60mm achromatic doublet lens 350mm focal length

Product Description

60mm Achromatic Doublet Lens – ~350mm Focal Length, Broadband AR-Coated – Pristine Surplus Optic

A high-quality cemented achromatic doublet lens in pristine surplus condition. With a 60mm clear aperture and ~350mm focal length (f/5.8) , this positive converging lens delivers sharp, color-corrected imaging with minimal chromatic aberration—a significant upgrade over simple single-element lenses. The subtle broadband anti-reflection coating enhances transmission and contrast, making this optic exceptionally versatile for astronomy, laser work, and general optics experimentation.

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🔍 Key Specifications:

• Diameter: 60mm (clear aperture ~56–58mm)

• Focal Length: ~350mm (f/5.8 focal ratio)

• Construction: Cemented Fraunhofer achromatic doublet (crown + flint glass, likely N-BK7 / F2)

• Shape: Biconvex (symmetrical or near-symmetrical curves)

• Edge Thickness: ~9.3mm (center thickness ~12–15mm)

• Coating: Single-layer MgF₂ broadband anti-reflection – subtle bluish/purple bloom, >95% transmission

• Edge Finish: Ground/frosted – no chip, no bevel damage

• Condition: Pristine – Like New / New Old Stock (NOS)

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✅ Condition & Notes:

• Condition: Excellent – Pristine, No Scratches or Coating Defects

• Origin: Surplus from US optical stock, carefully stored

• Optical Quality: Surfaces are clean, no haze, separation, or delamination. Coating uniform and intact.

• AR Coating Note: Subtle blue/purple reflection (MgF₂) – indicates professional-grade coating, not heavy rim-coat of cheap consumer optics.

• Includes: Lens only – no cell or mounting hardware

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⚙️ Optical Performance Benefits:

• Achromatic Design: Drastically reduces chromatic aberration vs. singlets – clean, sharp image across visible spectrum

• AR-Coated Surfaces: Suppresses stray light, ghosting, and flare; improves low-light performance for astronomy

• Fast f/5.8 Ratio: Bright, wide-field views ideal for deep-sky observing

• Compact & Lightweight: Easy to mount in DIY tubes or standard 60mm lens cells

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🛠️ Ideal Applications:

🔭 DIY Refractor Telescope Objective:
Build a rich-field 60mm short-tube refractor – perfect for sweeping star fields, open clusters (Pleiades, Beehive), and bright nebulae (Orion). Excellent starter scope or portable grab-and-go instrument.

💡 Beam Collimation & Expansion:
Collimate or gently expand laser beams (HeNe, diode, 532nm) with minimal wavefront error. Suitable for optics bench setups, interferometry, or alignment systems.

📷 Projection & Imaging:
Use as a condenser lens in projectors, magnifier objective, or simple camera lens for experimental photography. Broadband AR coating ensures high transmission from blue to red.

🧪 Education & Experimentation:
Ideal for student labs, hobbyists, and researchers studying:

• Lens aberrations and ray tracing

• Achromatic doublet performance vs. singlets

• Optical system prototyping and breadboard setups