Brands - JMI

JMI

Menu

Refractors


Refractors
Refractors are the design that most people associate with a telescope, but they are also the most expensive in terms of dollars per unit aperture. A high quality apochromatic refractor is ideal for both visual observing and astrophotography. The term apochromatic means virtually free of false color. These instruments produce pinpoint stars against a black background.

Most entry level and inexpensive refractors fall into the category of achromatic refractors. These instruments behave much like their more expensive counterparts at low magnification and on objects fainter than Saturn. On brighter objects they will exhibit some false color, or a violet fringe around the object. They also will not reach the same levels of magnification as their more expensive apochromatic cousins. These limitations may not even be noticeable on f/10 instruments, but become more pronounced at faster (lower) focal ratios.

Refractors

Sky-Watcher EvoStar 120mm Doublet APO Refractor
More Details
$1679.00 $1549.00

Free Shipping

On Sale

Sky-Watcher EvoStar 80mm Doublet APO Refractor
More Details
$689.00 $640.00

Free Shipping

On Sale

Sky-Watcher EvoStar 100mm Doublet APO Refractor
More Details
$769.00 $705.00

Free Shipping

On Sale

Stellarvue SV125 Access with Diagonal
More Details
$2134.00

Free Shipping

Celestron AstroMaster 70AZ
More Details
$139.00
Celestron AstroMaster 70EQ
More Details
$149.00
Celestron AstroMaster 90AZ
More Details
$235.00
Celestron AstroMaster 90EQ
More Details
$259.00
Celestron Omni XLT AZ 102
More Details
$289.00
Celestron Omni XLT 102 Telescope
More Details
$499.00 $489.00
Celestron NexStar 102 SLT Telescope
More Details
$469.00
Celestron Omni XLT 120 Telescope
More Details
$649.00 $619.00
Celestron Advanced VX 6-inch Refractor Telescope
More Details
$1439.00

Free Shipping

Explore Scientific ED80 Essential Edition Telescope
More Details
$729.99

Free Shipping

Explore Scientific ED80 Carbon Fiber Edition Telescope
More Details
$1149.00 $849.99

Free Shipping

Explore Scientific 80mm FCD100
More Details
$999.99

Free Shipping

Explore Scientific AR102 102mm Achromatic Refractor Telescope
More Details
$499.99 $399.99
Explore Scientific ED102 Essential Edition Telescope
More Details
$1249.99 $1029.99

Free Shipping

Explore Scientific ED102 Carbon Fiber Edition Telescope
More Details
$1729.99 $1274.99

Free Shipping

Explore Scientific 102mm FCD100 Apo Refractor
More Details
$1499.99

Free Shipping

Explore Scientific AR127 127mm Achromatic Refractor Telescope
More Details
$599.99

Free Shipping

Explore Scientific ED127 Essential Edition Telescope
More Details
$1899.00 $1549.99

Free Shipping

Explore Scientific ED127 Carbon Fiber Edition Telescope
More Details
$2499.99 $1848.99

Free Shipping

Explore Scientific 127mm FCD100 Apo Triplet
More Details
$1999.99

Free Shipping

Explore Scientific AR152 152mm Achromatic Refractor Telescope
More Details
$799.99

Free Shipping

Explore Scientific 152mm Carbon Fiber Apochromatic Refractor w/Starlight 3" Focuser
More Details
$5999.00 $4924.99

Free Shipping

Explore Scientific 115mm F/5.5 FPL-53 Triplet ED APO Refractor
More Details
$2999.99

Free Shipping

115mm F/5.5 FPL-53 Triplet with 3-inch Feather Touch Focuser
More Details
$3874.99

Free Shipping

Explore Scientific 140mm F/6.7 FPL-53 Triplet ED APO Refractor
More Details
$4999.99

Free Shipping

140mm F/67 FPL-53 Triplet with 3-inch Feather Touch Focuser
More Details
$5874.99

Free Shipping

Meade Infinity 90mm Altazimuth Refractor
More Details
$189.00

Free Shipping

Meade Infinity 102mm Altazimuth Refractor
More Details
$249.95 $229.95
Orion Sirius ED80 EQ-G Computerized GoTo Refractor Telescope
More Details
$1499.00
Orion ED80T CF Triplet Apochromatic Refractor Telescope
More Details
$949.00

