How do I see the Transit of Venus safely?

You should never look at the Sun directly, or through any lens, mirror, telescope, binoculars or any other optics - you can severely damage your eyes or even go blind !

There are many completely safe methods to see the Transit, though - and these can also be used to see a Solar Eclipse too.

Projection through a telescope

If you have a telescope or a pair of binoculars, you can use it to project the Sun on to a piece of paper. It is perfectly safe to look at the paper and hence see the Sun's image. You will be able to see sunspots very clearly as well. Take care not to even accidentally look through the telescope/binoculars while adjusting it. Covering the sheet of paper from the sides to cut out some ambient light will give you a better image.

This method is illustrated (for a solar eclipse) here, here and here.

Eclipse glasses

Ask your nearest planetarium, observatory, astronomy institute or science club for a pair of eclipse glasses. These are not your usual sunglasses ! They are made from special Mylar sheets to cut down the brightness of the Sun by a huge amount. Do not use them if they have holes or seem damaged. You can also use Welders glass #14 or higher if you can get them.

You also get Mylar filters to attach to the front of a telescope, so that you can see through the telescope itself. Unless you can really rely on the quality of your filter, do not use them !

You can ask for them at your Planetarium. If you are in Pune or Mumbai, Navnirmiti stocks quite a few of them.

If you get one, you would look like this, or even as cool as this !

Pin-hole camera

This is the simplest and the most familiar way to see the Sun. However, the size of the Sun's image formed through a pin-hole is roughly 110 times smaller than the distance between the pin-hole and the screen. Hence we need a pin-hole camera atleast 5-8 metres in length !  A 8m long pin hole camera will for a 8 cm sized image of the Sun. Remember, Venus is about 1/30th the size of the Sun. Venus, therefore, will be 2.7 mm big, which can easily be seen.

You may have seen pictures taken during a solar eclipse where the tiny ever-moving pin-holes formed between the leaves of tall trees form very pretty multiple images of the eclipsed Sun, on the ground. Though the image is big enough, the ground needs to be shielded from ambient light. Also, the leaves moving in the breeze will make it a bit difficult to see Venus.

During an eclipse, for example, you would see this or this or even this !

Ball-mirror assembly

The best way to see the Transit is the ball-mirror assembly, a Navnirmiti design. Each one of us can make one, and manage to see Venus extremely well.

Take a plastic ball, say 20-30 cm in diameter. Cut a roughly 1 inch sized hole in it with a knife. Fill more than half of it with sand to make it heavy. Now, close the hole by sticking a piece of paper on it with sticky tape. Get a small flat (plane) mirror from a nearby shop and stick it on the piece of paper. Thinner mirrors will give you better results.

Take another small piece of dark coloured paper and cut a circular hole in its centre, of diameter roughly 2-3 cm. Now stick this on the mirror so that we see only a 2-3 cm wide circle-shaped mirror.

Take this ball outside the house, and place it on a suitable circular stand - this can be the sticky tape ring itself, or even a small vessel from your kitchen. You will notice that you can rotate the ball to make the mirror point in any direction, but friction makes sure that the ball does not rotate on its own. Congratulations - you have now made a ball-mirror mount !

Now use this ball-mirror to project the Sun's image through an open window on to a wall inside your house or school. The distance between the wall and your ball-mirror should be atleast 10 m. If you now darken the room, and make the image of the Sun fall on a white sheet of paper, you can see a beautiful large image of the Sun - you can even make out sunspots, and of course, you will be able to see Venus move slowly across the Sun's disk !

If the image is not sharp enough, cut a 2-4 mm hole in a sheet of paper and hold it in front of the mirror. This pin-hole will then lead to a fainter, but sharper image.

Your assembly will look like this.