Explore Scientific 72° ED Series 40mm Waterproof Eyepiece

Explore Scientific 72° ED Series 40mm Waterproof EyepiecePlssl and Kellner eyepieces shipped with most telescopes get the job done, but they leave performance on the table narrow apparent fields, limited eye relief, and visible chromatic aberration at the field edge. The Explore Scientific 72 ED Series 40mm Waterproof Eyepiece is a genuine HOYA FCD1 extra low dispersion glass eyepiece with a 72 apparent field of view, waterproof argon purged construction, and long eye relief a meaningful optical upgrade

Plössl and Kellner eyepieces shipped with most telescopes get the job done, but they leave performance on the table — narrow apparent fields, limited eye relief, and visible chromatic aberration at the field edge. The Explore Scientific 72° ED Series 40mm Waterproof Eyepiece is a genuine HOYA FCD1 extra-low dispersion glass eyepiece with a 72° apparent field of view, waterproof argon-purged construction, and long eye relief — a meaningful optical upgrade that transforms what you see through your telescope.

The FCD1 ED glass sharply reduces chromatic aberration compared to standard eyepiece designs, producing cleaner star points and higher contrast across the field. The 72° apparent field of view is wide enough to create a panoramic, immersive viewing experience without the weight and expense of ultra-wide designs. Argon purging prevents internal fogging in humid conditions, and the waterproof housing means dew-soaked nights won't damage the optics.

Key Features

• HOYA FCD1 extra-low dispersion glass — reduced chromatic aberration for sharper, higher-contrast views
• 72° apparent field of view — immersive wide-field viewing without tunnel vision
• Waterproof and argon-purged — sealed against moisture, fog-proof in all conditions
• Long eye relief — comfortable extended viewing for both eyeglass wearers and unaided observers
• 2" barrel — wider format for maximum light throughput and field stop diameter
• Enhanced multi-layer deposition coatings on all air-to-glass surfaces for maximum light transmission

Ideal For

Maximum field, minimum magnification — designed for the widest possible views through fast-ratio telescopes. An excellent upgrade from stock Plössl eyepieces for observers who want wider fields, better eye relief, and the optical clarity that ED glass provides. Compatible with any telescope accepting 2" eyepieces.