Binorum Super Plössl 20mm 50° SPL 1.25″ Eyepiece

The Binorum Super Plössl 20mm is a high-quality eyepiece with a classic Super Plössl optical design and a comfortable 50° field of view, suitable for everyday observing with almost any telescope. It is a versatile and reliable choice for both beginners and more experienced observers who want sharp, bright, and natural-looking views of the night sky.

Thanks to its modern optical design, this eyepiece delivers excellent image sharpness, good contrast, and accurate color reproduction. It is especially well suited for observing the Moon and planets, but it also performs very well on brighter deep-sky objects such as star clusters and nebulae. The balanced 20 mm focal length provides a pleasant combination of magnification and image brightness, making it ideal for general-purpose observing.

All lens edges are blackened to reduce internal reflections and improve contrast. The eyepiece features fully multi-coated (FMC) optics on all air-to-glass surfaces, ensuring high light transmission, crisp detail, and a clear, high-contrast image. This means you can enjoy brighter views and finer details, even when observing subtle features on the Moon or planets.

A foldable rubber eyecup helps block stray light and improves viewing comfort, whether you observe with or without glasses. The standard 1.25″ barrel makes this eyepiece compatible with the vast majority of astronomical telescopes and focusers on the market.

The Binorum Super Plössl series is available in a wide range of focal lengths, making it easy to build a complete and well-balanced eyepiece set:

6 mm, 6.4 mm, 7.5 mm, 8 mm, 10 mm, 12 mm, 12.5 mm, 15 mm, 17 mm, 18 mm, 20 mm, 25 mm, 32 mm, 40 mm.

If you are looking for a dependable, high-performance eyepiece with excellent value for money, the Binorum Super Plössl 20mm is a great choice for everyday astronomical observing.

Specifications

Type of eyepiece: Super Plössl

Focal length: 20 mm

Connection type: 1.25″

Apparent field of view: 50°

Eye relief: 13 mm

Coating of optical system: FMC

Telescope parameters using this eyepiece

Aperture mm

Focal length telescope mm

Specifications:

Magnification:

Telescope magnification is calculated by dividing the telescope's focal length by the eyepiece focal length. A Barlow lens also affects magnification: the power increases according to the Barlow's multiplication factor.

Field of View:

The field of view is the angular size of the sky area visible through the telescope with a given eyepiece. It depends on both the magnification and the eyepiece's apparent field of view. For comparison, the Moon's average apparent diameter is 0° 31' 5" (0.518°).

Exit Pupil:

The exit pupil is the diameter of the light beam that exits the eyepiece and enters your eye. A larger exit pupil produces a brighter image. Exit pupil is calculated by dividing the aperture diameter by the magnification.

Focal Ratio:

The focal ratio (also called f-number or f-stop) is the ratio of the telescope's focal length to its aperture diameter. Telescopes with focal ratios from f/4 to f/6 are typically called "fast" telescopes, suitable for both visual observation and astrophotography. Telescopes with focal ratios between f/6 and f/15 are better suited for visual observation than photography, and generally make it easier to achieve higher magnifications.

Resolution (Dawes Limit):

Resolution is the angular size of the smallest details and objects that can be distinguished through this telescope under excellent observing conditions. This theoretical limit assumes perfect optics and atmospheric conditions.

Limiting Magnitude:

This is the faintest star magnitude visible through this telescope under excellent observing conditions with dark, clear skies and a fully dark-adapted eye.

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This product is available in the following variants:
Binorum Super Plössl 12.5mm 50° SPL 1.25″ Telescope Eyepiece	40.40 €
Binorum Super Plössl 6mm 50° SPL 1.25″ Eyepiece	44.30 €
Binorum Super Plössl 6.4mm 50° SPL 1.25″ Eyepiece	44.50 €
Binorum Super Plössl 7.5mm 50° SPL 1.25″ Eyepiece	44.70 €
Binorum Super Plössl 8mm 50° SPL 1.25″ Eyepiece	44.90 €
Binorum Super Plössl 10mm 50° SPL 1.25″ Eyepiece	45.15 €
Binorum Super Plössl 12mm 50° SPL 1.25″ Eyepiece	45.35 €
Binorum Super Plössl 15mm 50° SPL 1.25″ Eyepiece	46.15 €
Binorum Super Plössl 17mm 50° SPL 1.25″ Eyepiece	46.35 €
Binorum Super Plössl 18mm 50° SPL 1.25″ Eyepiece	46.55 €
Binorum Super Plössl 20mm 50° SPL 1.25″ Eyepiece	46.80 €
Binorum Super Plössl 25mm 50° SPL 1.25″ Eyepiece	49.25 €
Binorum Super Plössl 32mm 50° SPL 1.25″ Eyepiece	50.05 €
Binorum Super Plössl 40mm 50° SPL 1.25″ Eyepiece	52.95 €

Binorum Super Plössl 20mm 50° SPL 1.25″ Eyepiece