Safe Solar Eclipse Viewing

Fred Espenak

2005 Annular Solar Eclipse Sequence

Part 1: Partial and Annular Eclipses

Introduction

Eclipses of the Sun are fasciating astronomical events that can be safely viewed if certain precautions are taken. But first an important warning. It is NEVER safe to directly view the partial phases of any solar eclipse, or the maximum phases of an annular solar eclipse using the unprotected or naked eye. Even when 99% of the Sun's surface is blocked during the partial phases of a solar eclipse, the remaining crescent is intensely bright and cannot be safely viewed without eye protection.

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Pinhole projection using a kitchen colander. (c)2000 Patricia Espenak

Pinhole Projection

The simplest and most inexpensive method for safely viewing a solar eclipse is called projection. A pinhole or small opening in a piece of cardboard is used to project an image of the eclipsed Sun onto a screen (white piece of cardboard) placed a couple feet behind the pinhole. Making a pinhole projection box to safely watch a solar eclipse is a fun project for kids.

Projected images of the eclipsed Sun can even be seen on the ground by loosely interlacing your fingers and allowing sunlight to pass through small openings between your fingers. The same effect can be seen beneath a leafy tree in the dappled sunlight reaching the ground. Another amusing projection method is to use a kitchen straining spoon or a kitchen colander. Anything with tiny holes can be used to project the partially eclipsed Sun's image: a straw hat, a cheese grater, a lawn chair having a loose weave fabric, etc..

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Binocular projection produces two images of the eclipsed Sun on a white cardboard screen. (c)2000 Fred Espenak

Binocular Projection

Any pair of binoculars can be used to project a pair of images of the eclipsed Sun onto a piece of white cardboard. Just point the binoculars up at the Sun and project their images onto a piece of stiff white cardboard placed 1-2 feet behind them (see photo above). The farther away the screen is from the binoculars, the large the projected image of the Sun. This takes a bit of practice to get the pointing just right so try it out on a sunny day before the eclipse.

You also want to make sure that the binoculars are in focus. Just look through them at some distant scene on the horizon and adjust the focus. WARNING: Never look directly through the binoculars at either the Sun or the partially eclipsed Sun.

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A piece of welder's glass can be used to safely view the eclipsed Sun. (c)2000 Patricia Espenak

Welder's Glass

A widely available filter for safe solar eclipse viewing is a welder's glass. These filters normally protect a welder's eyes from the intensely bright glare of a welding arc. They come in a variety of shades with number 14 being the darkest - be sure to get a number 14 for eclipse viewing. Welder's glass filters are available through welding supply outlets and through retailers on the Internet.

Welder's glass filters (number 14) are safe to use for looking directly at the Sun. The down side is that they give the Sun an unnatural green color cast.

There is a Welder's filter that has a variable density. It changes depending on the brightness of the welding arc (or light source) that it's pointed towards. These variable density filters are NOT SAFE for looking at the Sun.

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Order Safe Eclipse Glasses from American Paper Optics (click here)

Eclipse Glasses

In recent years inexpensive eclipse glasses have become increasingly popular for safely viewing of solar eclipses. They usually consist of specially manufactured filters mounted in a simple cardboard frame. Eclipse glasses allow you to look directly at the eclipsed Sun since the filters safely protect your eyes from any harmful rays. To date three manufacturers have certified that their eclipse glasses and hand-held solar viewers meet the ISO 12312-2 international standard for such products: American Paper Optics, Rainbow Symphony, and Thousand Oaks Optical.

The following are some tips to safely use eclipse glasses.

  • Stand still and cover your eyes with your eclipse glasses or solar viewer before looking up at the bright Sun. After glancing at the Sun, turn away and remove your filter — do not remove it while looking at the Sun.
  • Do not look at the uneclipsed or partially eclipsed Sun through an unfiltered camera, telescope, binoculars, or other optical device. Similarly, do not look at the Sun through a camera, a telescope, binoculars, or any other optical device while using your eclipse glasses or hand-held solar viewer — the concentrated solar rays will damage the filter and enter your eye(s), causing serious injury. Seek expert advice from an astronomer before using a solar filter with a camera, a telescope, binoculars, or any other optical device.
  • If you are within the path of totality, remove your solar filter only when the Moon completely covers the Sun’s bright face and it suddenly gets quite dark. Experience totality, but as soon as the bright Sun begins to reappear, replace your solar viewer to glance at the remaining partial phases.

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A special filter is used to safely view a solar eclipse through a telescope. (c)2016 Fred Espenak

Telescope Filters

Telescopes and binoculars offer the possibility of seeing a magnified view of the eclipse. But this can only be done by using a special filter designed for viewing the Sun. Such filters fit snuggly over the FRONT END of the telescope and permit just a tiny fraction of the Sun's light to pass through.

Solar filters for both telescopes and binoculars are available from a number of companies in the list below.

These filters are essential for safely viewing the PARTIAL phases of an eclipse. But if you want to also use your telescope/binoculars to view the TOTAL phase of the eclipse, the solar filter needs to be quickly and easily removed when TOTALITY begins (see next section). It must be put back on quickly when TOTALITY ends.

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The Sun's corona during the total eclipse of 2016 March 29, (c)2006 Fred Espenak

Part 2: Totality

2017 Total Solar Eclipse Sequence

A total solar eclipse begins and ends with a series of partial eclipse phases typically lasting about an hour before and after the total phase. The methods described in Part 1 above give safe ways of viewing the partial phases.

The total phase of the eclipse (called totality) only last a few minutes and is spectaculary different from the partial phases. The TOTAL phase of a total solar eclipse is completely safe to view with the naked eye. No pinhole projection or filter is needed to safely view Totality. Those methods are only for safely viewing the PARTIAL phases of the eclipse.

