Telescope eyepieces

The optical system is the most important part of any telescope, and the eyepiece is just one of them. The eyepiece affects the field of view, and it also impacts the magnification of the image in the telescope. These parameters have a huge bearing on the quality of observations made with telescopes. Without eyepieces, the telescope loses its most important functions. It becomes impossible to view planets and stars. For this reason, the quality of the telescope eyepiece and its parameters are key elements, along with the telescope lens or mirror, in any optical device.

What is the purpose of a telescope eyepiece?

Telescope eyepieces are accessories through which we can look into space. How much we see is determined by the eyepiece's field of view. Astronomical eyepieces can also be replaced and their parameters adjusted to suit your current needs. In this way, you can also change the parameters of the telescope itself. So let's move on to how the eyepiece affects the optical system of telescopes and their capabilities.

Telescope eyepiece - parameters

The right quality eyepiece for a telescope provides successful observation of the planets and other celestial bodies. Its field of view should contain the desired objects, so the quality of the optics is very important. It can be determined by the optical parameters of a particular eyepiece.

What is the field of view?

The most important parameter of any telescope eyepiece is the field of view. It determines what image is seen by the non-moving eye. Thus, the field of view determines what area of a particular object or space you will be able to see. A larger field of view provides a wider range of observation.

Output field vs. right field

Each eyepiece manufacturer provides an output field of view, which depends on the type of eyeglasses. However, this is not a definitive parameter. You need to perform a few more mathematical operations to calculate the correct range of field of view that can be achieved in a given telescope with a particular eyepiece. To do so, divide the field of view by the magnification that the telescope can achieve with a particular eyepiece.

Telescope magnification vs eyepiece

The optics of the telescope eyepiece, specifically its focal length, also affects the magnification of the image in the telescope. You need to calculate it yourself: the focal length in the telescope divided by the focal length in the eyepiece gives us the total available magnification in optical devices.

What is the lowest magnification?

The lowest magnification is also related to the eyepiece. It is determined by the diameter of the exit pupil. The exit pupil is the area you are looking at, and its diameter should not be larger than the diameter to which the human pupil can expand, which is about 6 mm. When you put your eye to the eyepiece, the area of the exit pupil is projected onto the retina by the distance of the eye pupil. An exact match between the pupil of the eye and the pupil of the telescope allows you to conduct observations of the planets, as well as other celestial bodies. Optimum image quality is achieved with a diameter of about 2-2.5 mm.

Types of telescope eyepieces

There are various types of telescope eyepieces with fields of view of different ranges available on the market. This affects the quality of observation we can make with them. Let's focus on those eyepieces whose optics are of high quality, while they also have affordable prices. They are quite popular telescope accessories, and according to the opinions of various users, they really work well for observing planets and stars.

Choosing a telescope eyepiece

Very popular and inexpensive is the Kellner eyepiece with a field of view of 40 degrees. Even better is the Plossl eyepiece with a field of view of 50 degrees. Its improved version is the Super-Plossl series with a field of view of 52-54 degrees. It might seem that a difference of a few degrees will not make a big difference, but in this case it really matters. SWA is a modern series of very professional and expensive Erfle eyepieces, which are used even in a research center. The eyepiece of this series can also be expensive, but recently there has been a SWA offer with more affordable prices. In this case, we can talk about a field of view of up to 80-90 degrees.

What are the best telescope eyepieces?

Telescope eyepieces are interchangeable accessories that can be adjusted as needed. Their changes are even required for example, when you want to achieve a certain magnification. It is good to have at least three, good quality eyepieces, which are also reliable according to the opinions of various users. An eyepiece with a larger field of view provides a better quality of observation, so it is best to buy equipment that is a little more expensive, but also provides a great experience. A Plossl or Super-Plossl eyepiece will work very well in this role. SWA prices are much higher, but the joy of observation is also much higher with them.

Our store offers astronomical telescopes and accessories from respected brands like Celestron and Opticon. You will also buy optical equipment from us that will improve the performance of your telescope. If you care about seeing more and farther, be sure to invest in a good quality telescope eyepiece.