diff --git a/docker/PYROS_DOCKER_BUILD b/docker/PYROS_DOCKER_BUILD
index e9b15ef..d588fca 100755
--- a/docker/PYROS_DOCKER_BUILD
+++ b/docker/PYROS_DOCKER_BUILD
@@ -1,6 +1,11 @@
 #!/usr/bin/env bash
 
+# Git clone guitastro
+# This could be done directly in the Dockerfile
+# but it is better to do it here because if it failed during the build 
+# we would have to do all the build again...
 [ ! -d "../vendor/guitastro/" ] && git clone https://gitlab.irap.omp.eu/guitastrolib/guitastro.git ../vendor/guitastro/
+[ ! -d "../vendor/guitastro/" ] && echo "Error : git clone of GuitAstro failed => cannot go on with the build" && exit 1
 
 export CURRENT_UID=$(id -u) 
 
--
libgit2 0.21.2