Partial Eclipse

Observation of the partial solar eclipse can be very dangerous if you do not have a suitable filter ready that would reduce the intensity of the sunlight. The mere fact that a filter seems to be dark enough and that you can view the Sun through it without being dazzled is no guarantee that the filter is safe and your eye-sight cannot be permanently damaged. This is because the filter may be transparent for wavelengths invisible but dangerous to the human eye (for example infrared radiation). An example of such a dangerous filter might be a developed color film. The black part of the film opaque for visible light is perfectly transparent for infrared radiation. On the other hand, a sufficiently dark, black-and-white film is safe. The best solutions are the filters designed especially for observation of the Sun and dark glass used in welding. The magnetic disks of computer floppies, if sufficiently dark, also possess favourable properties. I used a large floppy disk to make a filter for the MTO 1000a lens which helped me to safely find the Sun before the beginning of totality. When viewed through the filter the Sun has a deep red color as you can see on the photograph.