Rolled Boulders on the Moon

While looking for the Apollo 16 landing site on Google Maps I came across this field of boulders which have rolled down a slope leaving curved tracks behind them.  The largest of the rolled boulders seem to be 1 to 2 metres across.  You can find them at https://www.google.co.uk/maps/space/moon/@-9.1114261,15.4352907,1547m/data=!3m1!1e3.  If you enter 3D view (only available if you  are signed in to Google) you will see that the high ground is in the bottom right.

Now I come to think about it, the fact that the tracks are intermittent and curved makes me think the boulders weren't rolling but bouncing, having been ejected by an impact out of picture to the lower left.  This would explain why in the right-most track the gap between the bounces decreases and the direction of the track converges on the downward direction of the slope as the boulder loses momentum with each bounce.

Back in the late 1960's and early 1970's certain amateur astronomers would order prints from NASA of the Orbiter and Apollo photos of the Lunar surface and then subject them to microscopic scrutiny looking for interesting features like this (but I suspect they were really looking for alien artefacts).

Venus

The planet Venus rising at about 6am yesterday morning.

Annular Solar Eclipse

While looking at Google Maps I happened to notice this black spot over the south Atlantic.  I immediately suspected that this must be Google being clever and showing a solar eclipse and, sure enough, Wikipedia shows that there is an annular solar eclipse in progress in that area at this very moment: https://en.wikipedia.org/wiki/Solar_eclipse#/media/File:Central_eclipses_2001-2020.png

Venus and the Moon

From last Tuesday morning: planet Venus and the crescent Moon in the pre-dawn sky.  Mercury should have been visible a few degrees to the lower left of Venus, but I did not notice it at the time and so did not include it in the image.

Photo taken in Reading, UK, on 2012-12-11.

Mira Ceti

Last night I woke in the early hours and looked out through the window, up at the clear sky.  The pulsating star Mira Ceti was brighter than I ever remember seeing it back when I was an active observer of variable stars.  I judged it be slightly brighter than Alpha Ceti (mag. 2.5) at about mag. 2.4.  A few nights ago it had been clearly fainter than Alpha at about mag. 2.7.  Maximum is predicted to be in the next week or two, so it will be interesting to see if it continues brightening to near the historical record maximum of mag. 1.7.

The above chart is from Ball's Popular Guide to the Heavens (1905).  Mira Ceti is the small star to the left of the label 'o = Mira (var)'.  At its current brightness it can be compared with the following stars:

• Alpha Arietis (mag 2.0), the bright star near the top edge
• Alpha Ceti (mag 2.5), the bright star near the left edge
• Beta Arietis (mag 2.7), near Alpha Arietis
• Gamma Ceti (mag 3.5), near Alpha Ceti
• Alpha Piscium (mag 3.8), the 3-pronged star just right of centre
• Delta Ceti (mag 4.1), midway between Alpha Ceti and Mira