Help me find this feature from Epic Moon
Posted 29 June 2013 - 12:30 PM
I've been reading William Sheehan and Thomas Dobbins' work Epic Moon over the past few days. As I remember from Sheehan's previous works, I enjoy how he and his co-authors can make astronomical history interesting and engaging.
Like many I am sure, one of the things I really enjoy about reading astronomical history is putting myself in the observer's shoes and wondering if I, with my comparable modest equipment, would make the same conclusions such as changing phenomena or even life on the moon.
I am trying to find a feature described in Chapter 7: The Moon's White Cities. As described on page 81, Franz von Paula Gruithuisen in July of 1822 detected (in his mind) a formation that was "a colossal structure, not dissimilar to one of our cities" on the moon using his 2.4" refractor.
Gruithuisen's almost Percival-Lowell-esque sketches show a structure (that he called the Wallwerk) of walls and ramparts that he believed to be massive monuments constructed by the Selenites.
I want to try to repeat Gruithuisen's observations at last quarter and see if I can imagine myself being fooled into thinking such a structure exists. The problem is, at least from the Epic Moon text, I can't quite figure out where the structure is.
The text gives this vague location: "In the early morning hours of July 12, 1822, Gruithuisen turned his 2.4-inch refractor toward the Moon, then at Last Quarter, with the terminator crossing over the western rim of Clavius in the one direction an Newton in the other. (Schroeter's 'Newton,' not the formation later designated by the name; it consisted of the part of Mare Imbrium enclosed between the Alps and Montes Teneriffe. " And furthermore: "In the gloomy region to the southeast, where the mountains cast long dusky spires of shadow across the plains, he was astonished to find a collection of 'dark ramparts' whose arrangement impressed him as more orderly than haphazard."
Looking at my various atlases, I really can't seem to find the location at which Gruithuisen was looking.
Can anyone help me pin it down?
Posted 29 June 2013 - 12:36 PM
I wrote the message above while on a 9 hour plane flight, intending to search the web before I posted it. Well, I just did a quick search and Wikipedia reveals, "To the north of Schröter, beginning with the satellite crater Schröter W, is a region of irregular terrain. This area includes an array of linear dark surface markings that appear to criss-cross. In the 19th century, Franz von Gruithuisen is noted for claiming that this area contained a lunar city, based on his observations using a small refracting telescope. This inference was greeted with considerable skepticism by astronomers at the time, and, indeed, subsequent observations with more powerful instruments demonstrated that this was merely a natural feature."
Posted 29 June 2013 - 12:49 PM
Posted 02 July 2013 - 11:16 AM
The area I found that I thought might be his "Wallwerk" was located 1st by locating the crater pair Pallas and Murchison, near the center of the moon. Then extending a line between their centers toward the West (i.e. toward Conpernicus), until it intersects a hypothetical line from the decayed crater Schroter straight up to the North. The intersection of these 2 hypothetical lines is the approximate position of this feature. I have seen what might seem like slanted cliffs. They are only visible when that area is on the terminator however. so it is not easy to locate and a small feature when you do.
I suppose a hundred years ago through a 2.4" refractor, it might look like a city, if you already expecting to find such a thing.
Posted 03 July 2013 - 11:30 AM
Posted 03 July 2013 - 11:50 AM