Explore Scientific AR127 127mm f/6.5 Doublet Refractor Telescope

Faint galaxies and globular clusters reward aperture, and stepping from a 4-inch to a 5-inch refractor gathers (127 ÷ 102)², about 1.55 times, the light. The Explore Scientific AR127 (item DAR127065-02) is that step in Explore Scientific's AR line: a 127 mm f/6.5 air-spaced achromatic doublet, built to stand up to public star parties and educational outreach, with an 8x50 finder, a 99% reflective 2-inch diagonal and a two-speed 2-inch Crayford focuser included. The AR127's interferometric optical data is available from Explore Scientific on request after 120 days of ownership.

Key Features

• Optics. A crown glass lens and a flint glass lens, separated by an air space to minimize chromatic aberration, fully multi-coated, in a three-point collimation cell. Explore Scientific collimates it in quality control before shipping; some AR127s take a #3 Phillips screwdriver for the collimation screws.
• Focal length. 826 mm at f/6.5, for targets from the Moon's craters and Saturn's rings to the face-on Pinwheel Galaxy.
• Focuser. A two-speed 2-inch Crayford with a compression ring, with stacked coarse and fine dials and a locking screw.
• Diagonal. A one-piece 2-inch diagonal with 99% reflective dielectric coatings, taking 2-inch eyepieces or 1.25-inch ones through its adapter.
• Finder. A straight-through 8x50 with a crosshair on the Explore Scientific Hybrid Finder Scope Base, with a quick-release bracket.
• Rings. A felt-lined cradle ring with a carry handle on a Vixen-style dovetail, which fits an alt-azimuth or equatorial mount.

Who It's For

• Deep-sky observers. For this focal length, Explore Scientific recommends the 52° Series 30mm (28x), 62° Series 14mm (59x) and 62° Series 5.5mm (150x) eyepieces.
• Star parties and outreach, the use Explore Scientific designed the AR series for.
• Observers choosing a size. The AR102 is the 102 mm version at 10.4 lb, against the AR127's 15 lb.
• Observers deciding on glass. An achromatic doublet leaves some color around the brightest targets. The ED127 Essential puts HOYA FCD1 glass in a 127 mm triplet at f/7.5 and costs more.

Accessories & Compatibility

• Mounts. The EXOS2-GT carries a 28 lb instrument payload for astrophotography. The Twilight I alt-azimuth mount takes telescopes up to 18 lb with a Vixen-style dovetail; at 15 lb the AR127 is within that rating.
• Imaging. Explore Scientific's Field Flattener f/5 to f/7 is compatible with the AR127 (DAR127065-02). It is for photographic use only and needs 55 mm (±2 mm) of spacing to the camera sensor.