The first-ever projector for a planetarium was a hollow ball in 1923. It is made of metal with a diameter of 50 cm. In the centre, a bulb glares with 200 W and projects about 4500 stars through the lenses in the conical caps. The simulation of the diurnal motion takes place by the rotation of the projector head around an axis parallel to the Earth's. The projectors for the planets, the sun and the moon are accommodated in the cylindrical cage. It forms an angle of 23.5° to the rotational axis of the star sphere. That first device was installed in the Deutsches Museum in Munich designated only for this geographical latitude at 48°. A second instrument of the same kind incorporated some few refinements like a variation of the latitude between 49° and 68°. It also offered an extra projection for the meridian, the equator and the ecliptic. That copy was set up in Dusseldorf and experienced a journey to Poland and Holland before it retired.