For the potential user it is important to know how to get which sentinel data. There are several possibilities and ways. In the following the two most common platforms will be described.
The first data access takes place via the Sci-Hub of the European Space Agency (ESA), which can be reached at: https://scihub.copernicus.eu/ and https://scihub.copernicus.eu/dhus/#/home respectively. This is an Open Access Hub, where you get free access to Sentinel-1, Sentinel-2 and Sentinel-3 after registration. There are several search options: AOI, sensor, product, date and cloud coverage.
The second data access is CODE-DE (Copernicus Data and Exploitation platform) (in German), available at https://code-de.org. Registration is also required and free of charge. The service also offers Sentinel-1 & -2. There is an open search and presentation service and a collection of tools for analysing sentinel data. The fee-based access also allows the use of the online processing environment.
Search for cloud-free (cloud coverage up to max. 10 %) Sentinel-2 images of the city of Frankfurt am Main taken in the second half of 2017.
How many records can you find at the Copernicus Hub?
How many records can you find in Code-DE?
Why do you find different numbers of data records? (Note: Search for naming conventions of the Sentinel-2 data)