Askar FRA400C AP 72mm 400mm f/5.6 Astrograph Apochromatic Refractor

Versatile telescope system for observation and photography
Integrated corrector
Corrects the image field up to full-frame format
M48 filter thread
Includes a standard tripod thread and a Vixen-style mounting rail



The ASKAR FRA is a 5-element Petzval-design apochromat. The objective incorporates three lenses—including an ED glass element—to effectively correct chromatic aberration. Two additional lenses are positioned further along the optical path to flatten the image field. The apochromat is corrected for cameras up to full-frame format.

The retractable dew shield offers excellent protection against stray light. The large focuser is robust enough to support heavy cameras and features a micro-focuser for precise focusing. Connection options include 2" and 1.25" holders as well as an M68x1 thread.

An M48x0.75 adapter is included, making it ideal for cameras requiring a 55 mm back-focus (working distance). Tip: To access the M48 internal thread for 2" filters, simply unscrew the adapter.

A specialist for photography that is also suitable for visual observation: The ASKAR FRA was designed with astrophotography in mind. However, its generous back-focus allows for the attachment of 2" star diagonals. This transforms the astrograph into a superb spotting scope and telescope for both astronomical and terrestrial observation. It is compatible with all standard 2" and 1.25" accessories.

Focusing the camera with the FRA apochromat: The corrector is permanently installed within the optical tube. Once the camera is focused, the correct back-focus distance is automatically achieved, eliminating the need to search for adapters of the precise thickness. Technical Specifications
Optics
Type
Refractor
Design
Apochromat
Aperture (mm)
72
Focal length (mm)
400
Aperture ratio (f/)
5.6
Resolution (arcseconds)
1.92
Limiting magnitude (mag)
11.1
Light-gathering capacity (relative to 7mm pupil)
110
Max. useful magnification (x)
144
Lens design
Triplet
Tube weight (kg)
2.56
Transport length (mm)
317
Internal baffles
Yes
Corrected image circle (mm)
44
Focuser
Type
Helical
Connection (eyepiece side) (inches)
2
Connection thread (camera side)
M72/M54/M48
Back focus (mm)
55
Clear aperture (mm)
76
Motorized
No
Compression ring
Yes
Tilt flange
No
Rotatable
Yes
Filter thread
Yes
Mount
Type
OTA
Mount type
No mount included
Included accessories
Dew shield
Yes
Diagonal/Prism
No
Corrector
Integrated
Reducer
No
Dovetail bar
Vixen-style
Carry handle
No
Transport case
No
Finder shoe
Vixen/Skywatcher level
Eyepiece adapter
2" / 1.25"
Tube rings
Yes
Fields of application
Astrophotography
Yes
Moon & planets
Yes
Nature observation
No
Nebulae & galaxies
Yes
Sun
No (only with suitable solar filter)
Recommended for ...
Beginners
No
Advanced users
Yes
Observatories
No
Product safety

Manufacturer: SHARPSTAR OPTICS CO.,LTD, 3/F, No.5 building, Science and Technology Center, No.79 Jin-Sui Road, 314001 Zhejiang, CN, http://www.sharpstar-optics.com