Determining the Correct Orion Solar Filter for your Telescope
A full-aperture solar filter is designed to fit over the front of a telescope. It allows safe viewing of the Sun by reducing the light by 99.99% and preventing concentrated heat from entering the telescope, which could cause injury to the user or damage to equipment.

If your telescope is not listed on our solar filter chart, you can determine the size of filter needed for your telescope by taking the following steps:

Measure the maximum outside diameter (OD) of the front end of your telescope.

The solar filter sizes listed on our website refer to the inner diameter (ID) of the filter's foam-lined metal cell for Orion Safety Film Solar Filters, which slip over the front of the telescope. Choose a filter whose size matches the OD of your telescope's front end, or that is up to 0.25 inches larger than the front end.

Installing the Orion Solar Filter on Your Telescope
If your solar filter includes three thumbscrews, back them out to just inside the wall of the metal cell. Alternatively, if your filter includes foam shims, you can install them now to ensure a snug fit. Then place the solar filter over the outside of the telescope. It may require some light force to push the filter into place, but make sure it is seated completely over the telescope. Then lightly tighten the thumbscrews (if included) to further secure the filter on the telescope.