Optolong 3nm L-Ultimate Filter - 2" type-telescope-eyepieces the Caldwell Catalog

the Caldwell Catalog

f/7 focal ratio

BONUS Astronomy Software download with a 10

4" Maksutov-Cassegrain Telescope

black housing and 2" ClickLock clamp) as well as on the BBHS® T-2 Sitall Stardiagonal (#2456103) - where the housing features a male and female T-2 thread - for shortening the optical path with bino use

Optolong 3nm L-Ultimate Filter - 2" type-telescope-eyepieces the Caldwell CatalogThe Optolong L Ultimate 3nm dual band filter is designed to drastically reduce the effects of light pollution. The 3nm isolates the nebulae's emissions into H Alpha (red) and OIII (green blue). It blocks light pollution, maximizes the signal from nebulae, and darkens the sky background. It also blocks artificial light from mercury vapor lamps, high and low pressure sodium vapor lights, and unwanted natural light caused by the emission of neutral