Baader Planetarium A4 20x29 cm sun filter foil

It's always very pleasant to observe the Sun, not only during solar eclipses. The number of sunspots changes permanently, as well as their shape and size. Depending on magnification, you may even be able to discern the core and boundary areas of a sunspot (umbra and penumbra). The one essential condition for any solar observation is to reduce the sunlight to under 1/100.000 of its normal brightness, which is a no risk amount for the eyes. The Astro-Solar sun filter foil meets that standard. Simply fitted to the front of the telescope tube, this foil doesn't fall short of pricey plane-parallel glass filters in any way. The coating is subjected to permanent quality control. The multiple metal coating of the foil produces a remarkably even filter effect.