The Partial Solar Eclipse of 08 April 2024

The Partial Solar Eclipse of
Monday, April 8th, 2024

This is the last solar eclipse visible from Idaho until January 14th, 2029.  While this eclipse will be total along a narrow path from Western Mexico to Canada's Maritime Provinces, in Southern Idaho it will be partial, with the sun only 40% covered at mid-eclipse.

Path of totality of the April 08, 2024 solar eclipse
Map by Fred Espenak,

Follow these solar eclipse viewing safety rules to avoid permanent eye damage:

  • Proper filters (such as those available very inexpensively from the Herrett Center Store) MUST be used to view this eclipse safely!  Such filters are designed to go directly over the eyes; do not use them between your eye and any form of optical aid, like binoculars or a telescope.
  • Supervise small children who may be tempted to stare at the sun during the eclipse, since their normal instinct to stop looking due to discomfort will be diminished due to the reduced brightness (although the potential for permanent eye damage is not diminished).
  • Welding glass must be rated at #14 or higher to prevent permanent eye damage.  Stacking lower-rated welding glass (e.g. a #10 and a #4) does NOT provide equivalent protection as a #14!  Just because you don't experience pain doesn't mean your eyes are not being damaged!
  • If you use an electronically-darkening welding helmet, be sure it is rated to provide #14 or higher equivalent protection.
  • Sunglasses are completely inadequate protection, regardless of any lack of perceived discomfort.
  • Do not use solar filters which attach to a telescope's eyepiece.  (In fact, if you have one of these eyepiece solar filters, throw it away—it's not safe!)  The solar heat concentrated on them can cause them to crack suddenly and allow damaging light to reach the eye.  The only safe solar filters for telescopes and binoculars filter the sunlight before it enters the optics, not after!
  • Completely exposed and properly developed black-and-white negative film may be used as a filter (but seriously, who has any of that around any more?)
  • Make a simple pinhole projector by poking a small hole in a piece of cardboard, and casting the eclipsed sun's image onto another piece of cardboard (white works best.  Or, you can make a better version by following these plans (Microsoft Word document).

April 08, 2024 partial solar eclipse

Relative positions of the sun and moon (l) and actual appearance of the sun through a solar filter (r) at mid-eclipse, as seen from Twin Falls, Idaho, USA.

Eclipse timeline (all times listed are in Mountain Daylight Time (UT-6 hrs.) for Twin Falls, Idaho, USA), calculated by the Solar Eclipse Calculator & Diagram by Xavier Jubier:

  • 11:15:00 AM — Centennial Observatory opens for telescope viewing, weather permitting.
  • 11:28:39 AM — First contact.   A tiny, growing "bite" begins to appear on the lower right quadrant of the sun as the moon begins its excursion across the solar disk.
  • 12:31:32 PM — Mid-eclipse.  The moon reaches its maximum coverage of the solar disk (40%); the sun appears as a fat crescent with downward-pointing "horns" (see diagram, above).
  • 01:36:29 PM — Last contact  The last, tiny "bite" of the moon's silhouette disappears from the left edge of the solar disk, signaling the eclipse's end.
  • 01:45:00 PM — Observatory closes.