Observation of Solar Eclipse

The strong sunlight would cause blindness if an observer looks at the Sun directly. For solar eclipse with relatively large magnitude, a safe method (see Note 1) to observe the solar eclipse is to project the solar eclipse image through a pin-hole device onto a white cardboard and look at the projection (see Figure 1).  A telescope can be used to replace the pin-hole device to produce clearer images but the observer must ensure that he/she looks at the cardboard only.

Figure 1     Observation of solar eclipse by projection

 

Note:

1. For solar eclipse with very small magnitude, e.g. the partial solar eclipse observable in Hong Kong on 20 April 2023, it would be difficult to use a pin-hole device to view the solar eclipse. Other effective methods of viewing can be made reference to NASA's webpage for solar eclipse safety (https://solarsystem.nasa.gov/eclipses/safety/).