Tutorial

Adding a planet to your photos

On the walk we tell you to put the phone away and just be there. Which is good advice and slightly inconvenient, because the best shot of the day is usually the one somebody else took, on a real camera, while you were busy holding a card.

So there's the photo editor. Drop in a photo taken on anything — a DSLR, a friend's phone, a film scan — show it where your card was, and it places the planet at true scale, exactly the size you were standing next to.

When you'd use it

• The good camera. Someone brought a proper camera, or you want the shot framed by a person who isn't also operating the AR. Shoot normally, composite later.
• The big planets. Jupiter and the Sun are large enough that getting them, the card and a person into one live AR frame is genuinely awkward. On a photo you have all the time in the world.
• The AR wouldn't cooperate. Bad light, a borrowed phone, a dead battery, a browser that wouldn't give up the camera. Take an ordinary photo with the card in shot and do this bit on the train home — you get exactly the same true scale.
• You're on a laptop. Live AR needs a phone; the editor doesn't. It's arguably nicer on a big screen.

Taking the photo

Shoot however you like. The one thing to remember: keep the card in frame — the Sun card, or the back of the postcard — reasonably large and in focus.

What makes a photo easy to work with:

• All four corners of the card visible. That's what the size is measured from. A card half out of frame or hidden behind a thumb can't be outlined.
• The card a decent size in the picture. A card that's forty pixels across can be outlined, but small placement errors turn into large size errors.
• Flat and steady. Propped on a bench, held against a wall, laid on a wall top. A curled or bent card skews the geometry.
• Somewhere with depth behind it. The planet lands where the card is, so leave space around it for something the size of Jupiter.

Shooting on the phone you'll edit on is convenient for one reason: the photo carries the location it was taken at, and the editor uses that to work out which walk and which planet you mean, so it asks you nothing. Photos from a separate camera usually don't, and you'll pick from two dropdowns instead. That's the whole difference.

Three steps in the editor

1 · Drop the photo in

Go to solarsystem.city/editor, then drag a photo onto the page or tap Choose a photo. JPEG, HEIC, PNG and WebP all work, straight off the camera — no need to convert anything.

2 · Outline your card

Tell it which piece is in the photo — the wallet card or the postcard back — then tap the card's four corners in the picture.

That's the whole placement mechanic. Four corners of a rectangle whose real proportions we know is enough to work out exactly how the card was sitting in space, which is why this never fails, never needs a good camera, and works the same on every device.

Tap accuracy is the accuracy of the result, so it's built as an editor, not four taps:

• Press and hold a corner to open a magnifier showing the original photo at full detail.
• Drag to adjust. Corners keep moving after you've placed them, and the drag is geared down — your finger steers, the corner aims.
• Arrow keys nudge the selected corner one pixel at a time.
• Start again clears the outline if it's gone wrong.

Take your time here. Every degree of sloppiness in the outline is a degree of wrongness in the planet's size and angle — and getting it right is the difference between a composite and a photograph.

3 · The planet lands

Hit the button and it's there, at true scale, sized from the real card in your photo.

If the photo knew where it was taken, the editor has already worked out the walk and the planet and says so in one line. If it didn't, or if two stops were too close to call, the pickers open by themselves — choose the walk and the planet, and it re-renders instantly. Being wrong here is cheap: it only changes the planet's size, and everything stays editable.

Making it look right

The planet's position and size are fixed by the card — those are the honest part and you can't move them. Everything about how it's lit and which face it shows is yours:

• Drag the planet to spin it. Turn Jupiter's Great Red Spot toward the camera, put Saturn's rings at an angle you like, find the continent you want on Earth.
• The sun slider moves where the light comes from. This is the one that matters most: a planet lit from the opposite side to everything else in the photo reads as fake however correct its scale is. Match the shadows in your picture.
• Zoom to planet checks the detail close up.
• Adjust outline goes back if the placement needs another pass.
• The reset button puts the framing back to where it started.

Then Download. The finished image saves to your device and it's yours — post it, print it, do what you like with it.

These are the same controls as the live AR view, on purpose: same drag to spin, same sun behaviour. There's only one thing to learn.

If something's off

The planet looks too big or too small.

Almost always the wrong piece is selected — a postcard back is more than twice the width of a wallet card, so picking the wrong one scales everything with it. Check that first, then check the outline is on the card's actual corners rather than just inside them.

It named the wrong walk or the wrong planet.

Open the pickers and change them. The guess comes from where the photo was taken, and stops on a small-Sun walk can sit close enough together to be ambiguous.

The planet is off the edge of the picture.

It's landing where the card was, at its real size — for an outer planet on a large-Sun walk that can be bigger than the frame. Try a photo where the card is smaller in shot, or further from the edge.

It won't read my photo.

Very large images are scaled down to work with, which is normal. If a file is refused outright it's an unsupported format — re-export as JPEG and it'll go in.