The Houston Astros have two establishment dates, and they honour them equally and frequently. The first date is when their franchise played their first game in 1962 as the Houston Colt .45s, the other when they became the Astros three years later.
So despite a big celebration for the clubs 50th anniversary in 2012 they’ll be marking their half-century as a ballclub once again in 2015.
The logo, which we at SportsLogos.Net can confirm will appear as a patch on the team jerseys, is for the 50th anniversary of the name change from Colt .45s to Astros. It features former home stadium the Astrodome below the original Astros team jersey wordmark, a 50 and the years 1965 2015 in between them.
As of yet the only appearance we’ve seen of this logo publicly is from the MLB.com shop where it appears on the t-shirt you see at the top of this post. It’s possible this was released a little prematurely.
Houston as not released their promotional schedule for the 2015 season so we’re not sure of any other plans for the anniversary at this time, in 2012 the team wore various different throwback uniform designs throughout the season.