Even a hastily-assembled screencast can reveal a treasure trove of opportunity. Watch this few minutes of introduction to exploring images in Google Sky, and to using Aladin software to create astroimages from the world’s store of online data. This is great fun, and it can be done in a class period.
A little technical stuff: While Google Earth can be accessed through Google Maps using just a browser, the Sky, Moon and Mars options seem to require the desktop version of Earth. Google Sky can be accessed separately (sky.google.com will do the trick), and it has an excellent set of options for exploring astroimagery, including slider bar options for varying the visibility of each image overlay, and it is wrapped with helpful scaffolding, such as this FAQs section. But the online version of Sky seems to lack the embedded documentation, including the links through to SIMBAD, from which the Aladin applet can be accessed. The Aladin applet can be accessed directly online. So the bottom line is that it works best to install Google Earth, explore Sky in that context, and put students just a couple of clicks away from exploring the sky and generating their own image of any section of it they choose, but there are lots of workarounds for those who can’t install Google Earth.