Looking at `replicate` we probably want to copy `'precision', 'in_subfmt', 'out_subfmt'` as well:
```
        # Optional or non-arg attributes
        attrs = ('isscalar', '_delta_ut1_utc', '_delta_tdb_tt',   # <== These should *not* be copied
                 'lat', 'lon', 'precision', 'in_subfmt', 'out_subfmt')
``` 
Same applies for `__add__`.