Telescopes and Eyepieces

  • Maruša 

Introduction

With the purchase of a telescope, you also purchase the eyepiece that comes with it. And if you still use it, you might be missing out. Eyepieces come in all shapes and sizes to suit all preferences and prices.

The eyepiece you get with the telescope only provides basic results, but if you purchase another, you might discover a whole new outer world. Like all things in life, you get what you pay for, but eyepieces with wanted qualities can be purchased at a reasonable value if you know what to look for.

Telescopes and Eyepieces

Source: Wikipedia

Eyepieces in General

No one can observe without an eyepiece. An eyepiece, also called the ocular lens, is a lens that is attached to a number of different optics products, for example, telescopes. They are called eyepieces because the observer looks through the telescope through the lens that is closest to the eye. In other words, eyepieces consist of multiple lenses that provide the user to adjust various magnifications on a telescope.

Eyepieces take the gathered light and magnify it. As the lens catches the light, a small part of it is lost. And to make sure not a whole lot of light is lost, companies coat the lenses usually with magnesium or calcium fluoride.

Types of Eyepieces

Plössl Eyepiece

Plössls have a wide field of view, which is about 52°, thus they can be used for observing planets, along with the deep-sky. The disadvantage of Plössls is that they have short eye relief, which can be a problem. The term eye relief relates to the distance of the eye from the eyepiece – the distance it takes for the observer to see the whole field of view. Plössl eyepieces also comprise of two lens systems.

Telescopes and Eyepieces

Plössls Eyepiece (Source: Wikipedia)

Radian Eyepiece

The Radian is a newcomer in the eyepiece market. Their field of view can be compared to that of Plössl, but a big contrast that occurs between the two is eye relief, which is bigger with the Radian eyepieces. Having a bigger eye relief is of big help to those who wear glasses. The Radian eyepiece is manufactured in such a way that it suits medium, as well as higher magnifications so as to the observer sees as many details as possible.

Nagler Eyepiece

The Nagler eyepiece is most known for its large field of view, as they offer an extra-wide field of view of 82°. With this eyepiece, you can observe extremely minor details of celestial objects. This eyepiece includes six elements coated with chemicals we mentioned before, so not a lot of light gets lost during the process. However, these eyepieces can be on the heavier side.

Telescopes and Eyepieces

Source: Wikipedia

Orthoscopic Eyepiece

Orthoscopic eyepieces were on every astronomer’s wish list until Plössls came into the picture. However, this does not mean they are of less quality, as they provide superlative eye relief. Why did Plössls become the more favourable one? Because it has a better field of view. As we mentioned, it has a 52° FOV, while the Orthoscopic eyepiece has a 40° FOV. This is especially helpful when watching the Moon and the planets.

Telescopes and Eyepieces

Source: Wikipedia

Barlow Lens

The Barlow lens is not an eyepiece per se, but it does function as one– it increases magnification. This is done by putting the eyepiece into the lens. This is how the magnification gets doubled or even tripled, depending on the lens.

Telescopes and Eyepieces

Barlow lens (Source: Wikipedia)

Conclusion

Choosing the appropriate eyepiece requires more consideration than one might think. Some say that an eyepiece is the most important part of a telescope. When looking through an eyepiece, you might realize this is true. That you really have been missing out.

Summary
Telescopes and Eyepieces
Article Name
Telescopes and Eyepieces
Description
Choosing the appropriate eyepiece requires more consideration than one might think. Some say that an eyepiece is the most important part of a telescope. When looking through an eyepiece, you might realize this is true.
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Optics Trade Blog
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