Lunar Explorations

The search for change on the moon – a search in vain.

People have often fancied that the moon was an active world, even harboring life. Many observers, both professional and amateur, have believed that they stumbled onto visual evidence suggesting changes occurring on the moon, perhaps from vulcanism, perhaps due to life.

All dates are set at 0 hours UTC.


Feature: Observation Notes:  Click on the image to print/view PDF
1. Between the craters Walther and Gauricus. Best seen: April 19 (evening); and April 
30 (morning), 2024.

2. Gassendi, crater. Best seen: April 3 & 4 (morning); and April 21 (evening), 2024.
1. 1671. Several times, Giovanni Domenico Cassini thought he saw a misty 
formation, perhaps a cloud.

2. 1776. English astronomer William Herschel imagined that the shading variations 
on the crater floor were caused by the changing shadows of a vast forest containing 
trees that were several times taller than those on Earth.

3. Hevelius, crater. Best seen: April 5 & 6 (morning); and April 23 (evening), 2024.
4. Alhazen, crater. Best seen: April 12 & 24 (evening), 2024.
3. 1787. German observer Johann Hieronymous Schroeter suspected that a 
volcano recently formed in the Hevelius crater.

4. 1791. Schroeter saw changes in the definition of the crater that he thought were 
possibly due to mist or vegetation.

5. Two-thirds of the distance from Eratosthenes to Schroeter in Sinus Aestruum.
Best seen: April 1 (morning); and April 19 (evening), 2024.

6. Sinus Iridum. Best seen: April 2 & 3 (morning); and April 20 & 21 (evening), 2024.
5. 1822. Bavarian observer Franz von Paula Gruithusien saw the layout of a great 
lunar city, Wallwerk.

6. 1837. During the Great Moon Hoax, newspaper writer Richard Adams Locke 
reported that rational beings were said to live there.

7. Messier and Messier A, craters. Best seen: April 13 & 14 (evening); and April 26 
(morning), 2024.

8. Cichus, crater in Mare Nubium. Best seen: April 2 (morning), and April 19 & 20 
(evening), 2024.

7. 1855. Some observers, led by the renowned observer the Reverend Thomas 
William Webb, saw a change in their respective configurations.

8. 1859. Rev. Webb thought it had enlarged its diameter since Schroeter observed it 
seventy years earlier.

9. Fracastorius, crater. Best seen: April 15 (evening); April 27 (morning), 2024.

10. Plato, crater. Best seen: April 1 & 30 (morning); April 19 (evening), 2024.

9. Circa 1870. French astronomer Jean Chacornac. Fragmentary walls believed to 
have formed from oceanic erosion.

10. 1869. English amateur astronomer William Radcliffe Birt encouraged his 
colleagues to closely examine the flat floor of Plato for any signs of change.

11. Linné, small crater. Best seen: April 17 (evening); April 29 (morning), 2024.

12. Hyginus N, near crater Hyginus along Rima Hyginus. Best seen: April 17 (evening); 
April 29 (morning), 2024
11. 1866. Johann Frederich Julius Schmidt, followed by others, thought that crater 
Linné had been damaged or transformed.

12. 1877. Hermann Klein, Director of the Cologne Observatory, found a dark patch 
near Hyginus crater, one that hadn’t been visible in earlier observations.

13. Theophilus, crater. Best seen: April 15 & 16 (evening); April 28 (morning), 2024.

14. Plinius, crater. Best seen: April 16 (evening); April 28 (morning), 2024.
13. Circa 1900. Suspected snowstorms on the central peak were glimpsed by 
William Henry Pickering.

14. Circa 1900. Suspected snowstorms on the central peak were glimpsed by 
William Pickering.

15. Alphonsus, crater. Best seen: April 1 & 30 (morning); April 18 (evening), 2024.

16.  Bullialdus, crater. Best seen: April 2 (morning); April 19 & 20 (evening), 2024.
15. Circa 1900. Pickering attributed indistinct, dark areas on the crater floor to 
changing vegetation. He believed that he also saw snowstorms on its central peak.

16. Circa 1900. Suspected snowstorms on the central peak were glimpsed by 
William Pickering

17. Mons Pico, lone mountain. Best seen: April 1 & 30 (morning); April 19 (evening), 

18. Montes Recti, straight mountain range. Best seen: April 1 (morning); April 20 
(evening), 2024.

17. Circa 1900. Suspected snowstorms on the peak of this isolated mountain were 
glimpsed by William Pickering.

18. Circa 1900. Some observers saw it as an artificial construct. Suspected 
snowstorms were glimpsed by William Pickering.

19. Eratosthenes, crater. Best seen: April 1 (morning); April 18 & 19 (evening), 2024.

20. O’Neill’s Bridge, mistaken formation. Best seen: April 13 & 14 (evening); April 26 
(morning), 2024.

19. 1924. William Pickering interpreted shading changes on the crater floor as being 
due to vegetation growth and migrating swarms of insects.

20. 1953. New York Herald Tribune science editor John J. O’Neill reported that he 
observed a twelve mile long natural bridge at the edge of Mare Crisium near the 
intersection of Promontorium Olivium and Promontrium Lavinium, just east of Proclus 
crater. Some believed it to be artificial, others saw nothing. 


Moore, Patrick, Guide to the Moon, 1953, Eyre and Spottiswoode Publishers

Webb, Rv. TW, 1962, Celestial Objects for Common Telescopes, 6th revision, Dover

Sheehan, William; Dobbins, Thomas, 2001, Epic Moon, Willman Bell

Wood, Charles A., The Modern Moon, 2003, Sky Publishing

Rukl, Antonin, Field Map of the Moon, 2005, Sky Publishing

Birren, Peter, Objects in the Heavens, 2011, Birren Design