Astronomical telescopic lens 70 mm series double split lens (free abspacer) Calibre: 70 mm (actual outer diameter size: 72 mm) Focal length: 300, 360, 400, 500, 700, 900 Key features and benefits - Versatile focal length options for flexible observing: choose among 300, 360, 400, 500, 700 or 900 mm to suit different targets and telescope configurations. - Double split lens design: built for astronomical use with a configuration that supports stable performance in typical observing setups. - Free abspacer included: adds compatibility with mounting systems and helps fit various assemblies. - Clear compatibility notes: calibre 70 mm and outer diameter 72 mm are specified to aid fitting with standard 70 mm tube assemblies and adapters. - Straightforward integration: designed as an interchangeable lens component for 70 mm series equipment, enabling simple replacement or upgrading in compatible systems. Function and performance considerations - Purpose built for astronomical observations requiring adjustable focal lengths within a 70 mm series framework. - The listed focal lengths provide a range of magnification options when paired with compatible optics and mounts. - The free abspacer and the 72 mm outer diameter size assist with correct alignment and fit in suitable housings. Size and compatibility details - Calibre: 70 mm - Outer diameter: 72 mm - Available focal lengths: 300, 360, 400, 500, 700, 900 - Includes free abspacer for compatible assemblies Practical applications and use scenarios - Planetary and lunar observing: select a focal length to balance field of view and detail, enabling clear views of craters, mare boundaries, and planetary disks. - Educational demonstrations: use different focal lengths to illustrate how magnification and field of view change with focal length in a classroom or astronomy club setting. - Replacement or upgrade in 70 mm telescope systems: when upgrading components, the 72 mm outer diameter and free abspacer help maintain compatibility with standard 70 mm tube assemblies and adapters.