OPT's wide selection of refracting telescopes further plants our reputation as the telescope authority! The principal focusing element in a refracting telescope is a lens. Its curved primary (or largest) lens gathers light, bends it, and sends it back to a focal point where it is further modified by the use of another set of lenses called the eyepiece. The curvature and size of the primary lens dictate the amount of distance needed to achieve the focal point. There are a few different types of refractors in the world of astronomy. Apochromatic. Achromatic, Doublet, Triplet, and Petzval are all different types.
These types of refracting telescopes have a better correction of chromatic and spherical aberration than the more common achromat lens. The lenses in an apochromatic telescope will bring light of three different frequencies to a common focus. This should get you a much cleaner view of anything you're looking at in the night sky. If you plan to image with this type of telescope, you will need a field flattener or reducer-flattener. Doing so can get you incredibly crisp images.
The achromatic telescopes are great for solar observing with the correct solar filters of course. Depending on the focal length of the telescope, they can also be great for planetary observing. The key selling point of these telescopes is that they are light and portable, also they are the least expensive type of refractor on the market today.
Doublets, as they are commonly referred to, are simply just refractors that use 2 lenses to get a cleaner and more precise view. These telescopes can also be classified as apochromatic or achromatic depending on the scope itself. These are generally the type of telescopes that you might see at your local sporting goods store because of their cheaper price tag. They also make for great beginner telescopes due to their ease of use, light weight, and cost.
Triplets, as they are commonly referred to, are telescopes with 3 lenses. When compared to doublets, these are more expensive because they tend to be much better at color correction and will give the user a much cleaner view. Triplets are also classified as apochromatic telescopes. If you plan to get deeper into the hobby of astronomy, Triplet Refractors are a great way to go.