About this product
Part Number: FMA180
Optical Bench Test
All Askar telescopes are tested in the UK on an optical bench.
This ensures you can be confident your telescope will, from the outset, have well figured optics, negligible false colour and spherical aberration, and no astigmatism (the bane of any optical system!). Star shapes will be round, not triangular, oval or egg-shaped!
ASKAR FMA180 180mm f/5.5 Triplet APO Astrograph Lens & Reducer.
The ASKAR FMA180 features a triplet air-spaced APO design, including two ED (extra-low dispersion) elements that provide excellent colour correction and full frame field flatness.
The FMA180 is a very versatile optic that can also be easily configured as a six-element f/4.5 apochromatic refractor/camera lens, making it an ideal instrument for serious wide-field astronomical or terrestrial imaging.
The heart of the FMA180 is an air-spaced 40mm apochromatic f/5.5 triplet with two ED elements to minimise chromatic aberration. With a native focal length of 220mm, the objective lens is optimised for wide field deep sky imaging.
Included with the FMA180 is a carefully matched Focal Reducer that transforms the overall focal ratio to f/4.5 and focal length to 180mm, yielding flat fields and razor-sharp images with a full-frame DSLR or dedicated astronomy camera.
With the included focuser ring and extension tubes, the FMA180 is easily configured for visual or photographic use. When configured for imaging with or without the focal reducer, the telescope side of the extension tube terminates in a standard M42x0.75 male T-thread for mating to a camera T-ring adapter (not included). The back focus is a standard 55mm, or it can be changed to 99mm by removing an extension tube to allow more freedom to attach other camera accessories.
For straight-through observing with an eyepiece or for use as a guide scope, there’s a standard 1.25” adapter that threads onto an extension tube. The scope can also be configured to work with a 1.25” star diagonal (not included) for visual observing.
When configured as a finder or guide scope, the optical tube mounts in dual rings attached to a standard narrow Vixen-style dovetail. The dovetail riser can be removed to expose a Swiss-Arca mounting plate to attach the scope to a suitable tripod head for visual or photographic use. The plate can also attach to a narrow Vixen equatorial adapter (not included). The rings can be completely removed from the scope when it’s used with a DSLR for handheld shooting or when the camera itself is mounted to a tripod.
- Aperture: 40mm
- Focal Length: 220mm (180mm with supplied reducer)
- Focus Ratio: f/5.5 (f4.5 with supplied reducer)
- Objective Type:
- Triplet Dual ED Air-spaced APO (Objective lens)
- 6 Element Refractor for full-frame astrophotography (with reducer)
- Overall Length: 145mm (with Focal Reducer)
- Overall Length 160mm (Observation Mode no Diagonal)
- Helical focuser travel: 30mm
- Dew Shield Thread: M48x0.75 thread on the front of the dew shield, suitable for 2" filters
- Weight: 395g
- Back-end Adapter: M42x0.75 (photographic Mode) / 1.25" (Visual Mode)
Telescope Field of View Simulator
What's in the box
- FMA180 Body
- Tube Rings
- Finderscope Bracket
- 2x Extension Tubes
- Instruction Manual
- 1.25" adapter (1.25" eyepiece holder)
- Allen key
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