After years of R&D we have developed a new solar film that has the optical quality of glass with the advantages of impregnated polymer. Will never develop pinholes or scratches that can let in light and ruin a filter. Other advantages: lightweight and does not require re-balancing tube assembly, will not break, consistent yellow-orange solar image, even density with any aperture, flat surface compared to other thin film filters that have wrinkles and creases. Will not tear or puncture. Stronger than any other solar film on the market. Also available in sheets. Guaranteed 15 years.
What Size Do I Order?
To ensure the best fit for your application, it’s essential to measure the outside diameter (O.D.) of your telescope or lens. We cannotrecommend a filter size based on the model number of your telescope/lens, so please take the following steps to find the correct size:
- Remove the protective cap/cover that covers the objective glass on the end of your telescope/lens.
- Measure the O.D. of your telescope tube or binocular barrel at its widest point, taking into account any obstructions/taper within 1 1/4in from the end of the tube.
- Select the appropriate O.D. range for your measurement using the dropdown menu above. The dropdown menu lists the O.D. ranges available for our filter sizes and will point you to the correct part # for your O.D.
- Note: The O.D. ranges account for the minimum clearance require for the filter to fit.
Alternatively:
- Choose the closest cell O.D. that is at least 1/16″ (1.58mm) larger than the O.D. measurement of your instrument. For example, if your O.D. measurement is 4″(101.6mm), choose a cell with an O.D. of 4-1/4″(107.9mm) part # S-4250.
- Avoid selecting a size that is the same as your O.D., since it will be too tight
- Note: The 1/16″ of clearance is factored into the O.D. ranges in the dropdown menu above.
The solar filter comes with self-adhesive felt for custom fitting, but you can also find additional felt, Velcro, or other materials at most fabric or home improvement stores.
Please use the size chart below to select the appropriate size for your application. The chart lists sizes by clear aperture (filter size in the center of the cell) and O.D. of the aluminum cell (inside cell wall that fits over and around telescope tube). Please note that we cannot take orders for felt.
OPEN TRUSS TELESCOPES:
If the solar filter is to be used on an open truss telescope, the open area from front (secondary mirror) to back (primary mirror) must be covered. No direct sunlight should enter the optical path or the concentrated beam from the mirror can focus on the back of the solar filter film and cause damage and void warranty.
