62mm achromatic telescope objective lens 400mm

Product Description

Vintage US-Made 62mm Achromatic Telescope Objective Lens – 400mm Focal Length (f/6.5) – Pristine Surplus Condition

A premium American-made cemented achromatic doublet objective lens in pristine, like-new surplus condition. With a clear aperture of approximately 62mm and a focal length of ~400mm (f/6.5), this lens is an excellent core component for building a high-quality, wide-field “rich-field” refractor telescope—ideal for expansive views of star clusters, nebulae, and the Milky Way.

🔭 Key Specifications:

• Aperture: ~60mm clear (62mm outer diameter including bevel)

• Focal Length: ~400mm (f/6.5 focal ratio)

• Design: Cemented achromatic doublet (crown + flint glass)

• Coating: Single-layer anti-reflection (vintage magnesium fluoride type)

• Edge: Frosted/ground for secure mounting

• Thickness: ~17.5mm total (robust meniscus form)

• Condition: Pristine – like new, surplus US stock

🛠️ Ideal Applications:

• Amateur Telescope Making (ATM): Build a compact, wide-field 60mm refractor for deep-sky observing

• Rich-Field Astronomy: Perfect for low-to-medium power views of star fields, open clusters, and large nebulae

• Educational Projects: Optics demonstrations, magnifier setups, or introductory astronomy

• Vintage Optics Collection: Example of quality mid-century American optical manufacturing

• Astrophotography: Potential use as a guide scope or wide-field imaging objective