A peek at the Solar Dynamics Observatory website today revealed a spectacular series of magnetic loops belonging to an active sunspot group just beyond the eastern limb of the sun. It will rotate over into view in the next few days, but we’re already getting a preview of it through glowing loops of gas bound up in the group’s magnetic field – similar to a sprinkling of iron filings that outline the magnetic field around a common magnet. The loops lie high in the sun’s atmosphere allowing us to glean the group’s presence beyond the limb.
The same group kicked out a spectacular CME or coronal mass ejection of material into space yesterday evening. Though not directed at the Earth, it hints at good things to come after a week of the doldrums. Aurora watchers look forward to any uptick in solar activity.
Tonight the moon reaches first quarter phase, so called because it’s traveledÂ a quarter the way around its orbit since new moon. First quarter is one of the best times for moon viewing because it’s conveniently placed high in the southern sky at sunset and doesn’t set till midnight. With the naked eye, you can see four or five large dark patches or lunar seas labeled in the photo above. The easiest ones, Serenity and Tranquillity, form the two eyes of the ‘man in the moon’ visible at full moon.
7x and higher power binoculars will show a crinkly texture along the moon’s terminator created by the thousands of craters lit by low-angled sunlight there. If you’ve got steady hands, you may even be able to discern the outlines of the larger ones. Up near the top or north end of the moon, look for two rumpled, bumpy arcs. The larger one is the Apennine Mountain range which spans 370 miles with peaks rising to 3 miles high. To its north are the Caucasus Mountains.
Both are named after their earthly counterparts, but neither formed through plate tectonics like Earth’s mountain ranges. These are rings of lunar rock created during asteroid impacts long ago.
Telescopic observers will delight in all the craters and shadowy textural details that festoon the terminator at first quarter phase. Trust me, any scope will give you an eyeful tonight. Excellent crater and mountain viewing continues for the next several nights as the moon waxes toward gibbous phase.