The Askar 91F 91 mm f/6.7 quadruplet APO tube is designed for astronomy enthusiasts and professional astrophotographers who seek impeccable optical and mechanical performance. This compact and ultra-portable telescope is an excellent choice for both visual and photographic purposes.
The Askar 91F tube, with a diameter of 91 mm and a focal length of 609 mm, features a focal ratio of f/6.7. The color-corrected ED triplet objective and the built-in field flattener lens ensure distortion-free, precise sharpness across the entire field of view. The telescope provides a 44 mm image circle, making it perfectly suitable for imaging with full-frame sensors. The system's advantage is that, similar to Petzval optics, there is no need to calculate the backfocus value. With the optionally available 0.75x reducer, you can achieve an extremely fast focal ratio of f/5 for landscape astrophotography.
The dual-speed, 3" rack and pinion focuser allows for precision adjustments and can rotate 360°. The focuser features M64, M54, and M48 threaded connections, providing wide compatibility with various accessories and cameras.
Thanks to the practical tube rings, Vixen-style dovetail bar, and handle, the Askar 91F is easy to mount and transport. The telescope also includes two dovetail shoes for attaching additional accessories. The retractable dew shield helps protect the lenses from moisture and dew.
The Askar 91F tube alone weighs only 3.92 kg and is 513 mm long, making it ultra-portable and an ideal choice for trips or locations where easy transportability is crucial. The Askar 91F quadruplet APO tube delivers outstanding performance in quality optical solutions, making it an excellent companion for astronomical adventures.
Particularly useful for nature observers, the basic package includes an amici prism that provides an upright image, as well as 20 mm and 8 mm eyepieces, offering 30x and 76x magnification.
Main features of the Askar 91F apochromat:
- Diameter: 91 mm
- Focal length: 609 mm
- Focal ratio: f/6.7
- Color-corrected ED triplet objective and field flattener lens
- 44 mm image circle, full-frame compatible
- 3" dual-speed, 360° rotatable focuser
- Camera connection: M64, M54, and M48
- Tube rings, dovetail bar, handle
- Two dovetail shoes on the tube
- Retractable dew shield
- Weight: 4.5 kg (with tube rings and dovetail bar)
- Size: 513 mm
- Ultra-portable travel telescope for visual and photographic use
- 1.25" amici prism
- 20 mm and 8 mm eyepieces
