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Projection of the Sun with binoculars

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Using ordinary binoculars, it’s an easy matter to project the Sun’s image onto a screen made of white cardboard.
Photo: Espace pour la vie
Projection with binoculars
  • Projection with binoculars
  • Projection with binoculars
  • Projection with binoculars
  • Projection with binoculars

A safe and easy way to observe the Sun or a solar eclipse is to project the Sun’s image onto a screen made of white cardboard using ordinary binoculars.

How to project the image of the Sun with binoculars?

Obviously, you can’t look through the binoculars to find the Sun. However, you can use the shadow cast by your binoculars to centre the Sun. Once the Sun’s image appears on the screen you can sharpen it using your binoculars’ focussing knob. It is preferable to block one of the two objective lenses; otherwise two overlapping images will form.

The longer the projection distance, the larger the image will be, but it will also appear softer. You should experiment to find the ideal distance for the most satisfying image. A projection distance of 1 to 2 metres usually produces good results.

A tripod and a sunshade to improve the projected image

Image stability is also important. Mount your binoculars on a camera tripod. If your binoculars don’t have a mounting socket, they can be attached to a tripod using strong elastic bands or tape. Avoid last minute trials: Test your set-up beforehand!

Lastly, you can construct a sunshade by cutting two holes in a large sheet of cardboard and slipping the objective lenses through. This will cast a shadow on the screen, thereby improving the contrast of the projected image.

 

Warning!
Never leave this apparatus unattended: No one must ever look through the eyepiece while the instrument is pointed at the Sun.