This Sunday, May 20, there’s an annular eclipse — a ring-around-the-moon not-quite-a-total eclipse.
I’m traveling to an area where it’s as total as possible this weekend (the SW corner of Utah), but here’s instructions for
how when to view it where you are. The Exploratorium has a how to view it post.
You need to know three things:
- your lat-long coordinates
- your elevation (altitude) in meters
- what time zone you’re in
Convert Street Address (Location) to Lat-Long — Geocoder.us will convert a street address into lat-long info.
For an example, I’ve put in the address of the Jet Propulsion Laboratory, and gotten the lat-long coordinates. I looked up the elevation for the city that JPL is located, and decided to average the high and low elevations to 500 m.
In the first section, I entered those JPL coordinates as follows:
Here is the result after clicking the 20th century button
Compare that to the result for Cedar City, Utah, which does have annularity to the eclipse. (The eclipse is listed as A — annular, and there are additional details for times of entering annularity)
The key to the table says that for the eclipse magnitude it’s a fraction of the sun’s diameter that’s obscured by the moon. For annular eclipses the magnitude is less than 1.0
I learned from the Planetary Society’s night guide for Summer 2012 that it’s possible to get Eclipse viewing glasses, and so I made a trip out to the store in the San Fernando Valley where they sell them. Here’s my stash for the Family Eclipse Viewing partipants. Oh, and I got a special filter to use on the telescope.
IMPORTANT! If you do not have this special optical filters that make it safe to look at the sun, use the pinhole camera method of viewing as described in the Exploratorium article.
Last, but not least, it’s important that you have an unobscured view of the sun. There was a lovely annular eclipse in the early 1990s, and I didn’t see it, even though I was in the right place. A group of us stood at the top of Mount Wilson and cursed the clouds.
The outlook for our viewing location looks perfect. Sunny, no cloud cover.