We had a perfectly clear sky last night. I set up my telescope in the field below my house, then ate dinner as dusk settled. I use a Celestron reflecting scope, which I purchased almost fifteen years ago, while living in Texas. At the time, I would drive to the hill country east of Austin, to escape the city lights. Here, I just walk outside.
The scope has an eight-inch diameter. A telescope’s diameter (or “aperture,” to use the correct term) determines its light-gathering ability. A larger aperture collects more light and thus can view more faint, distant objects. On a clear dark night, an eight-inch aperture does a good job of finding many of the famous deep space galaxies and nebulae.
Last night’s target was the moon, an object so bright and close that one doesn’t even need a telescope. Nonetheless, the scope gave a breathtaking view.
The moon in this view is eight days old (eight days since the new moon), and is called a “waxing gibbous moon.” The eighth day is an especially good time for viewing because the massive crater Copernicus has just emerged from shadow. (Seen above, Copernicus is the crater near the center of the moon.) As objects enter the light, the sun illuminates them at a sharp angle, and they appear in relief. Compare, for instance, the flat appearance of the fully-illuminated moonscape to the left, against the variegated lands to the right.
In the case of Copernicus, we see massive walls enclosing a deep central crater and even a hint of central mountains within the crater. Here is a close-up view, in which the central mountains are clearly seen:
Copernicus is approximately 60 miles in diameter and 12,600 feet deep. The mountains inside are a little less than one mile high. We believe the crater formed about 800 million years ago.
Here again is the full view, with Copernicus near the right-hand margin. If you move from Copernicus in a straight line to the left, about two-thirds toward the edge of the moon, you arrive at a broad flat plain, with similar broad dark expanses above and below it. This the Sea of Tranquility, where the moon landings occurred. Above it is the Sea of Serenity and below the Sea of Fecundity.
Near the top of the moon, slightly farther into the light than Copernicus, we see the crater Plato. Plato measures about 66 miles across and 8000 feet deep. Here is a closer view (Plato is the crater near the photo’s center).
Plato gives a spacious, calm appearance, perhaps because of its location within a broad range of hills and mountains. I have a guidebook from the 1960s in which the author imagines “that the shadow band, cast by the mountains along [Plato’s] east wall, exhibits a fine structure of humps and narrow spires like the skyline of a small town with several churches.” Look at the shadow line. You can almost see it!
Finally, here are the rugged mountains and craters at the moon’s south edge. If Plato hosts a contented church-going village, then these southern extremes must be the lunar wrecking yard, surely an inhospitable land.
(A note about the pictures: Because of the optics of my telescope, all of the images are reversed from nature. They are mirror-images of the actual moon; while north-south directions remain accurate, the east-west axis is reversed. The pictures were taken through my telescope by holding an iPhone in front of the ocular. While it is amazing that this system works so well, I hope to buy an actual camera, which can be mounted on the telescope, and this will greatly improve the image quality.)