Astrozap Solar Filter

You need to measure the outside diameter (OD) of your telescope's front cell or dew shield. This filter is precision-engineered to fit telescopes with an outer diameter between 397mm and 403mm; if your measurement falls outside this range, this specific model will not fit securely.

Yes, this is a full-aperture glass solar filter designed specifically for safe solar viewing. It blocks the vast majority of harmful light, allowing you to observe the sun's surface safely when properly attached to your telescope.

It is compatible with most telescope designs, including refractors, reflectors, Schmidt-Cassegrains, Maksutov-Cassegrains, and Dobsonians. The primary requirement is that the telescope's outer diameter falls within the 397mm to 403mm range.

Glass filters like this one are generally more durable and provide a more natural, yellowish-orange tint to the sun. While film filters can offer slightly higher contrast for some users, glass is often preferred for its longevity and ease of cleaning.

Before every observation session, hold the filter up to a bright light source—not the sun—to check for any pinholes, scratches, or cracks in the glass coating. If you notice any damage that allows light to pass through, do not use the filter, as it can compromise your safety.