30 second exposure of the Milky Way from the outer cape
This image was acquired with a simple digital camera placed lens-up on a driveway. I set the camera to ‘manual’ so I could control the shutter speed, which I set to 30 seconds. I also set the ISO to 800 so I could pick up the faint stars. When I imported the image to my computer it didn’t look like much, but there were lots of stars hidden in the details. I brought these out with the exposure slider, and this is the result. The dim glow in the background is the Milky Way, the hundreds of stars that are visible are nearby, in between us and the center of the galaxy. If I attempted this near a city like Boston, the whole sky would be a diffuse glow of scattered streetlights.
Parhelic arcs - around the full Moon!
We often see these on either side of the Sun here in the winter, but I have never seen these caused by moonlight. In order to pick up the faint colors in the arcs I had to completely overexpose the full moon, which is why none of the details are visible on its face. I stabilized the camera by placing it on the porch railing and shot for several seconds.
The arcs are part of a family of geometric patterns formed when sun or moonlight gets refracted by ice crystals in our upper atmosphere. This is a neat reminder that while it may be warm down here on Earths surface in the summertime, that it is always cold in the upper atmosphere! To learn more about atmospheric optics, check out this great page: http://www.atoptics.co.uk/
