Description
A low-power AO Spencer scanning objective, optics cleaned and clear. Correctly identified as a biological RMS objective, not a stereo lens.
Bench report
- Functional
- Optics clear after a light cleaning. Standard RMS thread, undamaged, turns freely. This is a biological objective on a standard RMS thread. The N.A. marking plus the thread settle that; stereo (Greenough) objectives are marked with working distance instead of N.A.
- Cosmetic
- Normal age and handling wear to the barrel. No colour band. Engraving legible. Ships in the screw-top canister shown. I have a second 3.5X of the same spec listed separately. They came off different microscopes and are not a matched pair, so buy whichever photographs better for you.
- Tested
- Optics inspected under direct light and against a bright field. Front and rear elements examined at magnification. · No haze, no fungus, no balsam separation, and no chips visible in the glass. · RMS objective thread inspected for burrs, cross-threading, and dings. None found. · Every legible engraving read under raking light and transcribed exactly as marked (see Specifications). · Optics cleaned with lens solution, then re-inspected after cleaning. Clear front and rear.
- Not tested
- NOT mounted on a microscope. I do not have a matching stand for it, so resolution, field flatness, parfocality, and working distance at magnification are NOT verified. · No disassembly, recollimation, or internal service performed. · Sold as a used optical component, not as a calibrated or certified instrument.
Specifications
- Maker
- American Optical / AO Spencer
- Magnification
- 3.5X
- Numerical aperture
- N.A. .09
- Optical tier
- Achromat (no Plan marking present)
- Thread
- RMS (Royal Microscopical Society) standard
- Full engraving
- AO SPENCER / 3.5X / N.A. .09
- Objective type
- Biological, RMS. Not a Greenough stereo objective
- Optics
- Clear. Lightly cleaned on the bench
- Storage
- Screw-top canister included