Update README.md

Author: swagner-astro

README.md

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 # lightcurves
 
 This is the lightcurves repository. Check it out: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1OqafFK4FQA_tBwTTnYMG-1D5uhTQ5X0D#scrollTo=european-mechanism) <br>
-or maybe better the new version: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/swagner-astro/lightcurves/blob/main/illustration.ipynb) <br>
+or maybe better the new version: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/swagner-astro/lightcurves/blob/main/illustration_lightcurve.ipynb) <br>
 
 See here for scientific application of this code:
 https://pos.sissa.it/395/868