Askar 40 mm f/5.5 Triplet Apo Lens And Guidescope
- Askar FMA180 40 mm aperture apochromatic telescope and camera lens features multiple applications
- Has a three-element objective lens with TWO ED elements for superb color correction and great image quality
- Can be used as a finder/telescope/guide scope
- Has 220 mm focal length; focal ratio of f/5.5
- Includes 3-element focal reducer and spacers to configure as a 6-element f/4.5 Apo telescope w/180 mm focal length for wide-field astroimaging
- Includes tube mounting rings, Vixen-style dovetail, and Arca Swiss mounting plate for a variety of configurations
This Askar FMA180 Lens/Telescope is a premium multi-functional optical instrument. It sports a 40 mm ED triplet objective to deliver superb image quality. It has optical performance at f/5.5 as a finder/small telescope/guide scope. It can also be easily configured as a six-element f/4.5 apochromatic refractor/camera lens, with the included optical accessories. That means it can become an ideal instrument for anyone wishing to do wide-field astronomical or terrestrial imaging.
The heart of the 40 mm f/5.5 Triplet Apo Lens And Guidescope from Askar is an air-spaced 40 mm apochromatic triplet with TWO ED elements to minimize chromatic aberration. With a focal length of 220 mm, the objective is optimized and tested for demanding astronomical visual work as well as imaging applications. The objective is carefully matched to the 3-element focal reducer which is included with this package, that transforms the overall focal ratio to f/4.5. With a resulting focal length of 180 mm, using that flattener, the Askar FMA180 Lens/Telescope provides flat fields and razor-sharp images. This makes it ideal to use with your existing full-frame DSLR or dedicated astronomy camera.
NOTE: An image may show the product used with a camera and tracker, for illustration purposes only. This product does NOT include a camera or a tracker/mount.
With the included focuser ring and extension tubes, the FMA180 is easily configured by the user for doing either visual or photographic work. When configured for imaging with or without the focal reducer, the telescope side of the extension tube terminates in a standard M42x0.75 mm male T-thread for mating to a camera T-ring adapter (not included). The back focus is a standard 55 mm, or it can be changed to 99 mm if the user wishes, 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 to extension tube. The scope can be configured to work with a 1.25” star diagonal (note: a star diagonal is 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 an Arca Swiss mounting plate to attach the scope to a suitable tripod head. The plate can also attach to a narrow Vixen equatorial adapter if you have one, (not included).
The rings can be removed from the scope for use with a DSLR for handheld shooting or when the camera is tripod-mounted. Then the scope is working just like a camera lens. The overall tube length is 145 mm in photo mode and 160 mm in visual mode without a star diagonal. The FMA180 Askar 40 mm f/5.5 Triplet Apo Lens weighs just 395 g (0.87 lb).
- Aperture: 40 mm
- Focal Length: 220 mm
- Focus Ratio: f/5.5
- Objective: Triplet Dual ED Air-spaced APO
- Sextuplet Lens for full-frame astrophotography (with reducer lens attachment)
- Overall length: 145 mm (photographic mode)
- 160 mm (visual mode without star diagonal)
- Weight: 395 g
- Back-end Adapter: M42x0.75 (photographic mode) -
- 1.25" Adapter (visual mode)
- Accessories Included:
- FMA180 Body, Pair of tube support rings, Finder scope bracket, Two extension tubes, 1.25" Adapter, Allen Wrench, User Manual