Wow, from a quick browse, I think the moon crater image from the 1850s is what I find most technically impressive because it intersects telescope optics, negative chemistry, and printing chemistry. A 3683x2920 pixel image can be downloaded. <a href="http://search.getty.edu/museum/records/musobject?objectid=44715" rel="nofollow">http://search.getty.edu/museum/records/musobject?objectid=44...</a>