It would be great if HOMER included links to websites that provide data such as NASA site
HOMER actually does provide a link to the NASA Surface Solar Energy website. In the Solar Resource Inputs window, try clicking on the "Download From Internet..." button:
If you are connected to the Internet, clicking that button will cause HOMER to request solar data for the specified latitude and longitude from the NREL website. For locations within the US, the NREL website returns data from NREL's own database. For all other locations, the NREL website requests the data from the NASA SSE dataset. All that happens behind the scenes and the data should appear in the table and graph within about a second. Give that a try, it's really handy. If you specify a lat/long outside the US,HOMER refers to the NASA SSE dataset. So depending on what location you request data for, HOMER might ask you to specify a username for NASA on their SSE website.
Please use firstname.lastname@example.org as your NASA SSE username in HOMER2. NASA recently re-configured their website and eliminated the need to validate specific email addresses. To enter this in the HOMER software, open HOMER2, select File >> Preferences, and enter email@example.com into the field for NASA SSE username.
We recognize that finding data is one of the major challenges when running HOMER. We included links to several helpful websites in the help file (look up "finding data" in the index) but if you are aware of others, please let us know and we will add them.