Askar AP 203/1421 OTA

Askar AP 203/1421 OTA is one of the largest apochromatic refractors currently available. With an aperture of 203 mm and a focal length of 1421 mm, this model belongs to the absolute top class for observatories and high-end astrophotography. The air-gap triplet lens, constructed of ED (extra-low dispersion) glass, almost completely corrects chromatic aberration and delivers images with extreme contrast, high resolution and natural color reproduction.

Despite its size, the construction is practically designed. The CNC-machined tube features integrated extensions that allow switching between photography and visual observation, including the use of prisms and bino viewers. The solid construction and high-quality workmanship ensure stability and durability for long-term use in a fixed observatory.

The 3.5″ rack-and-pinion focuser with 1:10 reduction offers a 100mm setting range and is compatible with most electronic focus motors. The anti-reflection coating and graduated scale allow you to focus extremely accurately, even with heavy cameras and filter wheels. The 360° rotator with scale and sturdy locking screw makes it easy to precisely adjust your image frame.

The telescope comes with sturdy tube rings, a Losmandy swallowtail and a transport case. With a tube weight of 23.5 kg, a heavy-duty mount such as the Sky-Watcher EQ8-R (Pro or RH) is recommended for full performance.

Application
The Askar AP 203/1421 OTA is intended for advanced astrophotographers and professional observers who demand uncompromising performance. It is suitable for:

• Astrophotography of deep-sky objects such as nebulae, galaxies and globular clusters at maximum resolution.
• Planetary observations with extreme contrast and color neutrality.
• Fixed setups in observatories where stability and image quality are critical.

Specifications

• Optical design: refractor (apochromatic, triplet with air gap)
• Aperture: 203 mm
• Focal length: 1421 mm
• Aperture ratio: f/7
• Resolution: 0.68″
• Boundary magnitude: 13.3
• Max. useful magnification: 406x
• Light output: 840x relative to naked eye
• Tube weight: 23.5 kg
• Focuser: 3.5″ rack & pinion, 1:10 reduction, 100 mm range, rotatable 360°
• Free opening of focuser: 89 mm
• Ocular connection: 2″ with adapter to 1.25″
• Included: Tube rings, Losmandy swallowtail, accessory shoe (Vixen/Sky-Watcher), transport case, dew cap, eyepiece adapter 2″/1.25″
• Corrector: Not included (optionally available)