Fix broken link in hess.ipynb
"\n",
"This tutorial explains how to analyse [H.E.S.S.](https://www.mpi-hd.mpg.de/hfm/HESS) data with Gammapy.\n",
"\n",
- "We will analyse four observation runs of the Crab nebula, which are part of the [H.E.S.S. first public test data release](https://www.mpi-hd.mpg.de/hfm/HESS/pages/dl3-dr1/). In this tutorial we will make an image and a spectrum. The [light_curve.ipynb](ligh_curve.ipynb) notbook contains an example how to make a light curve.\n",
+ "We will analyse four observation runs of the Crab nebula, which are part of the [H.E.S.S. first public test data release](https://www.mpi-hd.mpg.de/hfm/HESS/pages/dl3-dr1/). In this tutorial we will make an image and a spectrum. The [light_curve.ipynb](light_curve.ipynb) notbook contains an example how to make a light curve.\n",
"\n",
"To do a 3D analysis, one needs to do a 3D background estimate. In [background_model.ipynb](background_model.ipynb) we have started to make a background model, and in this notebook we have a first look at a 3D analysis. But the results aren't OK yet, the background model needs to be improved. In this analysis, we also don't use the energy dispersion IRF yet, and we only analyse the data in the 1 TeV to 10 TeV range. The H.E.S.S. data was only released very recently, and 3D analysis in Gammapy is new. This tutorial will be improved soon."
]
