Monday, August 13, 2012

August 13 at Miantonomi's Cave

I just returned from watching an amazing show at Miantonomi's Cave this afternoon, on the date of the  Native American Green Corn Festival.  This show was performed by moving  sun daggers, and I will display the highlights. 
The last entry about this site was Summer solstice.  The cave was full of light at 7:26 and dark at 7:36.  However, the wall behind the large boulder was in sunlight almost until sunset, so I assumed this was the correct solstice marker.  This evening, the 318 degree bearing of the boulder blocked out most of the sun, leaving a small patch visible at 7:16.
Inside the cave, a dance of three sun daggers was in motion.  Here it is at 6:44
The streak of light on the boulder to the far left is coming in through the notch in the bottom of the window. The light makes a larger dagger on the wall below the projecting rock, which touches the center dimple on the wall.  Meanwhile, light from the other window forms a dagger that travels up the wall as the sun sets, with its point touching the large  crack in the wall. The central dagger seems to break up, leaving a spot touching the central dimple. The whole dagger then vanished.  Due to the trees around the site, it is hard to be certain if this was supposed to happen.
At 6:51, the dagger reappeared and entered the area with the dimples. It seems to be a continuation of the ray through the notch in the window base.  Note that the dagger to the right is still  touching the crack, but is higher on the wall.
     7:02 PM
7:07 PM
A tiny dagger crosses the "nose" of the projecting rock in the cave, while the center of the original, center dagger dims, leaving a bright spot to the right at 7:08.
 This vanishes in seconds.
The dagger reappears at 7:11.
It creates this pattern at 7:16
A bright dagger cuts across the projection, and a tiny, bright spot appears again. And then the cave slowly goes dim by 7:20.
It is hard to be certain if this is what the cave's builders saw, since the site is now surrounded by trees, and the sun sets behind a forested hill.  However,  since the  points of the daggers touch dimples, a crack, and a large  projection from the wall,  this site is probably a sophisticated astronomical observatory. It will be very interesting to see the light change in this structure at equinox and winter solstice.

1 comment:

  1. Very nice! I have also noticed that photos can tell me more than I saw at the time. And also that being there at the right time can make all the difference in understanding how features were used. I've become convinced that many rocks were used for multiple observations, so it is not surprising that there would be many indicators at such an important site.
    There is another notable event this time of year - the Perseid Meteor showers. There have been some interesting theories about the significance of the showers to Native Americans and the timing of historical events.