Astropy quantities are converted to arrays for indices

[hafarooki]

What is your issue?

When provided as a data variable, an astropy Quantity is kept as a Quantity. But when provided as an index through the coords argument when constructing a Dataset, the Quantity is converted to an array, erasing the units. Is it possible to fix this?

[keewis]

that's to be expected, see the list of operations converting to numpy. You can work around this using a custom index, but this is going to be quite a bit of effort (you can use pint-xarray's index as an example).