Focal length: 40mm
Barrel Diameter: 31.7mm (1.25″)
Apparent Field: 43°
Eye relief: 28mm
Field Stop Diameter: 27mm
This is a very good low power/wide field eyepiece. With 43 degree apparent field it provides the widest field possible from a 1.25” eyepiece. It’s ideal for large open clusters, emission and reflection nebulae, large and faint nebula remnants such as the Vela Supernova Remnant and galaxy clusters.
The rubber grip gives sure grip and makes it comfortable to use in cold weather.. 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.
In scopes that are longer than f/6, it will give you the widest and brightest field possible from a 1.25” focuser telescope.
The 28mm of eye relief makes it a good choice for eyeglasses wearers. It’ s parfocal with the shorter focal length Plossls. Filter threads to fit your filters and blackened lens edges.