Four Tips for Choosing Telescope Eyepieces

If you are serious about astronomy, then it's a good idea to have multiple telescope eyepieces. There are a few things you should consider before choosing these eyepieces. Some of these include barrel diameter, eye relief, and field of view. This article will give you a few tips for choosing telescope eyepieces.

Barrel Diameter

One of the first things you need to consider when choosing telescope eyepieces is the diameter of the barrel. The smallest diameter you can find is 24.5mm, but these are commonly used on cheap designs. The most popular telescope eyepieces have a barrel diameter of 1.25 or 2 inches. Barrels with a diameter of two inches will have an opening that is more than twice as large as a barrel that has a 1.25 inch diameter. Also, you should be aware that if the barrel diameter is too small, it may restrict your apparent field of view.

Eye Relief

One of the next things to consider when choosing telescope eyepieces is eye relief. Eye relief is the distance your eye needs to be from the top of the eyepiece in order to see the complete field of view. If you wear glasses, then you should avoid telescope eyepieces with less than 10mm of eye relief. Most users look for telescope eyepieces that have at least 15mm of eye relief.

Apparent Field

You will also need to think about the apparent field of view when choosing telescope eyepieces. This refers to the angle at which you have to turn your eye in order to switch from one side of the field of view to the other side. Telescope eyepieces have different apparent field of view. The lowest can measure 30 degrees, while other designs can measure more than 80 degrees.

Barlow Lens

One of the next things you should consider when choosing telescope eyepieces is a Barlow lens. A Barlow lens can be used with your eyepieces in order to increase their magnification. If you use a 2x Barlow lens with your telescope eyepieces, the magnification will increase twice as much. Barlow lenses can multiply the magnification from 1.75 to as much as 5.0. Also, some designs will allow you to adjust the ratio at which the Barlow lens magnifies the image.