Word for magnifying eyepiece in scientific instruments

(Mostly) historic scientific instruments sometimes have a telescope-like device mounted on them in order to be able to read a very fine scale accurately.

My understanding is that telescopes are used to magnify things far away, where for a magnifying eyepiece I imagine something mobile, such as a jeweller might use. So is there a word for a tubular optical instrument used to magnify things close-by?

here are a couple of examples -

I believe that it would depend on the form of the eyepiece. If it contains a single lens it could be simply a 'lens' or a 'magnifier'. If it consists of two or more lenses it would be a 'microscope'. It would be a very specialised, low power, fixed focus microscope of use only for its intended task but it would have an object lens and an ocular lens so the optical principles would be the same as any other optical microscope. Why the original refers to it as a 'telescope' I have no idea since the optics are completely different.

A jeweller would use a "Loupe."

These can range from handheld magnifying glasses, to ones that clip onto glasses or monocular lenses.

It is a filar micrometer (eyepiece).

A filar micrometer is a specialized eyepiece used in astronomical telescopes for astrometry measurements, in microscopes for specimen measurements, and in alignment and surveying telescopes for measuring angles and distances on nearby objects. The word filar derives from Latin filum, meaning "a thread". It refers to the fine threads or wires used in the device.