A Guide to Light-Pollution Filters for Visual Astronomy
- 1. Overview
- 2. How Light Pollution Filters Work
- 3. Types of Light-Pollution Filters
- 4. Filter Bandwidths, Exit Pupils, and Image Brightness
- 5. Recommendations for Light Pollution Filters
- 6. Summary
- 7. Further Reading
1. Overview
"Always avoid the neighborhood of any bright light. Electric lights in particular are an abomination to stargazers." These prophetic words by the astronomy writer Garrett Serviss in his 1896 book Astronomy with an Opera Glass continue to ring true. All modern cities are now enveloped in a dome of scattered light pollution to the extent that entire constellations are rendered invisible by the glow of street and building lights, and many city dwellers are entirely