Eclipses

A total lunar eclipse occurs when the Moon passes completely into the shadow of the Earth, darkening the lunar surface. (We normally see the Moon by the sunlight it reflects.) Such events only occur during the full Moon phase, when the Moon is opposite the Sun in the sky. During most months, the full Moon passes just above or below Earth’s shadow, and an eclipse does not occur. But when the Sun, Earth, and Moon are aligned in the same plane in space, the full Moon passes into our shadow and we see a lunar eclipse. These precise alignments bring us the possibility of lunar eclipses roughly every six months. For a partial lunar eclipse, the Moon does not completely pass into the darkest part of Earth’s shadow (the umbra), and so only part of the Moon appears significantly darkened. All total lunar eclipses have partial phases before and after totality. Occasionally, the Moon passes just outside the umbra, and a slight fading of part of the Moon occurs. This is a penumbral lunar eclipse, in which Earth is blocking some of the sunlight from reaching the Moon, but no part of the lunar surface sees the sunlight totally blocked.

Observatory host Tim Martin has produced a video describing lunar eclipses.

The NEXT good eclipse for our area occurs on 2022 May 15.

By around 10:15 p.m. Sunday, 15 May (all times noted are EDT), it will be apparent that something is happening to the moon. The bright full moon will be in the southeastern sky and show a slight darkening at its eastern edge (lower left). We see the moon move gradually west to east against the background stars as it shifts along its orbit – that's why it rises later on successive nights. But the rotation of Earth causes the moon to move higher in the sky in the evening as it heads westward across the dome of the sky. So as the moon shifts across the sky during the night, it will also creep eastward across Earth's shadow. This will look like a darkening of the moon from left to right the night passes.

Partial eclipse begins at 10:27 p.m., as the deep shadow starts to eat away at the orb of the moon. Over the next hour or so, the moon will slowly slip into darkness, revealing constellations that were washed out by the bright moonlight earlier in the evening. The moon will be located in the constellation Libra on the night of the eclipse.

As totality approaches (beginning at 11:29 p.m.), it will become apparent that the moon is not fading to complete invisibility – the darkened moon will likely shine with a reddish color. The intensity of this light varies from eclipse to eclipse, and it is due to the combined glow of all the sunsets and sunrises around the earth filtering through our atmosphere to reach the moon. Each eclipse is slightly different, depending on the path of the moon through our shadow and the condition of our atmosphere. (More particles in the upper atmosphere, due to, for example, volcanic eruptions, will block more light from passing.) So, pay attention to the moon's color during the eclipse. Is it actually blood red? Or is it brick red, basketball orange, or dull gray?  Use this resource from Sky &Telescope outlines the Danjon Scale for rating lunar eclipse color. Note that there might be some variation of shading as the event progresses. It’s best to make your color judgement a bit after midnight, when the moon is closest to the center of the shadow.

Mid-eclipse occurs 12:11 a.m. and totality ends by 12:54 a.m. After this the moon will slowly work its way out of the shadow, and the night will brighten again. The post-totality partial phase ends at 1:55 a.m.

Be sure you are looking on the right night! Many sources will list the eclipse occurring 16 May, but we will see it beginning late on the 15^th and continuing after midnight on the morning of the 16^th. The date variation occurs because astronomers use a common time reference for reporting time-sensitive events, Universal Time (UT). UT is essentially the same as Greenwich Mean Time (GMT). Mid-eclipse is after midnight in Greenwich that night, so the official designation is the 16^th.  In the Triad, under Daylight Saving Time, we’ll be four hours behind UT, so we’ll see the eclipse start on the evening of the 15^th.

We plan to hold an observing session on the grounds of Cline Observatory during this eclipse, weather permitting. The session will begin around 10 p.m. and will wrap up after totality ends, around 1 a.m. The session will be dedicated to general sky/eclipse-watching, and we'll provide views of the moon and other objects through our various telescopes. There's not a lot of seating in the observatory area, so if you plan to come out to experience the event, you might want to bring a lawn chair. But remember, you don't have to join us to see the eclipse – make sure you take a look at it wherever you are!

