Sharpstar Apochromatic refractor AP 100/550 Z4 OTA (82798)

The Sharpstar AP 100/550 Z4 OTA is a professional-grade apochromatic refractor designed for advanced astrophotographers seeking high optical performance and ease of use. Its unique sextuplet (six-element) Petzval design, featuring two extra-low dispersion (ED) glass elements, delivers a flat, wide field with excellent color correction and no need for a separate field flattener or complicated backfocus calculations. The telescope is optimized for APS-C sensor cameras, providing a 36 mm corrected image circle, and is well-suited for deep-sky, planetary, and widefield imaging. With a robust construction, smooth dual-speed focuser, and a range of included adapters, the Z4 is ready for demanding imaging sessions straight out of the box.

The Sharpstar Z4 is ideal for astrophotographers who want a high-quality, flat-field imaging telescope that is easy to set up and use, with no need for additional flatteners or reducers. Its robust mechanics and high-end optics make it a top choice for capturing sharp, color-accurate images across a wide field.

Optical System and Performance

• Type: Refractor, apochromatic sextuplet (3+3 Petzval design)

• Aperture: 100 mm

• Focal length: 550 mm

• Focal ratio: f/5.5

• Resolving power: 1.38 arcseconds

• Limiting magnitude: 11.8

• Light gathering capacity: 200x the naked eye

• Maximum useful magnification: 200x

• Field diameter: 36 mm (APS-C image circle)

• Lens design: Triplet front group, triplet rear group, two ED elements for superior chromatic correction

Focuser and Connections

• Focuser: Large 3.4" rack-and-pinion with 1:10 fine focusing and 360° rotation for precise camera framing

• Eyepiece connection: 2"

• Camera-side threads: M86, M68, M54, M48 (adapters included)

• Backfocus: 55 mm from M48 thread

• Free aperture: 86 mm

• Filter thread: Yes (2" filters compatible)

Tube and Mounting

• Tube weight: 4.3 kg (including tube rings and dovetail)

• Carrying length: 482 mm

• Tube diameter: 112 mm

• Dew shield diameter: 125 mm

• Tube material: CNC-machined aluminum

• Mounting: Vixen-style dovetail plate (300 mm length), compatible with most equatorial mounts

• Carrying handle: Included, with integrated finder base (Vixen/Skywatcher level)

• Tube clamps: Included

• Transport case: Included

Included Accessories

• Clamshell tube ring

• 300 mm Vixen-style dovetail bar

• Multifunctional carrying handle

• Adapter rings: M86x1 to M68x1, M68x1 to M54x0.75, M54x0.75 to M54x0.75, M54x0.75 to M48x0.75 (with 2" filter thread)

• Manual

Applications

• Astrophotography: Excellent, especially with APS-C cameras

• Moon and planets: Suitable

• Nature observation: Possible with appropriate accessories

• Nebulae and galaxies: Excellent

• Solar observation: Only with a suitable solar filter (not included)

• Recommended for advanced users; not intended for beginners or observatory installations