What do the code letters and numbers on the objective housing stand for?
• Degree of optical correctness: (A/SP/PL) = Achromat / Semi-Plan / Plan • Magnification: (40/100/400/1000) = 40x/100x/400x/1000x • Numerical Aperture or “N.A.”: Refers to light gathering capability and resolving power of the objective and it is key to match the microscopes’ condenser lens to the highest power objective. A 40x objective should be matched to a N.A. 0.65 condenser, a 100x objective matched to a N.A. 1.25 condenser. • If immersion oil is required as a media for the lens, it may list: “OIL” • Focal Length of the optical system using that objective: 40x = 160 • Recommended cover slip thickness for optimal viewing: 0.17 Go to Top Q: Can you give us a sample of objective housing? A: Here is a sample Top Line: A / 40 / 0.65 Bottom Line: 160 / 0.17 Deciphered, this means the objective is a standard achromat, 40 power, has a 0.65 Numerical aperture, a focal length of 160 mm, and recommended cover slip thickness of 0.17 mm. Go to Top Q: What does the “R” after the 40x or 100x obj
