Useful Filters For Viewing Deep-Sky Objects

Useful Filters For Viewing Deep-Sky Objects by David W. Knisely Prairie Astronomy Club One of the biggest breakthroughs in the past 40 years for deep-sky enthusiasts has been the introduction of effective multi-layer interference filters for certain classes of deep-sky … Read More

Filter Performance Comparisons For Some Common Nebulae

By Dave Knisely Light Pollution and various “nebula” filters have been around since the late 1970’s, and amateurs have been using them ever since to bring out detail (and even some objects) which were difficult to impossible to see before … Read More

Observing the Sun in H-Alpha

H-ALPHA FILTERING SYSTEMS: Unlike continuum “white light” observations of the sun, observing the chromosphere requires a very narrow bandwidth filter centered on the Hydrogen Alpha spectral line (6562.8 Angstroms), which not only reduces the intensity of the sunlight to a … Read More

Light Pollution

Lighting Study Design Standards Summary: click here. Light Pollution Fact Sheet Our goal is to encourage quality lighting! We are NOT against night lighting. The 100 inch diameter telescope at Mt. Wilson Observatory, which overlooks the Los Angelas basin, is … Read More