Astronomik H-beta visual 1.25" (M28.5)
Key specifications
| Filter type | Narrowband |
|---|---|
| Passband | H-beta 480-492nm |
| Bandwidth | 12 nm |
| Filter size | 1.25" |
| Mounted | Yes |
About
A visual H-beta filter that passes the 486 nm line almost unobstructed and blocks the rest of the spectrum, lifting faint hydrogen regions like the Horsehead into reach of 10"–12" apertures. Intended for telescopes of 8" and up at f/4.5 to f/6, and of no use under urban skies.