The naked eye alone along with a pair of binoculars are the best way to view Totality.

Totality is one of the most awe-inspiring sights in all of nature. For a few brief minutes you are plunged into the dark twilight shadow of the Moon as the Sun's bright disk is completely hidden from view. In its place is the eerie black disk of the Moon silhouetted against the Sun's exquisitely beautiful solar corona.

Visit EclipseWise Solar Eclipses to find information on past and future eclipses of the Sun.

The upcoming total solar eclipse of 2024 April 08 crosses the Mexico, the USA, and Canada giving millions of people the chance to witness this unforgettable event.

Books About Upcoming Eclipses

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Get Eclipsed: A Family Guide to Two North American Eclipses

North America will be the scene for two spectacular eclipses of the Sun. On October 14, 2023, an annular eclipse of the Sun occurs in western USA and Mexico. Six months later, an incomparable total eclipse of the Sun occurs on April 8, 2024. Its 125-mile wide path crosses Mexico, the USA from Texas to Maine, and eastern Canada.

During both of these events, a partial eclipse of the Sun will be visible from virtually all of North America. The last annular eclipse visible from the USA was in 2012. The last total eclipse visible from the USA was in 2017, and the next one to cross the country won't be until 2044. Don't miss the incredible experience of seeing these celestial wonders!

Get Eclipsed is an easy to read, family friendly, inexpensive eclipse guide for the entire family. It tells you everything you need to know about the upcoming annular and total eclipses of the Sun in 2023 and 2024. And it comes with two pairs of special glasses for safely watching the partial eclipse phases and annularity.

For more information visit Get Eclipsed.

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Road Atlas of the Annular Solar Eclipse of 2023

The Road Atlas for the Annular Solar Eclipse of 2023 contains a series of 29 maps of the path of annularity across the USA, Mexico, Central and South America. The large scale (1 inch ≈ 28 miles) shows both major and minor roads, towns and cities, rivers, parks, and mountains.

The annular eclipse phase in which the Moon is completely silhouetted in front of the Sun (known as annularity) will only be seen from within the 115 to 137 mile-wide path of the Moon’s antumbral shadow as it sweeps across the United States (Oregon, California, Idaho, Nevada, Utah, Colorado, Arizona, New Mexico, and Texas), Mexico, Central and South America.

Armed with this atlas and the latest weather forecasts, the road warrior is ready to chase annularity no matter where it takes him/her along the entire path. This mobile strategy offers the highest probability of witnessing the amazing 2023 annular eclipse in clear skies.

For more information visit Road Atlas for the Annular Solar Eclipse of 2023.

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Road Atlas of the Total Solar Eclipse of 2024

The Road Atlas for the Total Solar Eclipse of 2024 contains a comprehensive series of 26 maps of the path of totality across Mexico, the USA and Canada. The large scale (1 inch ≈ 22 miles) shows both major and minor roads, towns and cities, rivers, parks, and mountains.

Although a partial eclipse will be seen from all of North America, the total phase in which the Moon completely covers the Sun (known as totality) will only be seen from within the 120-mile-wide path of the Moon’s umbral shadow as it sweeps across Mexico, the United States (Texas, Oklahoma, Arkansas, Missouri, Tennessee, Kentucky, Illinois, Indiana, Ohio, Michigan, Pennsylvania, New York, Vermont, New Hampshire, and Maine), and Canada (Ontario, Quebec, New Brunswick, Prince Edward Island, Nova Scotia and Newfoundland).

Armed with this atlas and the latest weather forecasts, the road warrior is ready to chase totality no matter where it takes him/her along the entire path. This mobile strategy offers the highest probability of witnessing the spectacular 2024 total eclipse in clear skies.

For more information visit Road Atlas for the Total Solar Eclipse of 2024.

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Eclipse Bulletin: Total Solar Eclipse of 2024 April 08

The Eclipse Bulletin: Total Solar Eclipse of 2024 April 08 is the complementary publication of the 2024 Road Atlas and is the ultimate guide to this highly anticipated event.

Eleven high resolution maps plot the total eclipse track across Mexico, the USA, and Canada. The large map scale (1 inch ≈ 53 miles) shows hundreds of cities and towns in the path, the location of major roads and highways, and the duration of totality with distance from the central line. Local circumstances tables for hundreds cities the USA, Canada, and Mexico provide times of each phase of the eclipse along with the eclipse magnitude, duration and Sun's altitude. A detailed climatological study identifies areas along the eclipse path where the highest probability of favorable weather may be found.

Finally, comprehensive information is presented about solar filters and how to safely observe the eclipse.

For more information visit Eclipse Bulletin: Total Solar Eclipse of 2024 April 08.

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book

Totality - The Great American Eclipses of 2017 and 2024

The Totality - The Great American Eclipses of 2017 and 2024 is a complete guide to the most stunning of celestial sights, total eclipses of the Sun. It focuses on the eclipses of August 21, 2017 and April 8, 2024 that pass across the United States. The U.S. mainland has not experienced a total solar eclipse since 1979. This book provides information, photographs, and illustrations to help understand and safely enjoy all aspects of these eclipses including:

For more information visit Totality - The Great American Eclipses of 2017 and 2024.

Links

Safe Eclipse Viewing



eclipse filters
Safe Solar Eclipse Glasses


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Rainbow Symphony Eclipse Shades


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Thousand Oaks Optical Solar Filters


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Great American Eclipse Store

Eclipse Glasses

Solar Filters for Telescopes and Binoculars

Other Links


Permission is granted to reproduce data from this page when accompanied by an acknowledgment:

"Fred Espenak, www.EclipseWise.com"