|
|
What are the facts about eyepieces?
Home » Astronomy » Adding Equipment » What are the facts about eyepieces?The eyepiece is the magnifying part of your telescope. They are measured by the diameter of the barrel and their focal length in millimeters. Focal length—be it an eyepiece or a telescope—is the distance the light must travel to come to the point of focus.
Some beginning model telescopes come with .965" barrel eyepieces that are generally poor quality and difficult to upgrade. Look for models that include 1.25" barrel sizes. Eyepieces with a longer focal length, such as 25mm, give less magnifying power and a wider field of view, while the shorter 5mm is extremely high power with a very restricted area. Magnifying power (such as 100X) is a simple equation. Divide your telescope’s focal length (printed on the side) by the focal length of the eyepiece (printed on its side). Too much power can mean a large, blurry image. All telescopes have practical limits of magnification.
While eyepieces come in a huge array of styles and optical designs, the bottom line is—you get what you pay for. While an expensive eyepiece will not turn a bad telescope into a good one, it will turn a good telescope into an awesome one.
Chances are your new telescope will include both a 25mm and a 10mm beginning eyepiece which is very satisfactory. As you progress in your hobby, you’ll eventually add more and experimentation with differing designs will give you experience.
Remember, a telescope depends more upon its light gathering ability rather than its magnifying power.
Related Adding Equipment Articles
- Adding Equipment - Introduction
- What type of equipment do I really need?
- What are the facts about eyepieces?
- What is a barlow lens?
- Do I need special filters?
- How can I observe the Sun safely?