Product Description
Dual-speed 2.5" Hexagonal focuser with 10:1 ratio fine focusing
Mounting rings with dovetail for use on a Vixen-style altazimuth or German equatorial mount
Finderscope base installed on OTA
Extended product lifetime warranty
With a 5" (127mm) aperture, this Explore Scientific Classic White ES127 FCD100 ED triplet refractor gathers 55% more light (with nearly 25% higher resolution) than the more common size 102mm (4") doublet and triplet refractors that often cost nearly as much as the ES127.
The Explore Scientific ES127 uses the premium Hoya FCD100 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 scope's relatively large aperture, and even at very high magnifications.
The Explore Scientific ES127 is a natural on an equatorial mount as the heart of your primary observing system. In addition, it's an excellent astrograph for serious wide field imaging, as well as crisp solar system imaging. Considering its surprisingly reasonable price for a 5" apochromatic triplet and in view of the great optical performance that comes as standard equipment, the 5" Explore Scientific ES127 FCD100 is a terrific buy!
Features of this Telescope . . .
ED triplet refractor optics: 127mm (5") aperture, 952mm focal length, f/7.5 focal ratio three-lens air-spaced optical system. The optics use a center lens element of Hoya FCD100 (Dense Fluor Crown) glass, the Hoya equivalent of FPL-53 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, particularly those with apertures in the ES127 class. Relying on technological innovation, Explore Scientific has successfully launched the mass production of high-performance optical glass at the apex of the FCD family. Combining it with optical glass of high refractive index allows them to achieve unprecedented advanced chromatic aberration correction. Hoya FCD100 is considered the best glass ever produced by Hoya.
Fully multicoated optics: The ES127 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: The aluminum tube body has contrast-enhancing internal light baffles and a specially darkened tube interior to provide dark sky backgrounds and high 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. A slip-on metal dust cap is standard.
Dual speed 2.5" Hexagonal focuser: The rotating 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 DSLR 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. Lock knobs let you adjust the tension on the drawtube to accommodate varying eyepiece/photo accessory loads, as well as firmly lock in a photographic focus. The focuser terminates in a non-marring 2" compression ring accessory holder. Two 2" draw tube extensions are included to let adjust the back focus when using a diagonal and eyepieces versus a camera.
Mounting rings and dovetail: The ES127 has dual split mounting rings with a dovetail plate that fits the Vixen-style dovetail slot on the head of many of the most popular medium capacity German equatorial mounts. Such mounts include Celestron and iOptron go-to mounts, among others. A spacer/stabilizing bar on the top of the rings provides a carrying handle that makes it easy to transport the optical tube and install it on your equatorial mount. There is a mounting shoe for an optional finderscope installed on the body of the scope.
Extended 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 Life of The Product limited warranty when its warranty card is registered with Explore Scientific within 60 days of purchase. Full details on this unique transferable lifetime warranty.
Tech Details
Aperture | 5" |
---|---|
Binary and Star Cluster Observation | Very Good |
Focal Length | 952mm |
Focal Ratio | f/7.5 |
Galaxy and Nebula Observation | Good |
Highest Useful Magnification | 271x |
Lunar Observation | Great |
Weight | 22 lbs. |
Planetary Observation | Very Good |
Resolution | 0.91 arc seconds |
Telescope Type | Refractor |
Visual Limiting Magnitude | 13 |
Warranty | 1 year, extendable to lifetime |
Reviews
I presume ES still has the Feathertouch focuser option and I highly recommend going that route from the get-go. The OEM focuser is "ok", and performs adequately, but it's not a Feathertouch. I don't know about the newer OTAs, but its impossible to remove the stock focuser from mine - must be glued on! Wayne at Starlight says he can remove it but I'm of the "if it ain't broke, don't fix it" mentality, and as I said the focuser performs decently. Other than that, great little refractor at a good price. (Posted on 12/4/2019)
One small thing that annoyed me is that the scope comes with two adapters for its 2.5" drawtube, but neither is the adapter you need to use with the Bresser/ES 3" 0.7x reducer. I bought this scope for the 2017 total solar eclipse, so I bit the bullet and purchased the 0.7x reducer to get a wider field, but I have subsequently purchase the 1.0x TS-Flat2 2" flattener and a Williams-Optics 0.8x P-Flat6a-III flattener/reducer. Watch out, you will need an adapter at the time of this writing in order to use a WD-Dig2a nose piece from WilliamOptics (or less expensive equivalents from eBay or AliExpress) to use the P-Flat6a-III. RafCamera on eBay made the the adapter for me. WO tells me that they will make that adapter soon. (Posted on 9/9/2019)
Supplied Accessories
- Dual tube rings with Vixen-style dovetail
- 2.5" dual speed Hexagonal focuser
- Retractable dew shield
- Dust covers
- Finderscope base