After getting lucky with a sunrise silhouette yesterday, I decided to continue the experiment. Surprisingly, the results are very sensitive to very small changes in settings - especially exposure compensation and focal length. Changing nothing but focal length from 180 (this shot) to 200 caused the center of the sun to go pure white (looked like a bullseye with red, orange, yellow and white).
Finding a foreground object to silhouette that's in line with the rising sun and free of other distracting elements was more of a challenge than I expected (like I said, yesterday was luck). Of course the opportunities are fleeting since the movement of the sun seems really fast when you're trying to get everything set just right.
And looking into the sun through the viewfinder isn't the greatest, either. Complain, complain.