The Askar 71F Flat-Field 71 mm 71/490 f/6.9 is a versatile optical instrument whose optical characteristics make it exceptionally well suited both to astrophotography enthusiasts and to visual observations. The telescope comes with a complete set of accessories required to attach the optical tube to a mount and begin observations immediately.
 
At the heart of this telescope is a four-element, air-spaced apochromatic optical system. To ensure the best possible correction of chromatic aberration, this model uses a single low-dispersion glass (ED) element. In addition to excellent colour rendition, the Askar 71F Flat-Field 71 mm 71/490 f/6.9 features negligible field curvature, ensuring that even without an additional flattener, images remain free from noticeable distortion at the edges of the frame.
 
The capabilities of this telescope are not limited solely to astrophotography. The instrument can also be used for visual observations after attaching a diagonal or 1.25" or 2" eyepieces.
 
In addition to its excellent optical parameters, the Askar 71F Flat-Field 71 mm 71/490 f/6.9 is distinguished by the high quality and precision of its mechanical components. The robust focuser allows large astrophotography cameras to be mounted, while the CNC-machined mounting rings and Vixen dovetail ensure complete stability of the optical tube.

Key features of the Askar 71F Flat-Field 71 mm 71/490 f/6.9 telescope

• high-quality astrograph with a low-dispersion (ED) element that reduces chromatic aberration
• advanced optical design providing excellent field-curvature correction without the need for an additional flattener
• possibility of mounting filters with an M48x0.75 thread
• fully illuminated image circle diameter providing full-frame coverage
• suitable for visual observations as well

Technical specifications

• optical design: apochromatic refractor
• lens configuration: air-spaced ED quadruplet
• number of low-dispersion elements: one
• front lens diameter (aperture): 71 mm
• focal length: 490 mm
• focal ratio: f/6.9
• fully illuminated image circle diameter: 44 mm
• full-frame sensor compatibility: yes
• connection adapters: M64x0.75 - M54x0.75; M54x0.75 - M54x0.75; M54x0.75 - M48x0.75
• maximum working distance (for astrophotography) from the base of the M48x0.75 thread: 82.5 mm
• maximum working distance (for astrophotography) from the base of the M54x0.75 thread: 100.5 mm
• maximum working distance (visual observations) from the end of the 1.25" eyepiece holder: 117 mm
• maximum working distance (visual observations) from the end of the 2" eyepiece holder: 127 mm
• compatible eyepieces / diagonals: 1.25" / 2"
• filter mounting capability: yes, with an M48x0.75 thread in the M54x0.75 - M48x0.75 adapter
• focuser diameter: 2.4"
• focuser type: rack & pinion, dual speed with 1:10 reduction
• rotator: yes, 360°
• mount attachment: Vixen dovetail
• dew shield: yes, retractable
• optical tube length (with photographic adapter and extended dew shield): 473.4 mm
• optical tube weight without accessories: 2.5 kg
• optical tube weight with accessories: 3.0 kg

Included items

• Askar 71F Flat-Field 71 mm 71/490 f/6.9 optical tube
• mounting rings
• 230 mm Vixen dovetail bar
• photographic adapters
• documentation

Warranty

24 months