Kson Olympus AS102 ED APO refractor released from Astro Dog

Astro Dog has introduced the Kson "Olympus" AS102, a classic air-spaced crown and flint doublet achromat refractor, featuring a 102mm aperture and an impressive f/12 focal length (extendable to f/15 with an aperture cap).

Kson Olympus AS102 ED APO (102mm/1200mm f/12) refractor (FPL51/Lanthanum Doublet) lands from Astro Dog

This refractor is meticulously designed for the pure pleasure of visual planetary, lunar, double star, and some deep-sky object (DSO) viewing. As one of the longest focal-length modern achromats currently available, it offers extraordinary contrast and clarity, making it ideal for those who want to explore celestial wonders up close. Remarkably, it provides these features without the hefty ‘ED’ pricetag.

• The Kson Olympus AS102 ED APO from Astro Dog is a 102mm (4 inch) f/12 refractor with unique features and inclusions.
• Designed for visual planetary, lunar, double star, and DSO viewing, this long focal length refractor combines a modern optical design with traditional high-quality engineering.
• The Olympus range includes two versions: an achromat and this APO model.
   

Kson Olympus AS102 APO specifications

• FPL51 and Lathanum Doublet (Design and Optical Quality APO)
• Objective Lens Diameter of 102mm, 1200mm focal length, f/12
• The primary lens is hand-figured by Kson and features excellent spherical correction and smooth surfaces.
• Fully multicoated with edge blackened lenses. Every lens cell is factory checked for collimation and artificial star tested for quality assurance.
• The telescope tube features ray-traced baffles to eliminate stray light and also has the inner surfaces painted matt black for superior contrast.
• Kson “Built for Life” Design – No plastic bits.  User serviceable collimatable lens cell makes it a real lifetime instrument, with no need to ever return it to factory should it ever slip out of collimation.
• Additional 2″ draw tube extension allows the scope to be used in a large variety of optical configurations and eyepieces and allows for the use of binoviewers with 110-140mm light path without an optical corrector allowing a substantially wider native view to be enjoyed.
• Sturdy 2″ CG dual-speed crayford style focuser with compression ring and Kson’s unique tri lock screw system – Accepts 2″ eyepieces, DSLR’s and 2″ Accessories
• Extra long 330mm fully retractable dew shield (also painted matt black inside) allowing easy mobility and transport and providing dew protection
• Metal quick release bracket on scope
• The refractor ships with Kson’s own rube rings and extra long 300mm dovetail bar for additional stability on your mount
• Limiting magnitude 12.74
• Color: Pearl White, Red Rings

Bonus Kson Ortho II Volcano 4.5mm (carbon fibre) eyepiece included:

• Included is a Premium Kson Ortho II Volcano 4.5mm (carbon fiber) Eyepiece for enhanced viewing.
• 80mm aperture cap to convert  to f/15 and reduce moon glare.
• Handy Nylon Travel Bag included (140x22x22cm) (valued at $99.95)
   

At the time of purchase, you may purchase the "Kson Starter Pack L" at ($149.95) which adds the following:

• Red Adjustable Kson 8×50 reticled finder
• 10mm 3 Element Kson Eyepiece
• 25mm 3 Element Kson Eyepiece
• 1.25″ Mirror Diagonal

Kson Olympus is compatible with various mounts

The Kson Olympus can be used with a variety of mounts. For visual use, it is recommended to pair it with a Saxon EQ3 with a steel tripod and pier extension (adequate), a Kson EQ4 with a pier extension (very good, and includes extra-long slow-motion controls), or an HEQ5 or EQ6 Pro with the relevant pier for those interested in automation.

What makes this particularly suitable for binoviewers?

Binoviewers are devices that resemble binoculars but attach to telescopes, allowing for stereo viewing with both eyes. The Kson Olympus was designed to be highly compatible with binoviewers, often eliminating the need for an optical corrector or Barlow lens. This compatibility allows for improved viewing quality, a greater range of compatible eyepieces, and a wider field of view.

For those interested in binoviewing, the Celestron #93691 Stereo Binocular Viewer paired with lightweight eyepieces is recommended as a starting point.

What’s the difference between the Kson Olympus ED APO and the TS-Optics ED?

Both are highly recommended. A few differences: the TS-Optics is f/11, while the Kson is f/12, pushing it deeper into APO territory. Both use FPL-51. Kson specifies that they use Lanthanum as part of the second element, while TS-Optics does not specify (mentioning "additional special glass"). The TS-Optics ED has a shorter (1.5x) dew shield, while Kson's (3x) is designed for extended observing. The Kson features a handle, while the TS-Optics does not. The TS-Optics has a weight of 4.6kg, while Kson's is lighter (more details to come). The TS-Optics comes with a 2″ to 1.25″ adapter, dust caps, finder shoe, CNC tube rings, and a dovetail bar. Kson includes a 2″ to 1.25″ adapter, dust caps, finder shoe, CNC tube rings, and a dovetail bar, plus a handy nylon bag, a 1.25″ diagonal, and an ortho eyepiece. The final configuration may include an 80mm aperture cap to reduce glare and increase the f/ratio to f/15 for particularly bright targets (Lunar/Jupiter). Aesthetics aside, the Kson is a single piece, while the TS-Optics tube unscrews and is a two-piece system. The Kson uses a 2″ extension tube when extra focal length is needed.

The widely quoted 1.5x of diameter is not actually recommended; rather, it is a minimum to stop stray light and have some effect on dew. Sidgwick recommends 2.5 to 3x the diameter. Kson is the only manufacturer to meet that standard, making it able to perform with less dew impairment even without dew straps.

What’s the difference between the Kson Olympus ED APO and the TS-Optics SD?

The SD uses FPL53 (instead of FPL51) and "an additional special glass," but is otherwise comparable to the TS-Optics ED.