# 4.6.1.1.2. eqcorrscan.core.bright_lights.coherence

`eqcorrscan.core.bright_lights.``coherence`(stream_in, stations=['all'], clip=False)

  Determine the average network coherence of a given template or detection.

  You will want your stream to contain only signal as noise will reduce the coherence (assuming it is incoherent random noise).

  Parameters: | stream_in (obspy.core.stream.Stream) The stream of seismic data you want to calculate the coherence for. stations (list) List of stations to use for coherence, default is all clip (tuple) Default is to use all the data given (False) - tuple of start and end in seconds from start of trace
  Returns: | tuple of coherence and number of channels used.
  Return type: | tuple