Astronomical Telescope Accessories, 50 51 52 53 57 58mm Cemented Doublet Objective Lens Achromatic Optical Focal Length 182mm-987mm DIY Refraction Telescope,for Used in Astronomy(51F189 Green Film)

=========High-concerned chemical : NoneModel Number : YT102319121Diameter : 50 51 52 53 57 58mmfocal length : 182mm-987mm

• Lens edges blackened and internal matte threads effectively suppress stray light and glare, improving image contrast and making faint celestial objects easier to identify.
• Available in sizes of 50mm, 51mm, 52mm, 53mm, 57mm and 58mm, these cemented doublet achromatic lenses fit DIY assembly of refractor telescopes.
• With focal lengths ranging from 182mm to 987mm, they adapt to diverse optical designs for homemade astronomical telescopes.
• The cemented doublet structure achieves achromatic effect, reduces light dispersion and optimizes optical imaging performance.
• Made of professional optical glass, they are ideal for part replacement and modification of telescope assemblies.
• Multiple size options match various inner diameter tubes and meet assembly needs of different refractor telescopes.
• Multi-group multi-element optical glass construction with broadband anti-reflection coating on surfaces, effectively increasing light transmission and reducing reflection loss, delivering bright and sharp imaging.