tells you exactly what's visible from your location right now, helps you plan future nights, and keeps a log of every session. TONIGHT Open the app and instantly see which of the 110 Messier objects are above your horizon, sorted by urgency so you never miss a galaxy that's about to set. Each card shows altitude, compass direction, time until it sets, and an altitude arc so you know exactly when to look. Filter by object type (galaxies, nebulae, star clusters) and minimum altitude, and switch between three card layouts to match your observing style. PLAN Tap any night on the monthly calendar and see dusk time, moon phase, moonrise, and a count of how many objects are visible. Browse your targets in a list or on a timeline that shows when each object rises, peaks, and sets. Star objects to build a target list for the night. The app automatically detects Messier Marathon nights and flags them on the calendar. LOG Record every session with the date, location, duration, and which objects you observed. Add notes and photos to individual objects. Share a session with a friend via a short share code. No account needed on their end to view it. YOUR SKY, YOUR PRIVACY Your GPS coordinates never leave your device. Only your site name and Bortle class are synced to the cloud, never your exact coordinates. There are no ads and no analytics trackers. Guest mode is fully functional: the app works completely offline without an account. BUILT FOR DARK SITES A dark theme and a Red Night mode protect your night vision. The interface is designed to be usable by feel, with minimal taps needed to log an observation while you're at the eyepiece. WHAT'S INSIDE - All 110 Messier objects with real-time altitude and azimuth calculations - Tonight view ranked by urgency, objects setting soonest appear first - Monthly planning calendar with moon phase and object counts - Rising, peaking, and setting timeline for any night - Automatic Messier Marathon opportunity detection - Session log with notes, photos, and shareable codes - Equipment manager for telescopes, eyepieces, filters, and cameras - Bortle scale support for accurate sky darkness settings - Red Night mode for dark site use - Works offline, no internet connection required for sky calculations - Free, with no ads and no in-app purchases Whether you're hunting your first galaxy or completing the catalog for the tenth time, MessierMate keeps you focused on what matters: the sky.

A new window onto Sky & Earth. • See the sky above an interactive map, with full-screen Sun, Moon and horizon observations. • Designed for iPhone Duo: fold along the horizontal hinge to place the sky upright and the map on your desk. See the sky’s rhythm on the map. Orbiting Sky turns any place and time into a clear, interactive view of daylight, moonlight, shadows, twilight, and eclipses. Move across the map, travel through time, and watch the geometry of the Sun and Moon change instantly. EXPLORE DAYLIGHT • See the moving day-and-night boundary • Distinguish civil, nautical, and astronomical twilight • Follow the subsolar point around Earth • Show sunlight and moonlight direction vectors UNDERSTAND YOUR SKY • View Sun and Moon elevation and true-north azimuth • Trace projected daily arcs above the local horizon • Estimate the direction and length of a vertical object’s shadow • Inspect lunar phase and illumination DISCOVER ECLIPSES • Browse solar and lunar eclipses visible from the selected location • Filter partial, annular, total, penumbral, and lunar events • Jump directly to each event’s local maximum • Visualize eclipse shadows on the world map CONTROL TIME • Choose any date and time • Play time forward or backward at multiple speeds • Use the selected location’s civil time zone • Search all IANA time zones or switch to UTC Orbiting Sky works on iPhone, iPad, and Mac, supports eight languages, and requires no account. Optional rewarded ads unlock 30 minutes of Pro access; a Pro purchase removes ads. Astronomical and shadow results are educational estimates. Do not use Orbiting Sky for navigation, eye-safety decisions, or professional eclipse-contact timing.