Askar 50mm f/5.5 Triplet Apo Lens / Guidescope # FMA230
| Article number: | FMA230 |
| Availability: | In stock |
| Delivery time: | In Stock |
Since the FMA135 and FMA180 have hit the market, we’ve received numerous positive feedbacks. It’s really an encouragement for us to further introduce our FMA230 astrograph, hoping to offer more choices for our customers.
The FMA230 features a compound lens system. The front objective lens comprises three lenses, and the posterior reducer is composed of four lenses. Hence, it’s sometimes called a “three at the front and four at the rear” system. With an aperture size of 50mm and a focal length of 275mm, the FMA230 has a relatively fast focal ratio of f/5.5.
The objective lens contains two ED glasses, which help to correct chromatic aberrations. Achieving a three-element apochromatic objective lens in an astrograph of this size is rare and demands more craftsmanship and processing precision. We created this design to deliver better imaging results for our customers.
The FMA230 can function as a standalone lens for both terrestrial and astronomical observation or photography. Simply fine-tune the helical focuser for perfect focus without adding extra optical devices.
The four-element reducer is a 0.84× optical device that transforms the FMA230 into a 50mm-aperture astrograph with a focal length of 230mm and a focal ratio of f/4.6. This reducer plays a vital role in improving image quality, particularly at the edges of the field, making it ideal for sophisticated astrophotography. Even professional full-frame or astronomy cameras can benefit from this reducer, resulting in enhanced and detailed images.
The FMA230 comes with useful standard accessories:
- Artistically pierced tube rings with extended stalks for more room for attached devices.
- Vixen-style dovetail plate, which allows easy attachment to an equatorial mount or tripod.
- Detachable utility handle with dovetail slot for attaching finders, guiders, or ASIAIRs.
- 45° Arca-swiss style slots on the handle for compatibility with camera tripods.
The lightweight and compact FMA230 will undoubtedly take your observing and imaging experience to a whole new level!
Specifications
| Specification | Value |
|---|---|
| Aperture Size | 50mm |
| Focal Length | 275mm (230mm with the reducer) |
| Focal Ratio | f/5.5 (f/4.6 with the reducer) |
| Objective Lens | Triplet air-spaced APO with two ED glasses |
| Imaging System | Septuplet full-frame astrograph (with the reducer) |
| Length | 239mm (with the reducer) |
| Weight (Total including tube ring & dovetail plate) | 1200g |
| Rear-end Thread Type | M48×0.75 (for imaging) |
| Observation Thread Type | 2" socket (for observation) |
| Package Items | An FMA230 astrograph, a pair of tube rings, a Vixen-style dovetail plate, a manual |
