I buy stuff to sell on eBay and found an Astros coffee mug today. I went online to research when they used this particular logo and found this site that shows the history of teams' logos for all sports.

I thought folks here might find it interesting:

http://www.chriscreamer.com/index.php

In this case, the cup is the 1975-1993 logo. I think I used this site for an Orioles mug that I could the date down to about a three year time frame because it was before the use of 5 digit Zip Codes. It always helps to give a time frame for items.

If anyone wants to see the mug, let me know and I'll pass along my seller ID.