Meade Series 4000 Nebular Filters incorporate the very latest in interference coatings technology. Each filter includes more than 40 coating layers to precisely reject unwanted light from urban light pollution while allowing critical nebular emissions to pass through with minimal reduction.
The effect of the filter is that nebular light reaching the eye is observed visually in dramatically increased detail, while the effects of unwanted city lights are greatly reduced. The Meade Broadband Filter also passes photographically-important Hydrogen Alpha nebular light, making the filter a valuable aid in the photography of deep-space emission nebulae. The contrast between galaxies and the night-sky backdrop is typically enhanced by the filter, but because galaxies emit light in a much broader range of wavelengths than nebulae the effect is generally not as dramatic.
Please note that the 1.25" size is recommended for refractor and Newtonian reflector telescopes. For Schmidt-Cassegrain telescopes, the rear cell filter can be more convienent.