DeltaOptical Plossl 20mm 52° 1.25″ eyepiece

The DeltaOptical Plossl 20mm is a versatile optical accessory designed for visual observation of astronomical objects. Thanks to the classic Plossl design, it is fully compatible with any telescope featuring a standard 1.25″ eyepiece barrel and suits both beginners and experienced observers alike. The 52° field of view provides a comfortable overview when observing planets, the Moon, star clusters, and nebulae.

Optics and image quality

Multi-layer anti-reflection coating on all optical surfaces significantly reduces unwanted light reflections, increases light transmission, and delivers a sharp, bright, and high-contrast image with minimal aberrations. The Plossl optical system is built from two symmetrical doublets, which ensures excellent correction of chromatic and spherical aberrations across the entire field of view. The result is an accurate and detailed rendering of astronomical objects free from disturbing optical artifacts.

Focal length and application

The 20mm focal length makes this eyepiece ideal for medium magnification, which is perfect for observing extended deep-sky objects such as open star clusters or large nebulae, as well as for general views of the Moon and planets. The eyepiece fits directly into a standard 1.25″ focuser without any adapters. The built-in eye guard makes comfortable observation easy even when wearing glasses.

Reliability and value

DeltaOptical Plossl series eyepieces are designed as reliable and affordable accessories that meet the demands of optical quality and mechanical durability for everyday use both in the field and indoors.

Key features at a glance

Classic Plossl optical design - two symmetrical doublets
Focal length: 20mm
Field of view: 52°
Barrel diameter: 1.25″
Multi-layer anti-reflection coating on all optical surfaces
Eye guard for comfortable viewing with or without glasses
Compatible with any standard 1.25″ focuser - no adapters needed
Suitable for planets, the Moon, star clusters, and nebulae

Specifications

Parameter	Value
Focal length	20mm
Field of view	52°
Barrel diameter	1.25″
Optical design	Plossl (2 symmetrical doublets)
Coating	Multi-layer anti-reflection on all surfaces
Eye guard	Yes

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This product is available in the following variants:
Eyepiece Delta Optical Plossl 4mm 52° 1.25″	35.65 €
Eyepiece DeltaOptical/GSO Plössl 12mm 52° 1.25	38.10 €
DeltaOptical Plossl 20mm 52° 1.25″ eyepiece	39.15 €
DeltaOptical/GSO Plössl 15mm 52° 1.25″ Eyepiece	41 €
Eyepiece Delta Optical Plossl 6mm 52° 1.25″	41 €
Eyepiece Delta Optical Plossl 40mm 45° 1.25″	45.15 €
Eyepiece Delta Optical Plossl 9mm 52° 1.25″	45.35 €
DeltaOptical Plossl 32mm 52° 1.25″ eyepiece	48.85 €

DeltaOptical Plossl 20mm 52° 1.25″ eyepiece