$reflector vs refractor telescope$

However, this does render this type of scope impractical for daytime use. This is not a big issue for astronomy purposes, although some people are bothered by this. The reflector design produces an image that is inverted. Light enters from the left, goes to the mirror which is inside the tube on the right, then back up and out to the eyepiece near the front of the optical tube. The picture shows a Newtonian reflector design on a tripod mount.

$reflector vs refractor telescope$

There is no diagonal as the secondary mirror serves this purpose. This secondary mirror is set at a 45-degree angle so the light can be directed to the focuser on the side of the tube. This gathers the light from the sky and focuses it toward a flat secondary mirror that is set part way up the tube. At the bottom of the tube is a curved mirror, called the primary mirror. In this design, we have an open-ended tube. This is how spotting scopes and binoculars are made, which are based on the refractor design. If you want to use your refractor during the day to view boats on the lake or go bird watching, you can get a diagonal that has a prism to correct this left/right flip. For astronomy purposes, this left-right flip is of little importance as there is no left and right in space. For astronomy, you want a 90-degree “star diagonal”.Ī refractor with a diagonal presents an image that is correct up and down but reversed left and right. There are diagonals that use a 45-degree angle but these are better for daytime spotting scope use. The eyepiece is usually inserted into the diagonal. This one is mounted on a tripod.Īstronomical refractor telescopes usually have a diagonal in the light path that bends the light through a 90-degree angle to place the eyepiece at a more convenient position. You see an example of a refractor telescope in the picture. However, if the eyepiece were at the end of the tube and you had the telescope pointed high in the sky you would have to be down on your knees to look through the eyepiece. You could have an eyepiece directly in the path of the light, like a pirate’s spyglass. As it gathers light it bends it and concentrates it to a focal point within the optical tube.

$reflector vs refractor telescope$

What is A Refractor Telescope?Ī refractor telescope has a curved lens on the front. So if you think of a 4-inch aperture as 100 mm, you will be close enough for this discussion. For convenience, you can round that to 25. Telescope aperture is often reported in units of inches or millimeters. For the purpose of this discussion, we will speak of telescopes and optical tubes interchangeably as we can assume the optical tube will be on some kind of mount. Just know that there are a variety of styles of mounts and either type of optical tube can go on any kind of mount. This discussion will be focused on the optical tube, refractor or reflector. When we say telescope we are really talking about two parts – the optical tube assembly and a mount. Focal Ratio – Focal length/aperture usually expressed as F# such as F5 or F10.Focal Length – The length of the path that the light travels in the optical tube.Aperture – The diameter of the front lens or the rear mirror in inches or millimeters.I am going to address that question and hopefully enable you to purchase the best telescope with confidence.įirst, let’s define some terms that I will be using. Which is better for a first-time telescope buyer? What’s the difference between reflector and refractor telescopes?

$reflector vs refractor telescope$

Isaac Newton in the mid-1600 and so it is often referred to as a Newtonian or Newtonian reflector. The mirror sits in the bottom of a tube and the eyepiece sticks out the side. They start their shopping only to discover that there are also reflector telescopes that are based on mirrors rather than a lens. This is the type that was made popular by Galileo in the early 1600s. Most people, looking for their first telescope, will have an image in their mind of a long tube with a lens on one end and an eyepiece in the other.

$reflector vs refractor telescope$

Reflector vs refractor telescope