Free Shipping

Orion Astroview 120ST EQ Telescope
More Details
$599.00
Sky-Watcher Esprit 80 ED APO Refractor
More Details
$1649.00

Free Shipping

Sky-Watcher Esprit 100 ED APO Refractor
More Details
$2499.00

Free Shipping

Sky-Watcher Esprit 120 ED APO Refractor
More Details
$3199.00

Free Shipping

Sky-Watcher Esprit 150 ED APO Refractor
More Details
$6399.00

Free Shipping

Stellarvue SV70T
More Details
$899.00
Stellarvue SV80-Access
More Details
$699.00

Free Shipping

Stellarvue SV102-Access
More Details
$1095.00

Free Shipping

Stellarvue SV102-Access with Diagonal
More Details
$1234.00

Free Shipping

Stellarvue SV80ST-25SV Triplet Refractor Telescope
More Details
$1295.00

Free Shipping

Stellarvue SVQ100 Astrograph
More Details
$2995.00

Free Shipping

Stellarvue SVR102T-25SV APO Triplet Refractor Telescope
More Details
$2295.00

Free Shipping

Stellarvue SV125 Access
More Details
$1995.00

Free Shipping

Stellarvue SVA130T-25SV
More Details
$3295.00

Free Shipping

Refractor Telescopes & Apochromatic Refractor Telescopes

Refractors are the optical design that most people associate with a telescope. Like any other telescope, their primary function is to gather as much light as possible, rendering distant objects brighter and easier to see when magnified. Refractors do this by using an objective lens group at the front of the telescope, which uses two or more pieces of glass to focus light at the viewing end of the telescope. The bigger this objective lens, the more light the telescope can gather, and the more the viewer can see. Refractors equipped with a 90 degree star diagonal produce images that are upright but right-left reversed, making them useful for both terrestrial viewing and stargazing purposes.

There are three primary types of refractors: achromats, ED Achromats, and apochromats. Functionally they differ in the level of correction of chromatic aberration, or false color. Chromatic aberration is most commonly seen as a violet halo around bright objects, but there are other more subtle visual impacts. False color occurs because glass lenses alter the path of light in proportion to its wavelength; red and blue light exit a lens at different angle. All refractos have at least two lenses, and some have three or more, in order to get different wavelengths to come into focus in the same plane. Refractors are categorized according to their construction, which also corresponds with the level of color correction:

  • Achromatic: An achromatic lens uses two-lenses in the objective, called a doublet, to correct for chromatic aberration. The two lenses are designed to focus both red and blue light at the same point, while green is focused to a slightly different point. Since the human eye reacts more to green light in the dark, the green light will appear brighter and more in focus compared to blue and red light. The result is a slight chromatic aberration, which often appears as purple halos around bright objects. Achromatic refractors are typically sold as inexpensive beginner telescopes.

  • ED Achromatic: ED achromats utilize exotic high refractive index glasses to minimize chromatic aberration in doublet designs.  Well executed examples of this type are often represented as apochromatic telescopes and can be nearly indistinguishable visually from the more expesive apochromatic refractors.  Some false color may appear around the brightest stars in photographs, but it may not be objectionable to most users.

  • Apochromatic: Apochromatic means virtually free of false color. Achromatic refractors often use three lenses in an objective, called a triplet, to correct chromatic aberration completely bringing red, blue and green light all to the same point of focus. Other more exotic examples use four or more lenses in multiple groups. The result is an image devoid of halos, producing pinpoint stars against a black background. This means apochromatic refractors are capable of higher magnifications and produce excellent images for astrophotography. The primary limiting factor for an apochromatic refractor, however, is its relatively higher cost compared to an achromatic or ED achromatic model.

Refractors have a wider variation in quality level than any other type of telescope, and the better ones are certainly the most expensive in dollars per unit aperture. That’s why choosing the right type of refractor for your needs is so essential — and Skies Unlimited can help. We’re committed to providing you with the type of refractor that will fit your needs exactly. We offer refractor telescopes for sale from all major suppliers, including Takahashi, TeleVue, Sky-Watcher, Stellarvue, Explore Scientific, and more.