 Humanity looks upon the universe with never-ending curiosity and wonder. With state-of-the-art telescopes like those at ESO, we can take the most stunning images that the universe beholds to us. But to astronomers, ESO's telescopes are not just about a pretty picture. They are tools to collect data through which remarkable discoveries are made. Observing time on each of ESO's telescopes is highly sought after. Astronomers have to request to use this time by submitting proposals to the OPC. So the OPC stands for the Observing Programs Committee and essentially it's a peer review panel. It's consisting of referees that have been recruited from around the world and have expertise in all the scientific areas that ESO caters for. Every semester ESO receives of the order of 900 proposals submitted by a total of more or less 3,500 distinct scientists all over the world from more or less 50 countries. And the acceptance rate of course is pretty low because the competition is strong. Typically only one out of four proposals gets to see the telescope light. It can be difficult to get time on our telescopes. For instance, we have one new instrument that's been offered called Muse and that is one of the most heavily demanded instruments that we have amongst our suite of instrumentation at the moment. So it very much depends on how new it is and how wide a community it's serving. Twice a year astronomers gather at the OPC to discuss their proposals. In May 2017 they met for the 100th time, deciding the fate of thousands of astronomers whether or not they would be granted time on one of ESO's telescopes. To mark this special occasion they met in the beautiful Spinetto Abbey in Italy. The amount of time available on the telescope compared to the amount of time requested by the observers there's a big difference, often a factor of five or there about. So there are tough decisions made all the time. The most interesting part of my job I would say it's the interaction with the OPC members. These are very distinguished astronomers from all over the world so it gives us and in particular a very international view on where astrophysics is going. But the thing you're really after is, is this really signs that is going to make a large difference to the way that we perceive this particular topic or subtopic. The scientific ideas are sorted into four main themes so that judges are equipped with the relevant expertise. The first is the extragalactic distance scales and cosmology. Then we have a second category which is for galaxy formation and evolution, galaxy dynamics. The third one is star formation and planetary systems including exoplanets. And the fourth one is stellar evolution. For each theme there are six allocated experts who discuss each proposal and grade them via a ranking system. The referees read between 70 and 80 proposals each. As the meeting progresses the different panels eventually come to an agreement. The fate of the astronomer has been sealed. It's really clear that the top one or two science projects that people put forward they really grab everyone's attention, it's really clear those are the ones that we want to do. And then there are the ones that really don't capture our attention and those are clear. Then there are lots of proposals in the middle that are all really really good science and it's really hard to choose between them because all of them are making major steps forward in their science. After the results have been collated and accepted by ESO's director general the astronomers are notified and the successful ones prepare for the next stage, observation. Most of the time the support scientists in the control room execute the observations and send the data back to the astronomers who may be anywhere in the world. Months later after much analysis and discussion the results are written up in the form of a paper assessed in a peer review journal and eventually published. There are also proposals which are so novel in their approach that you have to really be careful that you are not losing something like a future Nobel Prize for instance.