Type of Eyepieces

Types of eyepieces

• Huygens: it was designed in the seventeenth century, and currently only used in low-cost telescopes. The eye relief is short and the apparent field is small.
• Ramsden: it is used from the eighteenth century but today is obsolete.
• Kellner, is of good quality and not very expensive. The images are bright and so detailed at low magnification. They are ideal for use in small and medium-sized telescopes. The apparent field is 40 degrees and the eye relief remains short. Orthoscopic: Images have more detail, correct chromatic aberration and the eye relief is long. They are ideal for lunar and planetary observation.
• Plossl: this is currently the most widely used design provides excellent quality image, the eye relief is long and the apparent visual field of about 50 °. It's great for all types of observation.
• Erfle, have an apparent field of 60 ° to 70 °. In low magnification, ideal for deep space views. At high magnification you lose image quality towards the edges.
• Ultrawide or ultra-wide: these are up to 85 ° apparent field. It loses some brightness slightly greater number of items I have, but the image quality is very high.

The choice of the eyepieces depends on what you want to see and how retailers will be for pictures.

The diameter of the eye is another issue to consider, about 0.965 ", 1.25" and 2 ". Fans generally use 1.25 ". The 2 "are ideal for high-performance telescopes.