Solar filters for observing the Sun

More experienced sun watchers prefer specially designed sunscreens that reduce the sun’s energy to harmless levels. Filters fall into two main categories: First, white light filters. These block 99.999% of sunlight to allow us to see the Sun’s visible surface, or photosphere, revealing magnificent views of ever-changing sunspots. Then come the Hydrogen-alpha (Hα) filters. These block all wavelengths of sunlight except one – the wavelength emitted by hot hydrogen atoms. Hα filters reveal details about the Sun that are invisible using white light filters, including flame-like prominences and intricate glowing threads called solar beaches, which are usually found near sunspots.

White light filters

Known as “aperture filters”, white light filters fit the front of a telescope to reduce solar energy to a safe level before it enters the optical system , including your eyes. They are usually made from glass or a polymeric material, such as Mylar, and fit securely in a telescope or binoculars (although you need two filters for these, one per barrel).

White light filters should only be purchased from a reputable source. Some of the most popular include Astrozap (, Baader Planetarium (, Celestron (, Explore Scientific (, Kendrick Astro Instruments (, Meade Instruments (www., Orion Telescopes ( and Thousand Oaks Optical (

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