These are Long-Term Variability pictures of Sagittarius A.  This was done in collaboration with various observatories, terrestrial and in space.
	If you look at the center of these pictures, you can see a slight dimming of the center spot.  It is a very slight change, about 30% less intensity, but it definitely occurred and it happened over a period of 2 years.
	The next slide is a Short-term Variability study of the same region.
	These pictures and the next were provided by C. Darren Dowell.
	~Melanie Leong~