Sun projection method
The sun projection method is an observation method in astronomy and results from the use of a telescope (usually a Fraunhofer refractor ), which throws the incoming light from the sun through an eyepiece onto a projection surface (for example a piece of white cardboard).
application
This projection surface is placed at a distance of about 30 cm from the eyepiece. There, the image of the sun is brought into focus using the telescope's focusing unit. The great advantage of this observation method is that the object can also be observed by groups. With this method, the sun can be observed without hesitation, as one does not look directly into the glistening light.
Hazard warnings
Even with this method of observing the sun , the telescope must never be left unattended. Children could rotate the telescope's eyepiece and look directly into it. The eye would be helplessly exposed to the full and concentrated solar radiation through the lens and the eyepiece of the telescope. Serious eye damage (such as retinal burns) would result, up to and including blindness. The heat can also damage the telescope. Only simple, non-cemented eyepieces should be used, e.g. B. Huygens, Ramsden, Mittenzwey. The lens should also not be cemented. Fraunhofer-type refractors are well suited. Reflector telescopes are unsuitable for this type of observation due to the high temperature of the secondary mirror and can be damaged.