Here is a hard to find VERY lightly pre-worn, white T-Shirt, size XL that has a graphic on the front of the shirt. At the top, the words: Gamma Ray Astronomy Whipple Observatory with an interesting design in the middle---an astronomer would understand. Nothing on the back. The T-Shirt measures 25 inches across the chest measured under the arms and from the back of the neck band to the bottom hem is 30 ½ inches. No holes or stains and in very good condition (don’t think it was ever worn!) 100% cotton.

And just so you know...
http://en.wikipedia.org/wiki/Fred_Lawrence_Whipple_Observatory
The Fred Lawrence Whipple Observatory is an astronomical observatory owned and operated by the Smithsonian Astrophysical Observatory (SAO) and is their largest field installation outside of their main site in Cambridge, MA. It is located near Amado, Arizona on the slopes of Mount Hopkins.

Research activities include imaging and spectroscopy of extragalactic, stellar, and planetary bodies, as well as gamma-ray and cosmic-ray astronomy.