• NASA eclipse resource sheet for the 2022 May 16 Eclipse
• timeanddate.com page for the 2022 May 15-16 Eclipse

NOTE: A telescope is NOT needed to view this or any other lunar eclipse, so if you don’t want to venture out late to join our session, you can always watch by stepping outside and looking up at the moon, wherever you are.

Weather permitting, Cline Observatory will be open for public viewing the night of the eclipse. General details will be posted here as the event approaches. In the days before the eclipse, updates will be posted at the observatory’s Twitter page, @gtccastro.

But a trip to an observatory is not necessary to enjoy an eclipse. Lunar eclipses can be viewed from any location where the Moon can be seen – optical aid is not required. If you can see the Moon, then you can observe the eclipse, no matter what your location. Telescopes or binoculars will enhance the view, but are not necessary.

For more information on lunar eclipses occurring this period, see NASA Lunar Eclipse Page and Catalog of Lunar Eclipses: 2001 to 2100.

As with lunar eclipses, for solar eclipses to occur, the sun, moon, and earth must be directly in line and on the same plane in space. For all variations of solar eclipses, the moon must be in the new phase, with the arrangement of the bodies being sun-moon-earth. A total solar eclipse occurs when the moon appears to completely cover the sun. An annular solar eclipse occurs when the moon appears too small to completely cover the sun, and thus the sun is not completely blocked, with an exposed ring of bright sunlight around the dark moon. (This can happen because the moon's orbit is not perfectly circular, so sometimes it is a bit closer to, or farther from, earth than normal.) For a partial solar eclipse, the moon is not situated directly between the sun and the observer, and thus blocks only part of the sun.

A total solar eclipse occurs when the moon appears to completely cover the sun. An annular solar eclipse occurs when the moon appears too small to completely cover the sun, and thus the sun is not completely blocked, with an exposed ring of bright sunlight around the dark moon. For a partial solar eclipse, the moon is not situated directly between the sun and the observer, and thus blocks only part of the sun. For all of these types of eclipse, the moon must be in the new phase, with the arrangement of the bodies being sun-moon-earth. Solar eclipses usually happen roughly six months apart, and because of their timing, can only be seen from certain parts of earth. Upcoming solar eclipses visible from our area are listed in the table below

Note: the 2026 August 12 partial solar eclipse is not visible in the Triad, but parts of N.C. to our northeast and east will see it.

For more information on solar eclipses occurring this period, see the NASA Catalog of Solar Eclipses: 2001 to 2100. Other useful resources are the Great American Eclipse page, TimeandDate.com’s eclipse list and Xavier Jubier’s Interactive Eclipse Maps.

It is dangerous to your eyesight to stare at the sun, so here are a few tips if you want to try to observe a solar eclipse:

• Make a pinhole projector – use a pin to poke a hole in a piece of cardboard, orient that hole toward the sun, and use a second white card or piece of paper onto which you can project an image of the sun. This JPL page shows you how to make a pinhole camera for projection of the image of the eclipsed sun.
• Watch the full eclipse online – for each major eclipse there are usually a few sites offering live streams of the event. TimeandDate.com has a regular eclipse livestream page.
• Safe solar viewers are available from a number of sources – just do a web search with the terms, eclipse shades, eclipse glasses, or solar viewers. 
• A shade 14 welder's lens is safe for viewing the sun, but regular shades (e.g. 10) are still too bright, though they may be acceptable for quick looks if the sun is low on the horizon.
• Don't try to improvise on your own filter. See these resources from Fred Espenak and the American Astronomical Society for information on safe solar viewers.
• Never try to look directly at the sun through unfiltered (or inappropriately filtered) binoculars, telescopes, or telephoto lenses.