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The Askar ACL200 F/4 is a 4-element apochromatic refractor with a built-in 2-element corrector and two ED (extra-low dispersion) lenses, with the form factor of a traditional telephoto lens. Unlike traditional camera lenses, the ACL200 is designed specifically for the demands of astrophotography and is corrected across a full-frame image circle and has minimal chromatic aberration and distortion. Perfect for wide-field imaging on star trackers and compact enough to travel with.
Note: Unlike typical camera lenses, this is manual focus only.
Features
- Focal length 200mm
- Adjustable focal ratio from F/4 to F/22 with 50mm aperture
- Coarse and fine focus rings for smooth and accurate manual focus adjustment with 1mm precision
- Standard Vixen dovetail plate with 3/8" and 1/4" female threads for connecting to camera tripods
- 360° rotatable collar for quick and easy framing of targets
- Included metal lens hood to keep out stray light and dew
- Compatible with 82mm screw-in filters or 2" screw-in filters with included adapter
- 135mm body length (without hood) and lightweight at 1.8kg
In order to reach the correct back focus distance of 55mm with a DSLR or Mirrorless camera, a camera-specific T-ring and additional adapters may be required:
- Canon EOS: camera flange distance (44 mm) + Baader Wide T-ring for Canon (11 mm) + Baader S52-M48 inverter (0 mm) = 55 mm.
- Canon R: camera flange distance (20 mm) + Baader Wide T-ring for Canon R (8.3 mm) + Baader S52-M48 inverter (0 mm)+ M48 24-35mm variable adapter (set to 26.7 mm) = 55 mm.
- Nikon: camera flange distance (46.5 mm) + Baader Wide T-ring for Nikon (8 mm) + Baader S52-M48 inverter (0 mm) = 55 mm.
- Nikon Z: camera flange distance (16 mm) + Baader Wide T-ring for Nikon Z (8.3 mm) + Baader S52-M48 inverter (0 mm)+ M48 24-35mm variable adapter (set to 30.7 mm) = 55 mm.

Optical design |
Apochromatic Sextuplet with two ED elements |
Objective diameter |
50 mm |
Focal length |
200 mm |
Focal ratio |
f/4-f/22 |
Mount attachment |
Arca-Swiss style tripod foot with 3/8" and 1/4" threads |
Focuser |
Coarse and fine manual focus rings |
Focus distance | 3 m - infinity |
Camera connection |
M48x0.75 male thread with 5mm height (camera ring sold separately) |
Backfocus |
55 mm |
Lens weight |
1.8 kg |
Lens length |
135 mm, 195 mm with hood |
Diameter |
98 mm with hood |
SKU |
AS-200 |





A very powerful yet compact lens, this will suit me nicely for wide angle deep sky astrophotography and at the same time make an excellent travel kit ...
Very impressed with the product and more especially the service from the Testar people.
The Askar 200 is a lens designed mainly for astronomical use but excells at traditional photography.
For astronomical use, I really appreciated the focusing system with double rings - the first is used for traditional focusing while the second ring is used to refine the focus with extreme precision. Once the optimal position is reached, the focus can be locked by a ring nut with a screw in order to avoid any movement.
Another thing I found useful is the 2-inch internal filter holder, just unscrew the rear part and you access the compartment with the thread to screw in any filter.
The lens comes with a practical unscrewable upper bracket that can accommodate various accessories such as the ASIAIR, mini pc, guide telescopes etc. while the lower dovetail is the classic Vixen-style. The lower dovetail ring has a release screw to rotate the lens in order to obtain the desired framing.
In the photographic field, by unscrewing the lens hood, you can mount a filter holder and use classic plate filters. Using extension rings it can be used as a macro lens with excellent results.