They surmised that impacting objects, coming in from all angles would give rise to elliptical craters with their major axes aligned to the direction of travel. Many years ago some authorities thought that, as the vast majority of craters are round, they must have been the result of volcanic activity. This secondary crater chain is radially orientated to Mare Nectaris so it may have been gauged out by 10 or more gigantic ejecta fragments when the Nectaris basin was formed some 4,000 million years ago. To the lower right of the visible disk is Vallis Rheita which has a length of 445 km and a maximum width of about 30 km. The two mountain chains, Caucasus and Hamus, seen at this lunar phase, are found on the western side of Mare Serenitatis. Mountain chains tend to be the found at the edges of the basins that were the result of major impacts and which were later filled with lava to form the maria. As shown in the comparison image above, these are visible at times with Mare Humboldtianum, Mare Marginis, Mare Smythie and Mare Australe seen in the day 5 image above. There are four further maria that can only be well seen when the Moon’s libration allows one to ‘see’ a little around the eastern limb of the Moon. This is not a particularly good image compared with those that I can now take but, pleasingly, shows the effect of libration very well as seen in the comparison with the Day 6 image.īesides the six that are easily visible, there are two small maria, Spumans and Undarum close to Mare Fecunditatis. I found an image of the 5 day old Moon in my files that had been taken on the 7 th January 2003 with a compact camera and 80 mm refractor using eyepiece projection. Virtual Moon Atlas ( ) can beautifully show the Moon’s libration by simply holding down the left mouse click over the ‘>’ tab in the ephemeris command window. In fact, 59% of the Moon’s surface can be seen over time. ![]() Below is an image taken by the author of the six day old Moon and the remainder of this article describes some of the more interesting features seen at this phase of the Moon.ĭue largely to the fact that the Moon’s orbit is elliptical but also that when we observe it at dawn and dusk our view point relative to the Moon is shifted from when we observe it on the meridian (the effect of parallax), at times we can see further round the eastern and western limbs than at other times. Over the next few days, the illuminated phase gets greater and, as the Moon moves further in angle from the Sun, it will be seen for longer after sunset and be higher in the sky. This is a composite of two exposures one to correctly expose for the bright limb and a second, with a considerably longer exposure, to expose for fainter parts of the surface. At this time (and also when seen just before dawn in the east) it may be possible to observe ‘Earthshine’ illuminating the ‘dark’ part of the lunar disk as shown below. The first chance of observing the Moon after ‘New’ is when a very thin crescent Moon becomes visible low in the west after sunset.
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