Flying around the Moon

 Identify Lunar Features unsing this great free program:

Virtual Moon Atlas

Flying north from the South Pole.   Mare Nectaris is to the right in the distance. 

We always see the same face of the Moon because it orbits us at the same rate as it revolves. However the fact that the Moon's orbit is slightly elliptical means that at times it orbits slightly faster than it revolves and we get to peak around the eastern limb.  At other times the Moon orbits slightly slower than it revolves and we get to see more of the western limb.   In addition, the Moon’s orbital plane is slightly inclined to the Earth’s rotation so that we also get to peak over and under the poles at different times.    All these ways of sneaking a view of the Moons far side are called libration. The net result is that we actually get to see 59% of the Moon's surface. That said, our view of the sides and top and bottom of the Moon as always squashed by some amount of foreshortening.    We only get to see a very small proportion of the Moon without much distortion. Only 24 Apollo astronauts have gotten to see the true shape of most features on the Moon - until now!

Click small images to enlarge

Travelling West from the far side.  Mare Crisium is on the right, Mare Fecunditatis centre right with the bright  crater Langrenus on its eastern shore an an ejecta blanket from crater Petavius to its south.  

Tools on many image manipulating programs let you transform pictures of Moons and planets into virtual globes which you can fly over and capture views that would only otherwise be possible from a spacecraft - exciting or what?

Following an article in January's 'Sky and Telescope' I've been using the 3D Transform rendering feature in Adobe Photoshop to stick my Moon images onto a virtual sphere and then revolve the globe to see what the surface features really looks like. Once you get used to the feature, you can not only fly around the Moon, but swoop down and scan around the alien word as though you are in a spacecraft.   It’s even easy to get lost in the mares and mountains, particularly when their shape is nothing like what the Moon maps show!

 Here I’ve used my latest Moon shots (example above) taken with a Meade LX90 Schmidt Cassegrain and a Nikon D70 digital SLR at prime focus.    The date was December 19^th 2004 and the Moon was at maximum eastern libration. 

   Above an image pasted on the virtual sphere

 Above a glimpse of the far-side

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AAbove after flying over the North pole, we look down at a landscape including the Alpine Valley  

 Flying North, close to the terminator, Mare Nectaris is on the right, below Mare Tranquillitatis.

  For those of us who watched the first Moon voyages it is exciting to think of the participation that computer technology may allow us to experience the second time around.  For those that will be experiencing watching space exploration by people on another world for the first time, using this method on your Moon images can give you a taste of what is to come.