L22 - Aristarchus Plateau
Posted: Thu May 13, 2021 12:44 am
L22 - Aristarchus Plateau - Mysterious elevated region covered with pyroclastics 26,0N 51,0 W
I think that at that time of the championship I already photographed almost all the objects on the lunar list of my good friend Chuck Wood (https://en.wikipedia.org/wiki/Lunar_100). To be honest, I never bothered to stick to the list, I just take pictures of places that I find interesting, but it would be an extremely interesting project to meet all 100 high resolution goals with amateur equipment.
Anyone who looks at this photo and sees the beauty of Plateau Aristarchus next to the two craters that accompany it, does not even notice the Herodotus Omega dome, in fact most of us put the observation of the deep sky on hold when the lunar glow intrudes on the dark skies. But why, instead of limiting your telescope, don't take the opportunity to observe the Moon itself? The crescent moon phase is a good time to become familiar with one of the most evocative features of our satellite: its domes.
Many of the Moon's characteristic landscapes were created by impact. Craters, rays, mountain ranges, seas and basins abound. The lunar domes are different. They formed as a result of the Moon's own internal volcanism. Similar to shield volcanoes in Iceland and Hawaii (including Mauna Kea on the Big Island) in addition to Olympus Mons on Mars, they form when highly fluid lavas spring through a central caldera in the surface. They are almost all of low explosiveness, unlike their cousins, the most violent terrestrial stratovolcanoes that occupy the headlines.
Like a leaf stacked after another, after the lava flows under the crust, a dome slowly builds up over time, forming a wide and gently tilted mound like a warrior shield with a high center and a lower edge. Shield volcanoes can be small, like Icelandic and lunar varieties, or wide and huge, like Olympus Mons. A typical lunar dome measures between 5 and 7.5 miles (8-12 km) in diameter with a peak or caldera ~ 900 feet (~ 300 meters) in height. The slopes are very smooth with just a few degrees.
More than 300 lunar domes are known, many visible on amateur telescopes with 3-inch openings upwards. There are two key requirements for good dome observation - good atmospheric stability (seeing) and observing the dome near the terminator shortly after the lunar sunrise or before sunset as was done in this photo with Herodotus Omega.
Most domes are subtle, low-contrast features that become sizzling with poor seeing. Low light, produces long shadows on the peaks and edges of the craters, and makes their gently tilted shapes have the best contrast. You will be more excited when you can see the boiler. When you see the dome hole, you really see a dome for what it is: a volcano previously active on the days when the moon still had intense geological activity.
About 60 km southwest of the Herodotus Crater at the Oceanus Procellarum it is easy to find Herodotus Omega. A dome 6 miles wide (10 km) covered by a boiler on the summit, visible in good view even with a modest telescope using high power.
The next time you go to watch the Moon near the end, don't forget to pay attention to these rounded shapes that easily stand out in relation to the surrounding terrain, be sure to remember that the Moon once had its volcanoes active and even today it is far of being the dead world that many believe.
Source: Lunar 100 - Chuck Woods
Sky and Telescope - A short guide to lunar domes - Bob King
Wikipedia - Lunar Dome
Adaptation and text: Avani Soares