"In astronomy as in other scientific or societal fields, communication is an important aspect that no single organisation can overlook. Especially public research organisations should be accountable to the public for the tax money they use. This is only possible if the public is well informed. But this is even more crucial in order to secure additional funding for new projects.
As one scientist said, perhaps a little bit too provocatively, "the one percent spent on outreach allows one to get the 99 percent to have the project done". This is most likely too strong a statement but the general idea is there. Communication is also important to entertain the necessary excellent relations with the local communities - some of the large astronomical observatories know a lot about this.
Communication is also essential for astronomy to fulfil a fundamental role in modern society: attracting bright youngsters to scientific careers. Although girls and boys are more and more moving away from science, there is a great need for future scientists. And even if the young people won't become scientists, it is important that they are sensitive to science as a whole: as grown-ups, they won't be able to avoid relying on science in their daily life, and they will have to take decisions with a scientific dimension."