Fine lines or webs used in the focal plane eyepiece are called Reticle. It is used for centering objects or as a guide for making angular measurements. It is commonly used for telescopes, cameras and even rifles. It is also known as graticule. The lines on the reticle are also typically illuminated.

One of the most important features or power of a telescope is its capability of showing us the smallest details along with clear, sharp images of the object that we are viewing. This is what’s referred to as its resolving power. There are certain celestial objects that are too close together that they tend to blur into a single image if you were to use a particularly low-powered telescope.

A refracting telescope is one of the earliest tools used by astronomers from way back to study outer space and distant objects. It is one of the two kinds of optical telescopes and uses a lens as the light gathering part or the objective as opposed to a mirror that is commonly used as the objective by reflecting telescopes.

The term radio telescope can be quite misleading since when you think of a telescope, you think of a device used for viewing objects; while you attribute the word radio with hearing. However, all the discoveries in radio astronomy that people know of today could not have been possible without the trusty radio telescope.

The primary mirror is defined as the light gathering, or refracting surface of a telescope. It is also called as the telescope’s objective. In a reflecting telescope, it either uses a single or a pair of curved mirrors to reflect light in order to form an image based on the location where the said telescope is focused on.

When someone mentions astronomy, what often comes to mind are planets and stars seen through a telescope. Astronomy is indeed the study of heavenly bodies, but it need not be with the use of telescopes and sophisticated instruments. Astronomy can also be studied using just the naked eye, and this was how the early pioneers of this science investigated the heavens and learned much about the stars, planets and galaxies.

Photo by: Rama Creative Commons Not only does astronomy cover different branches of science, it also borrows concepts in fiber optics as well. Objective (optics) is also taken into account when it comes to science, or in this case, astronomy.

There are a lot of things that has been said about our galaxy. There is no doubt that increased magnification would give you a beautiful view of celestial bodies, the Moon, the planets and details of sky objects. To see them properly, a Rich field telescope would come in handy. This is a fast focal ratio reflector that gives wide-angle views of star clouds, nebulas and large galaxies.

Photo by: ArtMechanic Creative Commons Newtonian telescope is a kind of reflecting telescope that has a concave primary mirror and a flat secondary mirror. It is patterned after the telescope invented by Sir Isaac Newton, the famous British astronomer and scientist who during the 17th century.

Photo by: Tamasflex Creative Commons The eye relief is an important concept in the use of equipments like a telescope, microscope, or binoculars. By definition, eye relief is the distance from the eye piece at which the eye can be placed to the entrance pupil of the eye. Instruments with short eye relief will require the observer to press their eyes closer to the eye piece to see a clear image.