Askar Refractor 71F Flat Field

Askar Refractor 71F Flat Field

Description

The Askar 71F is an OTA with a 71 mm aperture, 490 mm focal length and a native f/6.9 focal ratio. Its quadruplet air-spaced APO design includes one ED glass element that effectively reduces chromatic aberration while supporting a 44 mm full-frame image circle with excellent edge star performance.
Its self-flattened design eliminates the need for an additional flattener and back-focus calculations: once imaging accessories are connected and focus is achieved, the system is immediately ready for astrophotography.
The OTA weighs only 2.5 kg (3 kg with rings and dovetail), making it highly portable and easy to use.
For visual observing, the Askar 71F includes three standard accessories: an 8 mm eyepiece, a 20 mm eyepiece and a 1.25" 45° erecting prism. The 8 mm eyepiece provides 60x magnification and the 20 mm provides 25x, suitable for viewing landscapes and wildlife. Both eyepieces feature 1.25" barrels and rubberized eye guards. The erecting prism delivers correctly oriented images.
A photographic extension tube is supplied with M48×0.75 and M54×0.75 adapters, plus an internal 2" filter thread for convenient camera connection. It supports DSLR cameras and astronomy cameras for quick on-site imaging.
The retractable dew shield shortens the total length and increases portability. The internal matte coating reduces stray light. The blue-and-white CNC-machined tube reflects Askar’s high manufacturing standards.
The handle includes a finder slot, while two additional finder bases on the focuser provide more mounting options without disassembly.
The 2.4-inch rack-and-pinion dual-speed focuser offers 1:10 fine adjustment and a 360° scale rotator for accurate framing.
The 230 mm Vixen-style dovetail plate includes both 1/4" and 3/8" threads for direct tripod mounting.
Combining affordability, optical quality and versatility, the Askar 71F is an excellent companion for travel, visual observing and astrophotography.

Technical specifications

• Aperture size: 71 mm

• Focal length: 490 mm

• Focal ratio: f/6.9

• Objective lens: Quadruplet air-spaced APO with one ED glass

• Image circle: 44 mm

• Maximum accessory connection (focuser retracted):

  • Imaging: 82.5 mm (M48×0.75 base), 100.5 mm (M54×0.75 base)

  • Visual: 111 mm (1.25"), 121 mm (2")

• Minimum accessory connection (focuser extended):

  • Imaging: 32.5 mm (M48×0.75 base), 50.5 mm (M54×0.75 base)

  • Visual: 61 mm (1.25"), 71 mm (2")

• Total length:

  • 372.5 mm (dew shield retracted with 1.25" adapter)

  • 430.9 mm (dew shield extended with 1.25" adapter)

  • 415 mm (dew shield retracted with photographic adapter)

  • 473.4 mm (dew shield extended with photographic adapter)

• Focuser travel length: 50 mm

• Net weight: 2.5 kg

• Gross weight (with rings and dovetail plate): 3 kg

• Rear thread type: M64×0.75–M54×0.75 / M54×0.75–M54×0.75 / M54×0.75–M48×0.75 (with M48×0.75 filter thread)

• Standard package items: 71F OTA, tube rings, handle, 230 mm Vixen dovetail plate, photographic adapters, 1.25" 45° erecting prism, 8 mm eyepiece, 20 mm eyepiece