# To calibrate an eyepiece micrometer!?!

**URL:** <https://forum.microlist.org/t/to-calibrate-an-eyepiece-micrometer/3240>\
**Category:** Hardware\
**Created:** [September 28, 2025, 1:02pm UTC](https://forum.microlist.org/t/to-calibrate-an-eyepiece-micrometer/3240 "2025-09-28T13:02:34Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![peteeliot](https://avatars.discourse-cdn.com/v4/letter/p/3ec8ea/32.png) [@peteeliot](https://forum.microlist.org/u/peteeliot)\
**Post date:** [September 28, 2025, 1:02pm UTC](https://forum.microlist.org/t/to-calibrate-an-eyepiece-micrometer/3240/1 "2025-09-28T13:02:34Z")

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Hello-

I’m new here. Thanks in advance for any help. I am a naturalist. I have a AM dissecting microscope (10-30x) which I use with an eyepiece micrometer to make measurements on dragonfly nymphs. I can calibrate the micrometer (on a small ruler) with the diopter. However, the diopter runs out of adjustment while the micrometer is still 4% short (resulting in larger measurements). Can I adjust the position of the lenses in the eyepiece to correct for this, or add a spacer under the eyepiece? I will call AM for advice but I thought I would try here first.

Thanks, Pete