| This Explore Scientific ES80 refractor has:
• 80mm f/6 air-spaced triplet apochromatic optics using a Hoya FPL51-equivalent ED element
• dual-speed 2” Crayford focuser with 10:1 ratio fine focusing
• 2” dielectric star diagonal with 2” and 1.25” brass compression ring eyepiece holders
• 8 x 50mm illuminated erect-image/right-reading finderscope
• dovetail shoe for installing on a Vixen-style altazimuth or German equatorial mount
• lifetime transferrable limited warranty
The Explore Scientific ES80 uses a premium Hoya ED glass element and state-of-the-art optical multicoatings in its apochromatic air-spaced ED triplet optics. The result is images that are essentially free of the annoying halo of unfocused violet light (chromatic aberration) that mars the view of bright stars and solar system objects in lesser scopes, despite the fast focal ratio of the ES80, and even at very high magnifications.
The 80mm Explore Scientific triplet optics are even more appealing when you consider that this Explore Scientific apo is loaded with features other manufacturers charge extra for (or don’t even have available) – such as an illuminated 8 x 50mm finderscope with erect right-reading images, a 2” dielectric star diagonal with 1.25” and 2” compression ring accessory holders, and a flight-ready carrying case. Even better, the ES80 is priced hundreds of dollars less than competitive 80mm triplet scopes – and even less than many comparably-equipped doublet systems!
The Explore Scientific ES80 is a natural as a lightweight grab-and-go scope for spur-of-the-moment backyard astronomy. It also makes a top-notch travel scope to take across town or around the world. In addition, it’s a nifty fast focal ratio astrograph to piggyback on a larger scope for serious wide field imaging, or you can even use it on a big altazimuth or equatorial mount as the heart of your observing system. Considering its surprisingly low price for an apochromatic triplet, adding in the extra features you get at no extra cost, and in view of the great optical performance that comes as standard equipment, the 80mm Explore Scientific ES80 is a terrific buy!
Features of this telescope . . . - Air-spaced ED apochromatic triplet refractor optics: 80mm (3.1”) aperture, 480mm focal length, f/6 focal ratio three-lens air-spaced optical system. The optics use a center lens element of Hoya FCD1 (Dense Fluor Crown) glass, the Hoya equivalent of FPL-51 ED (Extra-low Dispersion) glass. This ED element produces superior sharpness and color correction by minimizing the chromatic aberration, the “false” color fringing seen around bright objects when light rays pass through standard crown-and-flint doublet objectives. The result is to reduce spurious color halos and fringing to vanishingly low levels.
- Fully multicoated optics: The ES80 triplet objective lens has EMD™ (Enhanced Multilayer Deposition) antireflection multicoatings on all air-to-glass surfaces for high light transmission, minimal light scatter, and excellent contrast.
- Internal light baffles: Contrast-enhancing internal light baffles and a specially darkened tube interior provide dark sky backgrounds and high terrestrial contrast.
- Collimatable optics: One of the bonuses of owning a refractor is that, compared to standard reflector telescopes, they almost never require realigning of the optics (collimation). However, any air-spaced refractor telescope may require optical recentering if the lens elements are knocked out of alignment by a heavy blow during shipping or use. Removing the dew shield will give you access to the lens centering screws in the sides of the lens cell, which you can then adjust yourself by referring to the supplied instructions. You can also send your scope to Explore Scientific’s Service Center for precision alignment. A standard service charge applies for factory realignment.
- Dew shield: The supplied retractable dew shield slows the formation of dew on the lens in cold weather to extend your undisturbed observing time. It also improves the contrast, similar to the effect of the lens shade on a camera lens, when observing during the day or when there is excessive ambient light at night, such as a neighbor’s backyard security light. The optical tube measures a compact 18.5” long, including the dew shield. A slip-on metal dust cap is standard.
- Dual speed 2” Crayford-style focuser: The precision-made no-backlash focuser has dual-speed focusing. There are two coarse focusing knobs. The right knob also has a smaller concentric knob with a 10:1 reduction gear microfine focusing ratio. This provides exceptionally precise image control during high magnification visual observing and critical 35mm or CCD imaging. The large focus knobs have ribbed gripping surfaces so they are easy to operate, even while wearing gloves or mittens in cold weather. The focuser drawtube has a scale marked in centimeters and 1mm increments. This lets you note individual focuser positions for easy return to the correct focus when switching between visual use and photography. Two knobs underneath the focuser lets you adjust the tension on the drawtube to accommodate varying eyepiece/photo accessory loads, as well as firmly lock in a photographic focus.
- 2” dielectric star diagonal and compression ring eyepiece holders: The supplied standard equipment 2” mirror star diagonal of the ES80 slips into the focuser drawtube’s 2” eyepiece/accessory holder. The 2” diagonal has 99% reflectivity dielectric mirror coatings for high light transmission. The star diagonal uses a non-marring soft brass compression ring to hold 2” eyepieces in place. The compression ring won’t scratch the barrel of your 2” eyepieces as an ordinary thumbscrew can. A supplied 1.25” accessory adapter slips into the 2” diagonal to let you use 1.25” eyepieces in the 2” diagonal. The 1.25” accessory adapter can also be inserted into the 2” accessory holder on the focuser drawtube to let you use a 1.25” image erecting diagonal, or 1.25” photographic accessories. Like the 2” eyepiece holder on the diagonal, the 1.25” adapter also uses a non-marring soft brass compression ring to hold 1.25” star diagonals and accessories in place.
- Mounting dovetail: For serious astronomy and astrophotography, the ES80 has an L-shaped dovetail mounting foot that is shaped to fit directly into the Vixen-style dovetail slot on the head of many of the most popular light to medium capacity altazimuth and German equatorial mounts. Such mounts include the Astro-Tech Voyager altazimuth, the Celestron Advanced Series go-to equatorials, the Meade LXD-75 go-to equatorial, and the Vixen Sphinx and Great Polaris Deluxe equatorial mounts and Porta altazimuth mount, among others. In addition, the dovetail has both 1/4"-20 and 3/8” holes that allow you to mount the 7.5 pound scope (including diagonal) directly onto any good photo tripod for casual astronomy or daytime terrestrial observing. A knob on the body of the scope allows you to rotate the tube assembly to line up a camera in either a landscape or portrait orientation (or any orientation in between), then temporarily lock the focuser in that position.
- Finderscope: The Explore Scientific ES80 comes with an 8 x 50mm straight-through finderscope with a wide 6° field of view. It is fully-multicoated to insure maximum brightness and contrast. A precision-polished roof prism in the finder produces images that are right-side-up and left-to-right correct. In other words, the sky is not upside-down and backwards as it is in most straight-through finders. You can independently focus both the finderscope objective to make the stars pinpoint sharp and sharply focus the crosshairs in the finder’s illuminated reticle eyepiece. The unique illuminated reticle has crosshairs with an open circle in the center (so you don't mask the object you are centering with the crosshairs). There are scale markings on the crosshairs for 1.5°, 3°, and 4.5° fields (the edge of the field of view is the 6° boundary).
- Five year warranty: This individually serial numbered Explore Scientific product is backed by a limited one year warranty, which will be extended to an Explore Scientific STAR lifetime transferrable limited warranty when the product warranty card is registered with Explore Scientific within 60 days of purchase. For full details on this unique transferrable lifetime warranty, click on this link.
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