This article shows that high costs to obtain data in astronomy justifies the use of cloud computing. In such a field, like others in science, there are several benefits when this data is freely available to the whole scientific community. The availability of these data will foster innovative applications to exploit and explore data. These applications could be offered as a service in the cloud. A National Data Center for e-Science could take advantage of these high costs data and offer open data to the community to maximize data accessibility.