Chapter News

I've always been amazed by the beautiful star trail photos I see professional photographers make.  Apprarently, it's really not that difficult to take these, and there are tons of websites that will walk you through the process.  This one is a "stacked" image that combines 30, 2 min exposures at f/4 and iso400.  Camera was a Canon 70D with a 18-55mm lens set to 24mm.  Total photo time - 60 minutes (1hr).  Based on this, I would expect that each of the star trails, which are caused by Earth's rotation, would trace out an arc of 1/24th of a full 360 degree circle, or about 15 degrees or arc, with Polaris at the center.  Notice the pulsed light from an airplane that flew over at some point during the hour.

Aside from "stacking" the images with free software available online, the picture was not adjusted or enhanced in any other major way.  More to come once I figure out how to work the camera and intervalometer better!

Picture taken from 10:55pm-11:55pm looking due north at approximate altitude of 40 degrees, from my back yard in Pipersville, PA.


2015 PAESTA Earth Science Week Essay Contest Winners Announced

Earth Science Week

For Earth Science Week 2015, PAESTA held an essay contest that challenged K-12 students in Pennsylvania to write an essay with the following theme: Why Earth Science Matters in Pennsylvania. We are thrilled to announce the three winning essays, all written by students in Sandy Grajewski's classroom at Conrad Weiser High School in Robesonia, PA.

Succession is causing Hickory Run State Park's Boulder Field to shrink, albeit quite slowly, as trees take root amongst the rocks.  The field, which is the size of ten football fields, is believed to have been formed during the last ice age.

Trees Encroaching on Boulder Field