ASKAR FMA180 objective lens features Triplet air-spaced APO design, includes two pieces of ED (extra-low dispersion) glass, providing excellent correction of chromatic aberration, which lays the foundation for high quality astrophotography and observation.
ASKAR FMA180 reducer features Triplet air-spaced design, combined use with objective lens, providing clear and sharp image, specifically optimized for astrophotography, which is its strong point, you don't have to worry about chromatic aberration that can appear in the image field. Using the f/4.5 reducer makes it capable of capturing clear astrophotos in considerably less time.
When using the special F4.5 full frame reducer, the 40mm aperture, 220mm (f/4.5) focal length ASKAR FMA180 becomes a professional APO refractor with 180mm focal length, both scenery observation and astrophotography, it will present good performance.
For traditional astrophotography, it is difficult to achieve a focal length of less than 200MM with commercially available telescopes. The only choice in this range is the ordinary camera lens. However, the camera lens is not optimized for astrophotography, so the result is not satisfactory.
FMA180 makes it new, if you wanted to capture deep-sky objects, it will get superior optical performance in image like telephoto prime lens.
In addition to photography and observation, FMA180 is also suitable for a high-performance finder/guider of your choice. The overall tube length is 145mm, the small size of FMA180 tips the scales at a mere 395g.
Therefore, the standard package includes a pair of tube rings and a finder bracket, which can be easily attached to the finder base on the market. In addition, the finder bracket can be divided into two parts, among which the dovetail plate can be used alone, and it can be connected to the tripod with standard camera thread and other head. This SWISS standard dovetail can be connected to the corresponding plate slot more conveniently, and it can also attach to the VIXEN narrow equatorial adapter. Hence you can get rich connectivity for both photographic purposes and observation.
Its small size could be directly attached to camera like a normal lens, easy to carry away the view time.
Below are FMA180 usage patterns for reference:
1) Main tube + focuser + reducer + reducer connection extension tube: 180mm F4.5 sextuplet APO flat field correction astrograph lens (recommended photographic mode, product assembled)
2) Main tube + focuser + extension tube 1 + extension tube 2＋reducer connection extension tube : 220mm F5.5 triplet APO lens
1) Main tube + focuser + extension tube 1 + 1.25" adapter: It can be combined with 1.25" star diagonal and eyepiece for standard observation mode or finderscope mode.
2) Main tube + focuser + extension tube 1 + extension tube 2: It can be combined with 1.25" eyepiece for visual observation mode or finderscope mode.
Optical path diagram
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