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Instruments · 10 free tools

Free astronomy tools

Tools for stargazers, astronomy societies, schools and Scout groups across the UK. They are free, there is nothing to join, and you are welcome to link to them.

  1. Tonight's sky over your town When it gets dark, which planets are up and where to look, and what the Moon is doing, for any UK town and any night.
  2. Moon phase today and the next full Moon Tonight's Moon, how much of it is lit, and when the next full and new Moons arrive in London time.
  3. UK sky events countdown Days, hours and minutes to the next meteor shower peak, full Moon, eclipse and change of season, worked out for the UK.
  4. Printable star chart for the UK The whole sky over the UK for any month and hour, with the constellations and the brightest stars named.
  5. Sunrise and sunset times Today's sunrise, sunset and day length for any UK town, with a table for a month or a whole year that you can print.
  6. Messier catalogue checklist All 110 Messier objects, with the months they are best on a UK evening and how high each one gets.
  7. Telescope magnification calculator Type in your telescope and eyepiece to see the magnification, how much sky fits in the view, and the most and least power that telescope can really use.
  8. Light-year converter Light-years to kilometres, miles and au, and how long light takes to reach us from the Moon, the Sun, the planets and the stars.
  9. Solar system scale model and planet walk Choose a size for the Sun or a length for your walk, and see how big each planet is and how far away to put it, using NASA figures.
  10. Julian date converter Today's Julian Date, ticking live, with conversions from any date and time to JD and MJD and back.
A small white dome observatory in a frosty back garden at night, its slit open to a starry sky, a bare tree beside it.

For astronomy societies, schools and groups

Every tool here is free to use and free to link to. If you run an astronomy society, a school science club or a Scout or Guide group, put a link on your website or in your newsletter. Most answers can be shared as a link: set the tool up, then copy the address.

Three of them can sit on your own website too: tonight’s sky, the sky events countdown and the light-year converter. The code to copy is at the bottom of each one.

When you want the sky on the wall

The same sums drive our two made-for-you prints: the personalised star map, the sky over a place at a minute you choose, and the Moon phase print, the Moon on any date from 1900 to 2100. Both come with a free preview.