Extracting the lon and lat values only from indexes where the value isn't NaN

[ytmben]

I have the following Data array and I want to export a list of lons and lats to a .csv or .txt, but only for lonlat pairs have have a value ~NaN.
Here is my array:

<xarray.DataArray 'deptho' (latitude: 72, longitude: 83)> Size: 24kB
array([[      nan,       nan,       nan, ...,       nan,       nan,
              nan],
       [      nan,       nan,       nan, ...,       nan,       nan,
              nan],
       [6.672306 , 6.672306 , 7.5111613, ...,       nan,       nan,
              nan],
       ...,
       [      nan,       nan,       nan, ...,       nan,       nan,
              nan],
       [      nan,       nan,       nan, ...,       nan,       nan,
              nan],
       [      nan,       nan,       nan, ...,       nan,       nan,
              nan]], shape=(72, 83), dtype=float32)
Coordinates:
  * latitude   (latitude) float32 288B 31.02 31.06 31.1 ... 33.9 33.94 33.98
  * longitude  (longitude) float32 332B 32.54 32.58 32.62 ... 35.88 35.92 35.96
Attributes:
    long_name:      Bathymetry
    standard_name:  sea_floor_depth_below_geoid
    units:          m

Any suggestions?