Sun, Moon & Earth Movement Simulator for St. Charles, MO
Where the sun and the moon are from St. Charles, MO, at any moment you choose. Today the sun rises at 6:10 AM and sets at 8:07 PM — 13 h 57 m of daylight — and the moon is a waning crescent, 18% lit. Drag the slider through a day, a week or a month and watch all of it move.
Showing St. Charles38.788°, -90.497°
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St. Charles is the marker on the globe — on the night half at the time shown, riding the dotted circle its spot traces as the Earth turns. The moon is 50° from the sun in the sky then, and that angle is the phase: waning crescent. You are looking down on the Earth from far above its orbit, from the north — the side you are on — with sunlight arriving from the top left, so the half of the Earth facing that way is the half having its day. Sizes and distances are not to scale; the directions are.
What St. Charles’s latitude does to the picture
At 38.8° north, St. Charles has a moderate swing through the year — 14 h 53 m of daylight at the longest day and 9 h 27 m at the shortest — and the sun never quite reaches straight overhead.
Baked for the moment this page was built; the simulator above recomputes everything in your browser for whatever instant you set.
This picture is not to scale — here is how far out it is
Every direction and angle in the simulator is real. Every size and distance is not, and it is worth being exact about which, because a diagram that quietly lies about the solar system is how people end up thinking the moon is a few Earth-widths away.
Try it in a corridor. Shrink the Earth to a 16 mm marble. The moon is then a 4.4 mm bead — about a peppercorn — held 48 cm away. The sun is a 1.7 metre ball, taller than a person, standing 188 metres down the road: nearly two football pitches. Nothing about that fits on a screen, so this picture keeps the angles honest and lets the distances go.
Those figures are for the picture as it sits on this page. The drawing's HEIGHT is what sets every size in it, so a wider frame changes nothing except the gap between the sun and the Earth — which is why full screen is less wrong than this: it hands the picture the screen's own shape, and on a phone held sideways that puts the sun roughly 1,575× too close instead of 3,151×. Still hopeless, and better.
What you can trust here: the direction of the sun and the moon from the Earth and from your own spot; which half of the Earth is in daylight; the angle between the moon and the sun, which is the phase; the tilt of the Earth’s axis and how much of your daily circle falls in the light. What you cannot: any distance, the sun’s size, or anything about eclipses.
What the picture is quietly telling you
Tidal locking and why “the dark side of the moon” is a misnomer; why moonrise slips later every day; the two different lengths of a month; why everyone sees the same phase the right way up for them; why there is not an eclipse every month; and how the moon–sun angle sets the tides. All of it is written up once, on the simulator’s own page, along with how to use this in a classroom — nine activities, each naming a control on this page and a row in its read-out.
St. Charles on the rest of the site
Nearby, for a side-by-side: St. Peters, MO (7 mi) · Florissant, MO (9 mi) · Chesterfield, MO (10 mi) · O'Fallon, MO (11 mi) · St. Louis, MO (20 mi) · Belleville, IL (33 mi).
The whole solar system
This page is the Earth's own neighbourhood. If the question is where the planets are — Mercury and Venus racing round inside us, Jupiter and Saturn crawling, Neptune barely moving in a lifetime — that is the solar system simulator, with the same kind of slider over a month, a year, a decade or a century, and a zoom that climbs from the Earth and Moon out to Neptune.
Make a link to a particular sky
Pick a place, a starting date and time and how much time the slider should cover. The link builds itself as you choose, and the sentence under it says in words where that link goes — so you can check it before you send it.
What the parameters mean
citya city slug — ?city=seattlelat & lonany coordinates — ?lat=47.6&lon=-122.33, with optional name and tzdateYYYY-MM-DD, the day the span startstimeHH:MM in the place’s own clockspanday, week or monthCity slugs are the ones in the address of a city page: /sun/seattle/. Coordinates win if you give both.
St. Charles, MO: common questions
What time does the moon rise in St. Charles, MO tonight? Tonight the moon rises at 1:08 AM and sets at 5:08 PM in St. Charles, MO, and it is a waning crescent, 18% lit. Tomorrow it rises at 2:10 AM — 63 minutes later, because while the Earth turns once the moon has moved on about 13° round its orbit and this spot has to turn that bit further to catch it. These are today's figures; the simulator recalculates them in your browser for any date.
Why is the moon that shape from St. Charles, MO tonight? Because the moon is 50° away from the sun in the sky right now, and that angle IS the phase — nothing is covering the moon up. At 0° it sits in the same direction as the sun and we see its unlit side (new moon); at 180° it is opposite the sun and fully lit. 50° gives a waning crescent, 18% lit. Everyone on Earth sees the same phase at the same instant; what changes with where you stand is which way up it looks, and the disc on this page is drawn the right way up for the northern hemisphere.
What time is sunrise and sunset in St. Charles, MO today? The sun rises at 6:10 AM and sets at 8:07 PM, giving 13 h 57 m of daylight. At 38.8° north the longest day of the year runs to 14 h 53 m and the shortest to 9 h 27 m. Set the slider to a day and press Play to watch the marker ride in and out of the lit half.
Is this drawing to scale? No, and it cannot be. The moon is drawn about 24 times too close to the Earth, and the sun about 3,151 times too close and 52 times too small. What IS true is every direction and angle: where the sun and moon lie around the Earth, which half of the Earth is lit, and where St. Charles, MO is on it.
How the positions are worked out, and where they stop being reliable: sunrise & sunset, moon phase.