Scientific 5” refractor/altazimuth mount package has:
- big 5” aperture
fully multicoated AR127 achromatic doublet refractor optics
objective lens cell for fine-tuning the images
- big 8 x 50mm
- 2” dielectric
star diagonal with 1.25” eyepiece adapter
- tube rings with
carry handle and Vixen-style dovetail plate
- Twilight 1
altazimuth mount with slow motion controls
This Explore Scientific AR127 refractor has a 127mm (5”)
diameter multicoated doublet objective lens (825mm focal length f/6.5). It has
diffraction limited optics that are sharp and well suited to serious deep space
observing of binary stars, star clusters, and the brighter nebulas and galaxies,
in addition to excellent high contrast planetary and lunar images. The objective
lens cell is fully collimatable, using push/pull collimation screws, so you can
optimize your image quality.
The 5” Explore Scientific AR127 doublet refractor is a great
grab-and-go scope for quick looks at the sky when mounted on the lightweight and
stable Twilight 1 altazimuth mount. It is also good enough optically to be the
heart of a reasonably-priced serious observing and imaging system when mounted
on one of the many equatorial mounts from Celestron, Meade, iOptron, and
Some chromatic aberration is visible on stars and objects of
2nd or 3rd magnitude and brighter, as you would expect in an achromatic
refractor with such a fast focal ratio. However, the spurious color is well
controlled and not unreasonable, thanks to careful optical design, and has
little effect on deep space observing. Most observers feel the relatively
limited amount of chromatic aberration visible is a small price to pay for the
scope’s many other virtues of portability, sharpness, contrast, and optical
This Package . . .
refractor optics: 5” (127mm) aperture, 825mm focal length, f/6.5
air-spaced crown and flint glass doublet lens. Tube diameter is 5.13” (130.4mm)
and the tube length with dewshield installed is 34” (864mm). Scope weight is 15
pounds (6.82 kg).
lens cell: The 5” Explore Scientific lens is precision collimated at
the factory to give optimum performance. Although you may never need to adjust
optical alignment, the ES127D allows for collimating the lens set should the
telescope ever require it due to a fall or very rough handling.
optics: Fully coated on all surfaces with multiple layers of
antireflection materials for high light transmission and good contrast.
- Internal light
baffles: Multiple internal knife-edge baffles in the optical tube mask
and deflect unwanted stray light for improved contrast.
shield: The removable dew shield slows the formation of dew on the lens
in cold weather to extend your undisturbed observing time. It also improves
visual and photographic contrast by shielding the lens from off-axis ambient
light (the neighbor’s yard light, moonlight, etc.)
covers: Front and rear dust covers are provided.
Crayford-style focuser: 2” focuser, with adjustable tension and lock
knobs. The 2” eyepiece holder uses a non-marring brass compression ring to hold
the supplied 2” star diagonal in place without scratching the diagonal barrel.
The precision-made 2" focuser has dual-speed focusing. There are two coarse
focusing knobs. The right knob also has a smaller concentric knob with 10:1
ratio reduction gear microfine focusing. This provides exceptionally precise
image control during high power visual observing or critical DSLR or CCD
imaging. The focus knobs have ribbed gripping surfaces so they are easy to
operate, even while wearing gloves or mittens in cold weather.
- Dielectric star
diagonal: 90° viewing angle first surface mirror 2” star diagonal with
1.25” eyepiece adapter. The diagonal uses durable 99% reflectivity for maximum
light transmission and long life.
- Finderscope: 8 x 50mm straight-through achromatic design,
in a dual-ring six-point adjustment bracket with a quick release mounting shoe.
Focuses by loosening the trim ring behind the objective lens cell, screwing the
lens cell in or out to focus, and tightening the trim ring to lock in the
- Dovetail tube
mount: The optical tube comes with two split and hinged tube rings for
installing the optical tube on your mount. The rings are connected to an
industry-standard Vixen-style dovetail mounting plate that slips into the
dovetail groove on the supplied Explore Scientific Twilight 1 mount, as well as
equatorial mounts from Celestron, iOptron, and others. A carrying handle is
conveniently fitted to the top of the tube rings.
- Twilight 1
altazimuth mount: The supplied Twilight I light-to-medium-duty
altazimuth mount weighs only 17.6 pounds (8 kg). It has a payload capacity is 18
pounds (8.2 kg), so it can handle the 15 pound 127mm doublet optical tube with
ease. It has worm gear slow motion controls on both axes to let you smoothly
follow the motion of the Moon, planets, and deep space objects across the
heavens. The cast aluminum single arm and head can tilt forward or back at a 45°
angle, as well as point straight up, depending on your observing preferences.
The chrome-plated steel tripod of the Explore Scientific Twilight I mount has
adjustable height legs. With the legs fully retracted, the tripod is 38.5". With
the legs fully extended, the tripod is 55.5" high at highest point.
lifetime warranty: This individually serial numbered Explore Scientific
telescope is backed by a limited one year warranty, which will be extended to an
Explore Scientific transferable product lifetime limited warranty when its
warranty card is registered with Explore Scientific within 60 days of purchase.
|Optical Design||Refractor - Achromatic|
|Mount Type||None - Optical Tube Only|
|Telescope Focal Length||988mm|
|Telescope Focal Ratio||f/6.5|
|Limiting Stellar Magnitude||13|
|Optical Coatings||Explore EMD|
|Tube Color or Finish||Gloss White|
|Optical Tube Outer Diameter||130mm|
|Length of Optical Tube||863mm|
|Total Telescope Weight||15.6 lbs.|
|Dew Shield Included?||Yes|
|OTA Mount Type||Dual Rings|
|Finder Included||8 x 50 Optical Finder|
|Diagonal Included?||Yes - 2" Star Diagonal|
|Tripod Type Included||None, Sold Separately|