About
Nightglass answers one question: is tonight worth going outside for, and what should you look at first? It is not a star map. Half a dozen good apps already show you what you are pointing at, and that is the easy half. Nightglass does the part they leave to you. It works out which objects actually clear your horizon while the sky is properly dark, how high each one climbs, how long the window lasts, and whether the Moon is going to ruin it, then ranks them for the night you pick. The Moon handling is the piece that matters most and the piece almost every other app reduces to a phase icon. A full Moon does not spoil everything equally: one low in the west costs you nothing in the east, it barely touches the planets, and it destroys a faint galaxy. Nightglass works that out per object and per moment, and tells you to wait for moonset rather than pretending the night is lost. Everything is computed on the device from orbital mechanics, checked against the standard published algorithms, so it works in a field with no signal, which is where you will actually be standing. There is no account, no sign in, no server and no network request of any kind. The whole app is dark with an amber accent, because blue and white light destroy the dark adaptation your eyes take twenty minutes to build, which is the same reason observers use red torches.
Features
- A ranked plan for tonight, from where you are standing
- The window each object is worth observing in, and when it is highest
- Real astronomical darkness, and it says so when midsummer never gets there
- Moon interference worked out per object, not a single phase icon
- An altitude curve for every object, so you can see what rides high
- The Moon, all seven planets, 18 bright stars and the 110 Messier objects
- Works entirely offline, with no account, no adverts and no tracking