TeleVue 40mm Plössl Eyepiece

This is a very good low power/wide field eyepiece that provides the widest field possible from a 1.25" eyepiece. Its field stop (the rim inside the eyepiece that determines the field of view) is the inside of the eyepiece barrel itself, so you'd have to go to a 2" eyepiece to get a wider field of view. It's ideal for capturing galaxy pairs and galaxy clusters, viewing emission and reflection nebulas in their entirety, scanning large and faint nebula remnants such as the Veil, etc. You can use the calculator below to see how wide a field it will give you with your particular scope. It has a rubber grip ring for comfortable use in cold weather. It provides a huge 8.9mm exit pupil with an f/4.5 Dobsonian reflector. As the eyes of most observers are unable to dilate to this size, this eyepiece will probably waste a good portion of the light-gathering capacity of a fast focal ratio scope. It is better suited to the longer focal ratios of refractors, Schmidt-Cassegrains, and Maksutov-Cassegrains than it is to reflectors with focal ratios shorter than f/6. At f/6 and above, it would be an excellent choice to give you the widest and brightest field possible from a 1.25" focuser telescope. The very long eye relief makes it a good choice for those who wear eyeglasses. Tech Details: Barrel Size 1.25" Eye Relief 23mm Field of view 43 Focal Length 40mm Number of optical elements 4 Weight 8 oz Warranty Limited Lifetime