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NASA’s Astronomy Picture of the Day for Nov. 1, 2026, features a collection of differently colored full Moons photographed by Marcella Giulia Pace from locations across Italy over 10 years. NASA says red and yellow hues often result from viewing the Moon through more atmosphere near the horizon; the cause of the purple appearance remains unclear.
NASA’s Astronomy Picture of the Day for Nov. 1, 2026, features a collection of full Moons in apparent shades of red, yellow, blue and purple, photographed by Marcella Giulia Pace from different locations across Italy over a 10-year period. The accompanying explanation says the colors seen from Earth can reflect how the Moon’s light passes through the atmosphere, while the cause of the purple Moon in the collection is not clear.
The image brings together observations made over a decade rather than showing one Moon changing color during a single night. NASA’s explanation says the Moon, viewed outside Earth’s atmosphere, appears brown-tinged gray because it shines by reflected sunlight. The colors in the featured collection are apparent colors observed from Earth, where the atmosphere can affect the light reaching a viewer or camera.
NASA says a red or yellow Moon usually appears that way when it is near the horizon. Its light then travels through a longer path in Earth’s atmosphere, where some blue light is scattered away. The explanation adds that fine dust can sometimes be present along that path. A blue Moon is described as rarer and may indicate an atmosphere carrying larger dust particles.
The final image in the collection shows the total lunar eclipse of July 2018. NASA explains that the Moon appeared faint red while inside Earth’s shadow because sunlight was refracted through air around Earth. The APOD entry credits the images to Pace and lists Robert Nemiroff, Jerry Bonnell, Cecilia Chirenti and Keighley Rockcliffe as authors and editors.
Why Moonlight Changes Color
The image gives readers a visual record of how the Moon’s appearance can vary with viewing conditions on Earth, not just with changes on the lunar surface. The explanation distinguishes the Moon’s usual appearance beyond the atmosphere from colors that can arise as its reflected sunlight travels through air, dust and other atmospheric particles.
That distinction matters when interpreting a striking Moon photograph. Red or yellow near the horizon has a familiar atmospheric explanation in NASA’s account, while a blue appearance is rarer and is linked there to larger particles in the atmosphere. The collection also includes an eclipse, when the Moon’s faint red color has a different explanation: sunlight bent through Earth’s atmosphere reaches the shadowed Moon.
NASA does not present every hue as settled or attributable to one cause. In particular, the purple appearance remains unexplained in the entry. The image is therefore both a record of observed color and a reminder that an appearance alone may not identify the exact atmospheric conditions behind it.
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A Decade of Italian Moon Photos
The Nov. 1 entry is part of NASA’s Astronomy Picture of the Day, a daily feature that presents an image or photograph of the cosmos with a brief explanation written by a professional astronomer. The page is credited as a service of the Astrophysics Science Division at NASA’s Goddard Space Flight Center, NASA Science Activation and Michigan Technological University.
For this entry, Pace assembled full-Moon images recorded over 10 years in different parts of Italy. The source does not provide the dates, locations or exposure details for each individual photograph, so the collection should not be read as a controlled comparison of atmospheric conditions. NASA’s explanation instead offers general descriptions of possible causes for several apparent colors and separately identifies the 2018 eclipse image.
Purple Hue Has No Confirmed Cause
NASA’s explanation does not identify the specific atmospheric conditions, dates or locations responsible for each color in Pace’s collection. It describes general possible causes: a longer path through the atmosphere for red or yellow light, and larger atmospheric dust particles as a possible indicator when the Moon appears blue.
The source says the purple Moon’s cause is unclear and may involve several effects. It does not specify which effects those might be or report measurements that would establish a cause. The entry also provides no technical details about the photographs, so it is not possible from the supplied information to assess how camera settings or image processing contributed to their appearance.
The APOD Feature Continues Daily
NASA’s page lists the next Astronomy Picture of the Day as “open space.” The source offers no further announcement about the Moon-color collection, additional image data or a planned follow-up explaining the purple hue. For now, the published explanation presents the atmospheric effects as general interpretations and leaves that particular color unresolved.
Key Questions
What is NASA’s Nov. 1, 2026, Astronomy Picture of the Day?
It is a collection of apparent colors of the full Moon, documented by astrophotographer Marcella Giulia Pace over 10 years from different locations across Italy.
Why can the Moon look red or yellow?
NASA says those colors usually occur when the Moon is near the horizon. Its light travels through a longer path in Earth’s atmosphere, where some blue light is scattered away; fine dust may also be present.
What can a blue Moon indicate in this explanation?
NASA describes a blue-colored Moon as rarer and says it can indicate an atmosphere carrying larger dust particles. The entry does not identify the specific conditions for the blue image in the collection.
Why is one Moon in the collection red during an eclipse?
The final image shows the total lunar eclipse of July 2018. NASA says the Moon appeared faint red because sunlight was refracted through air around Earth while the Moon was in Earth’s shadow.
Does NASA know what caused the purple Moon?
No. The APOD explanation says its cause is unclear and may reflect a combination of effects. It does not name or confirm those effects.
Source: science.nasa.gov
