CelestialGuide vs Cosmic Alerts

Celestial Guide is an interactive database of information about stars and planets. Its basic interface is a map of the sky as seen from any point on Earth at any point in time. The user can manually choose the time and location, or the iPhone's or iPad's GPS and clock can be used to select the current time and location. If the device is pointed at the sky, the map on the screen will be presented corresponding to the actual view in that direction. The star database includes stars brighter than magnitude 9. The user can select the minimum visible magnitude, which allows the map to conform to the stars which are visible to the user based on local viewing conditions. CelestialGuide presents accurate locations of planets and comets, including rendering of eclipses, transits and occultations that are visible from the selected location. CelestialGuide also has a database of Messier Objects. CelestialGuide also includes a Virtual Orrery, displaying the relative position of the planets and comets at any point in time.

Where in the sky, and how far from Earth, did it happen? This app plots gravitational waves, gamma-ray bursts, high-energy neutrinos and fast radio bursts using the observational data that research institutions publish. ■ A 3D map that uses real distances Earth sits at the origin. Events with a measured redshift are placed at their actual comoving distance. Turn the dial and the viewpoint travels from just outside Earth all the way to the edge of the observable universe — from looking up at the sky like a planetarium to seeing the whole universe at once, without a break. ■ All-sky map The whole sky on one page, in galactic coordinates with the Hammer-Aitoff equal-area projection. It is the same layout as the famous all-sky figure CGRO/BATSE produced from 2,704 gamma-ray bursts, so you can read off the fact those bursts scatter isotropically instead of crowding the galactic plane. ■ Colour is photon energy Twelve decades of energy, from µeV radio waves to PeV neutrinos, mapped to colour. Marker size is fluence — the total energy that reached us. Drag across the legend to show only the band you care about. ■ When something is unknown, it says so Most gamma-ray bursts have no measured distance. Empirical spectral relations can give an estimate, but the same observables map to several redshifts, so the value is not determined. This app never presents an estimate as a distance. Bursts with only a known direction are drawn as rays from the origin — so the fact that most bursts have no known distance is itself visible on screen. ■ Alerts for new events When a new event is published, the app creates a notification on your device. You can choose which event types to be told about. No push notification server is involved. ■ Data sources • GWOSC (Gravitational Wave Open Science Center, LIGO/Virgo/KAGRA) • GraceDB (LIGO/Virgo/KAGRA low-latency alerts) • NASA HEASARC (Fermi GBM / Swift BAT / CGRO BATSE burst catalogs) • NASA GCN (AMON/IceCube high-energy neutrinos) • CHIME/FRB Catalog 1 (CHIME/FRB Collaboration et al. 2021, ApJS 257, 59, CC BY 4.0) • Star background: Yale Bright Star Catalog All of it comes from archives those institutions publish openly. This app is unofficial and is not endorsed by or affiliated with any of them. ■ Also • English / 日本語 / Français / Deutsch / Español / 简体中文 / 繁體中文 • No account required • Retrieved data is stored on your device, so the last state is readable offline • Distances and lookback times use the Planck 2018 ΛCDM model