ASKAR 131F f/7.5 APO REFRACTOR
The Askar 131F is an apochromatic quadruplet flat-field astrograph that offers high performance for an exceptionally low price. The quadruplet design makes it perfect for both visual observation and astrophotography. The objective lens features an element of extra-low dispersion glass (ED) that minimizes chromatic aberration.
The Askar 131F is a versatile instrument and excels not just at imaging, but as a grab & go visual telescope (eyepieces & diagonal sold separately).
Unlike traditional refractors, the quadruplet design does not require a separate field flattener and you do not need to calculate precise backfocus. With a large image circle of 44mm, the Askar 131F is a highly capable imaging telescope.
The OTA itself weighs just 7.9kg (9.4kg with tube rings and dovetail bar) and has an overall length of 878mm with the dew shield contracted, making it easy to transport.
The 3" dual-speed rack & pinion focuser is precise and rigid. It is natively compatible with most motorized focusers on the market including the ZWO EAF. The focuser includes 2" and 1.25" visual adapters as well as M48 and M54 camera adapters. On the rear there is a 360 degree rotator with fine rotation angle markings for precise framing. A 2" mounted filter can be attached to the rear M48 camera adapter.
Unlike most refractors, the 131F includes two finderscope bases on either side of the focuser, allowing you to attach both a standard guide scope and control unit such as the ASIAIR without the need for additional accessories. The handlebar also includes a finder-style slot, allowing for even more possibilities.
Specifications
| Optical design |
Apochromatic air-spaced quadruplet with ED glass |
|
Objective diameter |
131 mm |
|
Focal length |
983 mm |
|
Focal ratio |
f/7.5 |
|
Resolving power |
0.89 arc second |
|
Stellar limiting magnitude |
13.29 |
|
Max. magnification |
327.5 x |
|
Light gathering power |
350.22 times the human eye |
|
Mount attachment |
300 mm Losmandy-style dovetail with 1/4"-20 & 3/8" screw holes |
|
Focuser |
3" rack & pinion dual speed 1:10 |
|
Tube weight |
7.9 kg (9.4 kg with dovetail and rings) |
|
Tube length |
878 mm (1026 mm with dew shield extended and photographic adapters) |
|
Tube diameter |
125 mm |
|
Dew shield diameter |
157 mm |
|
Connections |
2", 1.25", M78 x 1, M54 x 0.75, M48 x 0.75 |
|
Focus point (imaging mode) |
73 mm from M48 thread, 91 mm from M54 thread |
|
Focus point (visual mode) |
131 mm from 1.25" adapter, 141 mm from 2" adapter |
|
SKU |
AS-131F |
Items included
- 131F OTA
- Pair of tube rings
- 300mm Losmandy bar
- 2" visual back
- 1.25" eyepiece adapter
- M78 - M54 adapter
- M54 - M54 adapter
- M54 - M48 adapter
- Manual
- Soft carrying case
Instructions
Downloads
 Instruction manual
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