On August 21, a total solar eclipse will cross over North America, from coast to coast. What makes this more of a rare event, the path of totality will be entirely over continental United States. The narrow band will stretch from Salem, OR to Charleston, SC. A partial eclipse will be seen outside the band of totality. How much of a partial eclipse will be seen by those outside the band of totality is determined by how close they are to the band.
In Colorado, for example, the partial eclipse will range from 85% (NM border) to 95% (WYO border). The last total eclipse through the western states was in October 1978. At that time, the partial eclipse was around 85%. In terms of light, it was similar to what one would expect at the beginning of evening twilight with longer shadows. With the coming eclipse, observers in Colorado should expect the same. If it is overcast, it should be darker – with the level of darkness determined by the thickness of the overcast.
Seeing with my eyes –
Under any circumstance, do not observe the sun without proper eye protection. If you choose to use eclipse glasses or viewers, it must be ISO-12312-2 compliant (meaning it meets the minimum safety standard to directly view the sun). The American Astronomical Society (AAS) has developed list of reputable vendors, which can be found here.
The low cost (free), DIY approach is to make a pinhole viewer, consisting of a cardboard box (smaller the better) and an unused piece of bright white, multipurpose paper. Make a pinhole in the cardboard box, the white piece of paper is the projection screen. Before the eclipse, practice lining up the cardboard box over the paper. What you are looking for is the brightest amount of light coming through the pinhole.
DIY: pinhole eclipse viewer parts with spatial analysis test
If you have a telescope, there is a good chance it came with a sun filter for your eyepiece. Line up your telescope without using your finderscope, which is fairly easy. With the sun filter in your eyepiece, line up your telescope before the eclipse begins. If your telescope came with a solar projection screen instead of a filter, it is the same process like using a pinhole viewer.
The super-safe way of following the eclipse is to watch NASA, online or their TV channel (DISH Network and DirecTV). You’ll also receive a science lesson on the side.
Photographing the solar eclipse –
Photographs of a solar eclipse cannot be beat. If that is your plan, the plan should be nearly complete in terms of equipment and practice. If not, Canon USA has assembled a reference guide to photograph the eclipse – from an introduction to eclipse photography to equipment to site preparation.
Eclipse Extra: Tonight – Partial Lunar Eclipse –
Whenever the Earth, the sun and moon line up for an eclipse, on occasion, the eclipse will come as a pair. Tonight, during the full moon phase, a partial lunar eclipse will occur. The partial eclipse will come around sunset for those in eastern Europe and Africa, and before sunrise on August 8th in the Far East and Australia. In North America, no partial lunar eclipse will be seen.
Online Resources –
- NASA – Eclipse 2017
- Sky and Telescope Magazine
- Astronomy Magazine
- Space.com: Total Solar Eclipse 2017
- Canon USA: A Total Guide To Totality
- Nikon USA: Astrophotography