Night Sky

A calendar that says “full moon on the 12th” leaves out the part you need: whether it will be up over your street, at what hour, and how high. Night Sky gathers the free tools that answer for your own city and its clock, tonight, this month and this year. There is nothing to sign up for, and the city you type is forgotten once the answer is out.

Tonight: the Moon, the twilight and the color of the sky

Give the moon phase calendar your city and a moment, and it returns the state of the Moon exactly then, with a card to share. What colour is the sky names the light over that city (golden hour, blue hour, nautical twilight or night) and when it changes next. The golden hour calculator gives sunset, civil dusk, moonrise and moonset for every day of the month.

This month: the dark nights sit around the new moon

Asked for the month, the moon calendar gives one row per night: illumination, moonrise and moonset, and the height that tells you whether it clears the buildings. Illumination is the figure to read, since 30% and 70% make very different nights. The Milky Way nights calendar keeps the nights of the next twelve months when the galactic core is up, the sky astronomically dark and the Moon out of the way. I would choose nights by the Moon first and check the forecast last: the Moon is known a year ahead, the clouds two days out.

This year: the seasons, your city’s Manhattanhenge, the retrograde periods

Equinox and solstice dates gives the year’s four instants to the minute in UTC, then on your city’s clock, with its earliest sunset and latest sunrise, which do not fall on the solstice. Every city has its Manhattanhenge, and nobody publishes the date: name where you stand and the landmark at the end of the street, and the Sun and Moon alignment planner returns the days of the next twelve months when the Sun or the Moon crosses that line, low in the sky. The planet retrograde calendar lists every retrograde period of a year, Mercury through Pluto, station to station.

The retrograde dates can land in your own calendar

Subscribe to the retrograde calendar and each period arrives as an event in the calendar you already look at; the table also downloads as a file. Cards to share come with a Moon moment, a Milky Way run and an alignment pass; the sky color tool offers a snippet for your own page that redraws itself every ten minutes. None of these tools sees clouds or light pollution, and the moon calendar does not predict eclipses.

Questions

Is there a free stargazing app online?

Night Sky runs in the browser, free and without a limit. The tools that take a city answer in its local time; equinoxes and retrograde stations come in UTC, the one form true everywhere.

Is Mercury retrograde right now?

Ask the retrograde calendar for this year and read the Mercury rows: if today falls between a station retrograde and the station direct after it, it is. That happens three or four times a year, for about three weeks each time.

Where do I find my latitude and longitude?

Type your town into the latitude and longitude finder, which returns the coordinates in decimal, DMS and DDM with the time zone. The sky tools here need only the city, picked from their list.