Several alternatives have been proposed for the reference mission landing site:
63 deg 20 min E, 26 deg 50 min N
67 deg 10 min E, 24 deg 40 min N
67 deg 10 min E, 21 deg 40 min N
The question: Can we find a good location that's closer to the limb? We want that billion-dollar view.
Using the Starry Night program, I checked to see if we could get Earth in frame from those sites. Starry Night produced a trace of the Earth's path in the lunar sky for each location, and shows the size of the Earth you'd get if you use a lens wide enough to include both the lunar horizon and all of Earth's path through the sky.
site-63-20-26-50.gif 204 x 426 17K
site-67-10-21-40.gif 204 x 429 17K
site-67-10-24-40.gif 204 x 429 17K
site-72-00-22-00.gif 203 x 429 17K
site-72-00-26-00.gif 204 x 428 17K
site-80-00-26-00.gif 386 x 367 26K
It turns out that we'll have quite a bit of difficulty getting a decent-sized Earth in the same frame as any part of the lunar landscape or the lunar base. Starry Night gives a very accurate depiction (well, within a pixel or so) of the size of the planet, so these images giveyou a pretty good idea of what the Earth would look like from a given location on the moon. The only thing missing is the lunar landscape.
In all but the last file, the gray grid lines are 10 degrees apart. In the last one, shot from 80 deg E, 26 deg N, Earth was close enough to the horizon that I could crank up the telephone and zoom in; so the grid lines are 5 degrees apart in that picture.
You can see that the closer we get to the limb, the better, as long as the location is obvious to Joe Sixpack when he looks up at the rising moon outside the bar on a clear Friday night. The limit would be at about 83 degrees East longitude; farther than that and Earth will slipping below the horizon. For the long range, we don't want do that because we want the rooms of the Luna City Hotel to have a nice Earth view.
For more on site selection, see section 188.8.131.52 of the Artemis Data book.