Celestron UHC/LPR Filter - 1.25''. This includes mercury vapor and both high and low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. sky glow). Celestron CPC Accessory Kit comes with Celestron UHC/LPR Filter 94123 Celestron Telescopes AC 110v 18778 Celestron Telescope Power Tank 18774 and Celestron T-Adapter 93633-A Celestron UHC/LPR Filters: Celesteon UHC/LPR Filter - 1.25" (item 94123) Celestron UHC/LPR Filter - 2" ( model 94124) The new Celesteon UHC / LPR Filter has improved contrast over the typical broadband filters. Sky background is darker and contrast of emission nebulae are noticeably improved. The advanced technology coatings enable Celestron UHC LPR Filter to achieve an outstanding transmission of over 97percent across the entire bandpass with total blockage of prominent light pollution lines. Celestron Ultra High Contrast Light Pollution Reduction Filter (UHC LPR) is the perfect filter for viewing nebula from light polluted skies or for boosting the contrast of nebula from dark sky sites. In addition to it's optimum spectral and optical characteristics UHC/LPR Celestron Filters offer important features that set them apart and result in the highest quality celestial views: Features of Celestron UHC/LPR Filters: The multi-layer dielectric coatings are plasma assisted and Ionbeam hardened using the latest technology for durability and resistance to scratching. Improved transmission translates to maximum image brightness and contrast. Users of smaller 4"-11" telescopes will especially appreciate the high efficiency and larger scope users will love the rich star fields and detailed subtle nebular shadings that are left intact. The high transmission sharp cutoffs and more moderate 60nm passband of the UHC/LPR filter retains a more natural view yet significantly boosts overall contrast. Imagers will appreciate the broader bandpass and inclusion of an extremely efficient H-Alpha passband (656nm) Package Contents: Celestron Ultra High Contrast Light Pollution Reduction Filter (Celestron UHC/LPR Filter)