Find out what planets are visible tonight, the brightest planet in the sky right now, and the best times to observe with our interactive astronomical almanac.
Launch our Astronomical Almanac!
Find everything you need for observing tonight in one place. Our Astronomical Almanac presents basic astronomical data customized for your location for any date from AD 1600 to 2400. The interactive tool displays sunrise and sunset times, morning and evening twilight times, moonrise and moonset times, the Moon's phase, a list of naked-eye planets visible in the evening and morning skies, rise and set times for each of these planets, and more.
How to Use the Astronomical Almanac to Find What Planets Are Visible Tonight
When you launch the Astronomical Almanac , it will open in a new window. The almanac initializes itself to the current date and time based on your computer's clock and sets the latitude and longitude to that of Sky & Telescope's office in Cambridge, Massachusetts. You can reset the location by using the Country and City pull-down menus, or you can set latitude and longitude directly.
Once you've picked the city nearest your location, the almanac sets the corresponding time zone from your computer's clock and decides whether daylight-saving time (DST) is in effect. Clicking Reset restores the almanac to the current date and time. You may also step forward or backward in time by 1 hour, day, or week by clicking the appropriate buttons.
The first time you launch the almanac, set your location and time zone, then you'll have the option of loading these preferences next time you come back. You can save your location for future use using the "Save location?" link. If you have saved your location before, you'll need to load the new location using the "Load location?" link on the almanac page.
Once you've entered your date, time, and location, click Calculate and the almanac will show you the Julian Date (for "official" astronomical timekeeping), your location (latitude and longitude), the local date and time, and your time zone relative to Universal Time (which is basically the same as Greenwich Mean Time).
Below that, the tool displays a graphic representation of the Moon's phase and then reports the Moon's age (in days since the last new Moon). The Moon's displayed phase is accurate to within a fraction of a day. It is indicated using 28 different symbols, whereas a complete lunar cycle takes 29½ days. Why the discrepancy? Simply to ensure that on the dates of new, first-quarter, full, and last-quarter Moon, the correct symbol is always shown.
Next to the Moon you'll find the local sunrise and sunset times, moonrise and moonset times, and times when twilight ends (in the evening) and begins (in the morning). You'll also find listings of which naked-eye planets, if any, appear in the evening and morning skies, followed by a text box indicating any significant astronomical events that occur on the specified date, such as a meteor shower or a conjunction of the Moon and a bright planet or star.
Scroll down within the tool to view detailed information about the Sun, Moon, and five naked-eye planets.
Listed first are the coordinates of right ascension (R.A.) and declination (Dec.), which give the object's position on the celestial sphere for the equinox of date. Next are listed the apparent visual magnitude; angular size in arcseconds (arcminutes for the Sun and Moon); percentage of the disk illuminated by sunlight (phase); and, for the specified location, the local times of the object's rising, transiting (appearing highest in the sky), and setting.
For more on observing the planets you see tonight, visit our planet observing guides.