Baader ASTF and ASSF solar filter films are recommended for those looking for a no-compromise and extra-safe solution for observing the sun.
The solar filter of course includes Baader's highly popular and high quality ND 5.0 film optimized for visual purposes. The filter's mount is made of metal and has holes for attaching the filter to telescopes of different diameters by inserting "mounting pins". The package includes a set of self-adhesive Velcro to quickly and securely attach the solar filter foil to the front of the tube. For Newtonian telescopes and lens-based instruments, the filter can be attached to the tube/helmet from the inside or outside, for SC/MC telescopes it is recommended to do this from the outside only.
In the ASTF series, the filter is mounted in a temperature compensating mount which expands and contracts with the solar filter film in line with temperature changes to ensure that the film is always sufficiently "tight" to provide the best possible image quality.
The table below shows the sizing of Baader ASTF / ASSF filters. External diameter should be observed if you want to mount the filter on the outside of the tube, internal diameter if you want to mount the filter on the inside.
| Model | Free View | Outer diameter | Interior diameter |
| 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 |