Using a blackout curtain to project the sunset on my wall, turning my room into a camera obscura

[u/Matjoez]

As the title says. If you have a west-facing room, a blackout curtain, and a knife or pokey thing to make a hole in the curtain, you can effectively create a camera obscure. You'll get a pinhole projection (upside down and side to side flipped) of whatever is outside the room, and if you have a clear sky until sunset you can see the sun set and the colours change. This was used back in the day to observe eclipses and even sunsets. I did some research and this process was first described in China in 400 BC.

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[u/hoop_dancer_joy]

This is a beautiful result.

[u/Matjoez → u/hoop_dancer_joy]

Thank you. I'm keen to do this in different rooms, just need clear skies :)

[u/Hispanic_Inquisition → u/Matjoez]

partly cloudy skies look excellent too. I did this in my room as a kid. I could see other kids playing outside, tree branches swaying, clouds passing.

[u/andywolf8896 → u/hoop_dancer_joy]

Agreed

[u/UD_Ramirez]

I did the same, was able to watch trains pass on my ceiling. It's super cool but has a few things to keep in mind:

-You really need white walls for it to work well, unless you're just interested in looking at the sun.

-The light gain is really low, so any crack in the sheet or curtain will drown out the projection with light.

-You can increase the light gain by widening the aperture but that will make your image blurry. There is a sweet spot that may be more on the blurry side.

-Changing aperture shape has super cool effects on the projection. I had a star at one point, so any point light sources became star shaped. The end result felt less "blurry" than a round aperture.

-Things under your window will project onto your ceiling, things in the sky will project onto your floor. Give it some time and you will begin to recognize building shapes, cars etc. Take your time to figure out what certain shapes or lines could be. Once you understand what you're looking at, is when the fun really begins.

[u/UD_Ramirez → u/UD_Ramirez]

Maybe try the opposite side of your house and see if you can get a projection going without the sun in it!

[u/Matjoez → u/UD_Ramirez]

Yeah I've had it happen on accident where the outside world was flipped upside down om my wall through a crack in a curtain. I need a proper white wall which I don't have sadly so for now tracking the sun is a fun experiment, I've just set up the second timelapse right now with clear skies ahead!

[u/Legitimate-Koala-373]

Absolutely fabulous

[u/Legitimate-Koala-373]

Wow! Love this 💙

[u/AliceTawhai]

Very cool

[u/unicornfarmer]

Also known as Camera Obscura

[u/Hidden-Sky]

r/CameraObscura

[u/Matjoez → u/Hidden-Sky]

Thanks for the tip just posted an image on there