Bob Moler's Ephemeris Blog

Ephemeris for Thursday, May 17th.  Today the sun will be up for 14 hours and 54 minutes, setting at 9:06.   The moon, 3 days before new, will rise at 4:44 tomorrow morning.  Tomorrow the sun will rise at 6:10.

Lets talk about a safe viewing method for viewing the sun, for Sunday’s solar eclipse, which starts about 8:19 p.m.  Never look directly at the sun, eclipse or no.  Pinhole projection is a cool method to watch the eclipse without hurting your eyes.  Get a cardboard box, the longer the better.  On one narrow end poke a hole, no larger than an 8th of an inch in diameter.  You can poke several holes an inch apart of varying sizes to get multiple images of the sun of different brightnesses and sharpness.  On the inside of the other end paste a piece of white paper.  Point the holey end at the sun and its image will be projected on the white sheet.  Tomorrow I’ll tell you where to go to get the best view of the eclipse.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

There’s more information on my blog here.

Pinhole projection:

Pinhole Projection of the sun.

Note the brightness of the sun was augmented and moon shadow added to give an idea what the solar image would look like.  The box is 39 inches long.  it gives an image 1/3 of an inch in diameter.