“White Light” Filters
“White Light” Solar filters are broadband filters which eliminate 99.99…% of all light and are most commonly used with telescopes and binoculars to view the Sun. The inexpensive mylar Solar Eclipse Viewers are also in this class of filter. Views through these kinds of filters show sun spots and on days with especially good atmospheric steadiness, some granularity in the Sun’s surface.
Glass & Mylar
“White Light” filters are generally made from one of two kinds of materials: Mylar a lightweight plastic film or glass. Mylar is lightweight, less expensive and produces good color. Glass is more durable and provides better resolution.
Your should always inspect a solar filter before using making sure there are no scratches or, in the case of mylar filters, tears. Small scratches can usually be painted out with a black permanent marker without affecting the “telescopic” view. Tears or cracks require you to dispose of and replace the filter.
Sometimes called “Solar Prominence” filters Hydrogen-Alpha filters come in filter sets. The first part of the filter set is the Energy Rejection Filter which blocks almost all light which the exception of a narrow band of red light. The second part is a Tuning Filter which allows the filter to be tuned along the narrow red spectrum passed by the Energy Rejection Filter.
H-Alpha filters are used to view Solar Prominences along the edge of the Solar disk.
Dedicated Solar Telescopes & Binoculars
In recent years dedicated optics like Solar Binoculars (like Coronado’s Binomite (white light) and the PST (H-Alpha) have appeared on the market. These dedicated solar optics are design to exclusively be used with the Sun.