LROC WAC topography of Sinus Iridum, blue shows the lowest areas and red the highest. From promontory to promontory Sinus Iridum is 235 km across. Image credit: NASA/GSFC/Arizona State University

I love false-color mosaics of the lunar surface — I suppose Clementine is to blame for that. Yes, I’m a moon geek. Shut up. This topographic image of Sinus Iridium is from the LRO camera, currently in orbit and discovering exciting new things.

Wow – five spacecraft launched to the Moon in three years! The latest is China’s second lunar orbiter, Chang’e 2, which was launched 1 October 2010 and arrived at the Moon on 6 October. Chang’e 2 carries a higher resolution camera than Chang’e 1 that may help Chinese scientists scout out the proposed landing site for their upcoming lander/rover, Chang’e 3. Currently the Chinese lander is slated to land in Sinus Iridum (Bay of Rainbows) sometime before 2013. Why Sinus Iridum? The WAC topographic map shows the area to be very flat and nearly featureless. However as the LROC Narrow Angle Camera (NAC) keeps showing us, there are no featureless spots on the Moon – everywhere on the Moon is fascinating!

(Emphasis mine, because… YES. THIS.) I hope the Chinese lander makes it to Iridium, and that they share their data!

Eventually I had to get back to the series naming I started with, right? This week’s edition would be better-named as “Randomspam”, but oh well. To start, a lovely image of the Iris Nebula by Alvin Jeng.

Next, a page from the Dunhuang Star Atlas, a Chinese work dating from 649-684 AD:

This ancient Chinese map of planet Earth’s northern sky is part of the Dunhuang Star Atlas, one of the most impressive documents in the history of astronomy. The oldest complete star atlas known, it dates to the years 649 to 684, discovered at the Silk Road town of Dunhuang in 1907. A recent analysis that examines the accuracy and projections used to make it notes the atlas marks positions of over 1,300 stars and outlines 257 Chinese star groups or asterisms. The star positions in the hand drawn atlas were found to be accurate to within a few degrees. In this example showing the north polar region, a very recognizable Big Dipper, part of the modern constellation Ursa Major, lies along the bottom of the chart. An additional 12 charts depict equatorial regions in 30 degree sections and also include a grouping resembling the modern constellation Orion. The atlas is on display at the British Library in London to celebrate the International Year of Astronomy.

On June 15th, the LOIRP released another Lunar Orbiter image, this time of the Apollo 12 landing site:

(There’s also a version at the site without annotations, if you want it. Both images come in a large version.)

Finally, as Saturn approaches its equinox in August, Cassini is recording interesting nearly-edge-on images of Saturn’s rings, and a tiny moon among them:

(You really need to see them large to get the full effect. I hate how image sizing puts kinks in diagonal lines, blah.)

To understand what you’re seeing, I highly recommend this article by Phil Plait, as he does a great job explaining what’s going on and why it’s significant. Below is another view of the tiny moon Daphnis, chugging along in Saturn’s rings.

An interesting lineup of spaceworthy watches, from Yuri Gagarin’s Shturmanskie to the Omega Speedmaster Professional, worn on the Apollo moon landings, and the Fiyta Chronograph, worn by Chinese taikonauts. Vote for your favorite!