What & # 39; s Up in September: the lightest planets shine in the air of autumn



Autumn always starts in September for us in the northern hemisphere.

This will happen at 21:54 this year. on Saturday the 22nd. This will mean the end of a long, hot summer, because the nights will cool down and become more transparent, even if they get shorter, and go back to winter.

The autumn and the spring equinoxes are both interesting days on earth because they mark the only two days a year when the sun rises straight to the east and rises straight ahead to the west for everyone on earth, with the exception of the poles. Within a few days the equinoxes are also the only two days per year that are exactly 12 hours long for everyone on earth except the poles. The reason is our slightly elliptical orbit around the sun and our 23.5 degree tilt on our axis.

The days are always 12 hours long at the equator and they experience no seasons, but the rest of the world does. The seasonal changes are especially fun in New England, because there is a slow and continuous transformation going on, both in our view of the sky above us and on the ground below, because we always orbit around the earth and only a hemisphere or the tilt the other a bit. more to this life-giving natural force that affects everything.

The highlights of this month are that all four brightest planets are still visible in our evening sky at the same time. There will also be some nice conjunctions of the moon with all those planets, but not good meteor showers until next month.

Venus is the brightest of the four and the first one in the west, about an hour after sunset. Note that the beginning of this month will be only one degree lower left of Spica in Virgo. Our sister planet is still brighter in our air while he continues to follow us in his job. We have already passed our other neighbor, Mars, but both are still much closer to the earth than usual. Venus is becoming brighter, even if it is less illuminated by the sun. It will be only 18 percent lit up by the end of the month, similar to a decreasing crescent moon.

Then continue east along the ecliptic and you will encounter Jupiter in Libra, just one constellation east of Venus. Note that Venus catches up with the Jupiter during the month, and that gap narrows close to just 14 degrees at the end of it. Jupiter has been back in the air since mid-July. So the king of the planets keeps fading a little more as we move forward. The month starts with setting around 10 o'clock in the morning. and the setting of the month ends 2 hours earlier.

Jupiter is still very close to a double star in Libra with the long Arabic name Zubenelgenubi, but it slowly drifts further away from this star whose name means "the southern claw". Libra used to be part of Scorpius, the next constellation for the East.

Then go about 30 degrees east along the ecliptic, the largest gap between one of the four planets that is now visible, and you will encounter Saturn in Sagittarius. The rings are still tilted open in the vicinity of their maximum of 27 degrees, although it dims slowly, because it is now a few months past. You will easily see his biggest moon, Titan, through a telescope and you could even see four or five moons on a good night.

The last in this great planetary arrangement that has been with us all summer is Mars. The red planet was at its best in 15 years, but it will be much brighter and bigger than normal for a few months. It even got brighter last month than Jupiter, but Mars will blur a little bit more this month and become less clear than Jupiter again on the 7th while the Earth now moves further ahead of the red planet in our faster orbit around the sun.

I was able to see some detail on the surface of Mars last month through different telescopes. I could see some dark markings and a hint of both the northern and southern polar caps. This time I did not see any of the Mars atmosphere because of a number of planet-wide dust storms covering a large part of the surface.

There will be almost four lunar Universe connections with the planets this month, because the moon will mark each of those planets as they move on their designated paths along the ecliptic. We begin with the slender crescent that points at Venus on the 12th, then it will be only 4 degrees north of Jupiter on the 13th, then just 2 degrees north of Saturn on the 17th and eventually this cycle will be 5 degrees north of Mars on the 20th. The moon moves about 12 degrees east each day along the ecliptic.

I attended the annual Stellafane convention last month. This is the oldest and one of the biggest stars in the world. Almost 1,000 enthusiastic amateur astronomers attended this summer. It was held during the peak of the Perseid meteor shower and near new moon. This is an annual pilgrimage for a diverse group of people who share a common interest. Everyone learns new things there and shares new experiences as they gaze through hundreds of amazing telescopes to the sky above, always getting new visions of our familiar air and its innumerable content, expanding our cosmic perspective from where we really are, all the time .

There are hands-on workshops as well as many great presentations for everyone. I attended a bit about astrophotography, light pollution, variable stars and binoculars. The main speaker was Samuel Hale, the grandson of George Ellery Hale, the most famous telescope maker in the world, who designed and built the four largest telescopes in the world from 1898 to 1938.

Todd Mason also gave a great presentation. He made the documentary & Journey to Palomar & # 39; and now makes computer graphics of the largest new telescopes in the world to show people what they look like and how they will really work when they are finished. These include the Large Synoptic Survey Telescope which will find thousands of potentially dangerous asteroids, the Giant Magellan Telescope with its seven-mirror segments equal to 25 meters, and the Extremely Large Telescope with a 39-meter mirror, almost 4 times larger than the largest telescope in the world today. They should see the first light within seven years or so and they will probably completely overthrow our current limited understanding of our universe.

Sept. 3: On this day in 1976 Viking 2 landed on Mars, only a few weeks after Viking 1.

9 September: New moon is at 14:03 hours.

Sept 12: The moon will be near Venus tonight.

Sept 13: The moon will be near Jupiter tonight.

Sept 16th: the first quarter is the moon at 7:16 pm.

September 17: The moon is near Saturn tonight.

Sept. The waxing, gibbous moon will be near Mars tonight.

22 September: Autumn starts today at 21:54. as the sun goes down over the celestial equator.

23 Sept .: J. Galle discovered Neptune on this day in 1846. Two other astronomers calculated exactly where this planet should be based on its influences on other planets. Neptune is now at its best in Aquarius, but you need a telescope to see it. It had only made one orbit around 2011, 165 years after it was discovered.

Sept. 24 Full moon is at 10:54 am. This is the famous Harvest Moon because it is closest to the equinox.

Bernie Reim from Wells is co-director of the Astronomical Society of Northern New England.

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