There are three meaningfully different types of refractor telescopes defined by the glass chemistry and optical design used to correct light. The primary dimension that separates these types is how the telescope manages chromatic aberration, which is the tendency of the glass to split white light into a spectrum of colors. This distinction determines whether a telescope is a simple, low-cost tool or a high-contrast instrument capable of resolving fine planetary details.
What is an Achromatic Refractor?
An achromatic refractor uses two lens elements to bring different wavelengths of light into focus at the same point. This design is the standard for entry-level and budget-conscious setups because it keeps the telescope’s physical length and weight manageable while providing a usable view of the moon and brighter deep-sky objects.
Achromatic refractors are for users who prioritize ease of use and portability over extreme optical precision. They provide a wide field of view and a bright image, making them suitable for observing large nebulae or star clusters. However, they give up on color purity. Because the glass cannot perfectly align all colors, you will see a purple or blue fringe around bright objects like the moon or Jupiter.
In terms of pricing, achromatic refractors sit at the lowest end of the market. They provide the most accessible way to enter the hobby with a telescope that offers significantly more magnification than a pair of standard binoculars.
Where these choices show up in our reviews
Prices across these 3 run from $149.99 to $339.99; each one has a full review here.
Celestron AstroMaster 90AZ Refractor Telescope
$188.88 price checked August 2026
If you are just starting your journey, see our comparison of the best refractor telescope for beginners.
90mm Aperture 800mm Refractor Telescope with AZ
For those seeking a compact setup, explore how the best 70mm refractor telescope compares.
$149.99 price checked August 2026
What is an Apochromatic (ED) Refractor?
An apochromatic refractor, often called an ED (Extra-low Dispersion) refractor, uses specialized glass to correct for chromatic aberration across more wavelengths of light. This design is the professional-grade benchmark for high-contrast planetary and lunar imaging.
Apochromatic refractors are for users who require sharp, color-accurate images of planets and double stars. They excel at providing a “true” white appearance for the moon, free from the color fringing found in cheaper models. The trade-off is the cost of the glass and the complexity of the lens assembly. These telescopes are significantly heavier and more expensive than achromatic versions of the same aperture.
These refractors sit in a much higher price band. While an achromatic refractor might be a weekend tool, an apochromatic refractor is often the primary instrument for someone seeking high-resolution imaging or high-magnification viewing.
Selecting the right optics is easier when you learn how to choose your refractor’s focal length.
What is a Triplet Refractor?
A triplet refractor uses three lens elements to achieve apochromatic correction while maintaining a compact tube length. This design combines the optical excellence of an apochromatic refractor with a more compact physical footprint.
Triplet refractors are for users who want the highest possible optical performance but need to keep the telescope’s size practical for transport or mounting. They offer the best correction of color fringing and provide very flat fields of view, which is essential for wide-field photography. They give up simplicity and weight; because they use three lenses instead of two or one, they are often the heaviest and most complex refractors to manufacture.
Triplet refractors occupy the highest price bracket among refractor types. They are the premium choice for those who want to eliminate almost all optical flaws at the expense of a higher investment and a more substantial piece of hardware.
Refractor Telescope Comparison
| Refractor Type | Best-Fit Buyer | Main Advantage | Main Compromise |
|---|---|---|---|
| Achromatic | Beginner / Budget-conscious | Low cost and portability | Visible color fringing |
| Apochromatic (ED) | Planetary observer | High color accuracy | Higher price point |
| Triplet | High-end imager | Superior flat field | Significant weight/cost |
How do you know which refractor type fits your needs?
You belong in the achromatic category if you are looking for a first telescope to explore the moon and bright deep-sky objects on a limited budget. If your primary goal is to see “something” in the sky and you are not concerned with perfect color reproduction, the achromatic refractor provides the most value for the price.
You should consider an apochromatic (ED) refractor if you intend to spend significant time observing planets or double stars. If you find that purple fringing around the moon makes your current view unsatisfying, the extra investment in ED glass is the standard solution to clear up the image.
You should choose a triplet refractor if you are planning to do wide-field astrophotography or if you require the absolute highest level of optical correction available. If your situation involves a need for a flat field across the entire view and you have the budget for premium glass, the triplet is the correct choice.