We recommend Baader ASTF and ASSF mounted solar filter films to anyone looking for a no-compromise, exceptionally safe solution for solar observation.
The solar filter naturally features Baader's highly popular, excellent-quality ND 5.0 film, optimised for visual use. The filter cell is made of metal and has holes for inserting retaining pins, allowing it to be fitted to telescopes of various diameters. The package includes a set of self-adhesive Velcro strips, enabling the solar filter film to be attached quickly and securely to the front of the optical tube. For Newtonian telescopes and refractors, the filter can be secured to the outside or inside of the optical tube/dew shield; for SC/MC telescopes, external mounting is recommended only.
In the ASTF series, the filter is housed in a temperature-compensating cell that expands and contracts together with the solar filter film as temperatures change, ensuring that the film always remains suitably taut for the best possible image quality.
The table below shows the dimensions of Baader ASTF / ASSF filters. Use the outer diameter when mounting the filter on the outside of the optical tube, and the inner diameter when mounting it on the inside.
| Model | Clear aperture | Outer diameter | Inner diameter |
| ASSF 65 | 65 mm | 70 – 85 mm | 96 - 111 mm |
| ASTF 80 | 80 mm | 100 - 140 mm | 130 - 170 mm |
| ASSF 80 | 80 mm | 85 - 100 mm | 111 - 126 mm |
| ASTF 100 | 100 mm | 120 - 160 mm | 120 - 190 mm |
| ASSF 100 | 100 mm | 105 - 120 mm | 131 - 146 mm |
| ASSF 130 | 130 mm | 148 - 178 mm | 168 - 198 mm |
| ASTF 140 | 140 mm | 160 - 200 mm | 190 - 230 mm |
| ASSF 150 | 150 mm | 168 - 198 mm | 188 - 218 mm |
| ASTF 200 | 200 mm | 220 - 260 mm | 250 - 290 mm |
| ASTF 240 | 240 mm | 260 - 300 mm | 290 - 330 mm |