November 15, 2014
image by Maximilian Teodorescu, Dumitrana, Romania
Max continues to experiment with color imaging of the Moon, including creating a standard black and white image and also a color one, based on combining images taken through red, green and blue filters. I have combined them (with a little mismatch, hence the shift in positions) for this LPOD; Max has a similar animated gif of the Copernicus region. but I like the Bullialdus one because the area is less well known. The purpose of alternating between the standard monochrome view and the color version is to emphasize that we overlook differences in surface characteristics in the former because the differences are subtle. Enhanced color brings them out. So let's take a quick tour of what the colors reveal. First, maria and highlands have different colors, the maria are gray, purple and pale green, depending of their compositions, degree of veneering by ejecta, and solar elevation angle. Professional color imagers correct for the Sun angle and shadowing by typically using full Moon illumination. But the geology is easier to interpret when the illumination is lower. The highlands at the bottom right near Arzachel crater are ruddy-orange hued. An orangier-orange surrounds the probably silica-rich volcanic ash at Lassell G and K (center, right side of the image). Max pointed out that the floor of Bullialdus is pinker than surrounding maria, as is some of the ejecta on its rim. Max also noted the dark, almost brown spot that corresponds with the dome at the north end of the Birt Rille. This implies that the dome is made of a slightly different composition than the surrounding maria, or it is younger and not ray-brightened. The rays from Tycho passing west of Bullialdus have a white-tinged with blue purity.
Teleskop Service 115mm F/7 apochromatic refractor + ASI120MM camera + RGB filters.
21st Century Atlas charts 16 & 23.
Yesterday's LPOD: Big Holes
Tomorrow's LPOD: An Image To End All Images (Almost)