astropy dependency

[asdf-format]

astropy dependency

[mdboom]

It's on our radar. I just went ahead and created an explicit issue for this: #153.

[embray]

That's a good question. Although I would argue that Astropy is not so onerous a dependency, I do think it should be possible to make the pyasdf implementation more generic eventually (for now a lot of the dependency on Astropy is out of convenience for development).

There are a couple areas where decoupling from Astropy is tricky though: Mainly the WCS support. However, although WCS is one of the core data structures in the ASDF format, it is not needed for many files (although its use is broader than Astronomy) and so support for it is optional. To be clear, other readers don't need to depend on Astropy for WCS support either, but Astropy provides most of the required features out of the box. An alternative might be to use a library like AST.

Time and units are two other important features used from Astropy. A longer-term goal would be to support multiple time and unit libraries so long as they support the appropriate interfaces.

[drdavella]

Closing since this is addressed by #153.