Svbony provided Svbony SV503 80ED F7 Doublet Refractor for my review. This is a small 80mm refractor with a doublet lens, one of which is made of S-FPL51 glass. The use of ED glass provides a significant reduction in color halo (longitudinal chromatic aberration) around bright objects compared to a classic achromatic refractor with the same focal length. Also for review, I received a native Svbony SV193 0.8x field-flattener reducer for this specific refractor.
Svbony company has kindly provided me with several eyepieces for testing. One of them – SV190 18mm 1.25″ Ultra Flat Field Eyepiece FMC. A flat field (no curvature), a large eye relief (20 mm) and a field of view of 65 degrees are declared. Interesting!
The focal length of 18 mm is one of my favorites, as it is especially in demand with “fast” telescopes (f\5…f\6) when observing deep space objects (galaxies, nebulae, clusters). With “slow” telescopes (f\8…f\12), the eyepiece can be used for observing the Moon and bright compact objects in deep space.
Svbony SV190 18mm 1.25″ Ultra Flat Field Eyepiece FMC