Intro: Quick and Dirty Camera Obscura to View the Venus Transit or Solar Eclipses
I'll admidt that I was caught off guard by this Venus Transit that is coming up...in less than 24 hours of this writing. If you are like me then you have nothing ready to see this historic event. I also don't feel like keeping healthy enough to see the next one in over 100 years.
So, this is a quick and dirty Instructable for a quick and dirty Camera Obscura that you can use to view the transit with materials you likely have on hand. Procrastinators unite...later!
For this you will need:
- Two 3x5 note cards (any card stock or thick paper, use what you have)
- A safety or straight pin
If you don't have note cards then card stock is readily available all over. I love to use cereal boxes. If you have a ceral box on hand then you could make a full scale pinhole projector also.
Step 1: Poke the Hole
Using the pin, poke a hole in the center of the card. Try to keep the hole clean and round. Make sure there are no hanging chads to spoil your good time.
Step 2: Project the Image
The Camera Obscura works similar to a lens. The image of the sun will be projected through the hole to whichever surface is behind it. The good news is that it should give an image at any distance. The bad news is that the larger the image the fainter it is.
Hold the card to form a shadow on the second card. Try to limit any other light sources that will show around the card. The darker the shadow the better.
Look for the spot of light from the pin hole. If you look closely you can easily make out the projected image. Seeing as I am so late to the game here, it is already night time, so the projected image here is the CFL in my desk lamp, but the principle is the same.
For the Transit of Venus, look for a spot that is slowly moving across the face of the Sun. If you are viewing an eclipse, look for the scary monster eating pieces from the Sun and hope he gets indigestion.
You can find your local times for the transit here: http://transitofvenus.nl/wp/where-when/local-transit-times/
In a real pinch, hold your hands over eachother and open a gap between your middle and ring fingers to form a pinhole.