SKY GUIDE: This map represents the night sky as it appears over Maine during September. The stars are shown as they appear at 9:30 p.m. early in the month, at 9:30 p.m. at midmonth, and at 8:30 p.m. at month’s end. Saturn is shown at its midmonth position. To use the map, hold it vertically and turn it so that the direction you are facing is at the bottom. Sky Chart prepared by Seth Lockman

The month of September always marks the beginning of autumn for us in the northern hemisphere. This year that will happen at exactly 8:44 a.m. on Sept. 22. This autumnal equinox, along with the vernal equinox in spring, are the only two days each year that the sun rises due east and sets due west for everyone on Earth except for the poles. The days are also 12 hours long within a few days of the equinoxes for everyone on Earth except for the poles.

This was a hotter-than-usual summer along with more days of wildfire smoke from out-of-control wildfires all the way from the west coast but mostly from Canada. This enhances the red sunsets and the moon will maintain a nice orange color for much longer than usual, but all of this smoke and haze adds a lot of tiny particulate matter to our atmosphere which is not healthy for many people. It also makes the night sky viewing kind of fuzzy, even if it is clear.

The nights will be getting noticeably longer now as we head into fall, so get outside when you can to enjoy the crisper weather and everything that the night sky has to offer. There are many good highlights this month including Saturn at its best for the year, a good apparition of Mercury in the morning sky, and Comet Tsuchinshan-ATLAS brightening as expected heading for a potentially great showing next month if it survives its dangerous dive around the sun at the end of this month. The soft glow of the zodiacal light will start to become visible in the morning sky this month a couple of hours before dawn. It will also be visible next month and on into part of November. A dual occultation of Saturn and Neptune by a full moon on Sept. 17 will be interesting to watch in a telescope. Then we will even have a short partial lunar eclipse of the full Harvest moon this month. It has already been six months, a full eclipse season, since the last great total solar eclipse that millions of people saw right here over Maine on April 8.

I attended the annual Stellafane convention in early August this summer. Celebrating 100 years, this is the oldest star party in the world. In spite of rain and cloudy weather for both nights, nearly 1,000 avid amateur astronomers attended this great event this summer. It basically began when Russell Porter built an observatory in Springfield, Vermont in 1923. He was also an artist, engineer, architect, and Arctic explorer. Russell would go on to design and build the observatory dome for the 200-inch telescope atop Palomar Mountain, the largest telescope in the world for many years, designed by George Ellery Hale.

This great convention is like an annual pilgrimage for many amateur astronomers, and it should be required attendance at least once in a lifetime for true amateurs that want to keep learning and sharing. It is always inspiring to attend the workshops and talks there regardless of the weather, although clear skies would be a nice bonus. You always meet many great new people there and exchange ideas. Many famous and not-so-famous astronomers had their start at Stellafane and they went on to do great things and make a name for themselves.

Some of the talks included several more accounts of unique individual experiences along with great pictures of the recent April 8 total solar eclipse, the prospects for Comet Tsuchinshan-ATLAS to become a great comet soon, new data on star clusters and asterisms from the GAIA space telescope which has already mapped over one billion stars in our own galaxy, and a good talk on binoculars which is always popular and an easy way to get into astronomy and appreciating the night sky in more detail.

Saturn will reach opposition on Sept. 8. That means it will rise at sunset, reach its highest point in the sky at midnight, and not set until sunrise, similar to the full moon which reaches its opposition each month. Saturn reaches opposition every 378 days.

If you look at Saturn through a telescope you will notice that its rings are nearly edge-on now, tilted at only 4 degrees open. The maximum angle is 27 degrees. Since it takes Saturn just under 30 years to orbit the sun, its rings will appear edge-on twice during this time. This last happened in 2009 and 1996 before that. They will become completely invisible again in March of 2025.

The benefit of these thinner rings is that Saturn will appear less bright which means that you can see more of its moons through a telescope. I have seen as many as seven of its 146 moons, but now you will be able to see nine of them if your telescope can reach 14.5 magnitude, which is also about the brightness of Pluto. You can usually see about four to five moons of Saturn if it is a good night and the telescope you are looking through can reach at least 10.4 magnitude. In their order of brightness these moons are: Titan, Rhea, Tethys, Dione, Iapetus, Enceladus, Mimas, Hyperion, and lastly Janus at 14.5 magnitude, or fully 250 times fainter than Titan. Because it is covered in ice, Enceladus is the most reflective body in the entire solar system. It also has the best prospects for life other than Jupiter’s moon Europa, since they both have huge liquid oceans located 50 miles or more below their solid icy surfaces.

Mercury will make its best morning appearance for the year early this month in Leo. Our first planet will be only half a degree from Regulus 30 minutes before sunrise on the morning of Sept. 9. And a slender waning crescent moon will pass just to the left of Mercury on the first day of this month.

Venus is still slowly getting higher in our evening sky but it will not really become easily visible until October. Watch a waxing crescent moon pass right by Venus and Spica in Virgo on Sept. 5.

Jupiter rises around 3 a.m. in Taurus followed by Mars about an hour later in Gemini. The last quarter moon will pass near Jupiter and then Mars on Sept. 24-25 and near Castor and Pollux on Sept. 26.

Comet Tsuchinshan-ATLAS will be visible low in the eastern morning sky near Leo waning crescent moon during the last few days this month. Hopefully it will survive its dangerous plunge around the sun and become a brilliant evening comet next month.

There will be a short partial lunar eclipse during the full moon this month on the evening of Sept. 17 into Sept. 18. The moon will just barely graze into the earth’s umbral shadow for an hour with the deepest part happening at 10:44 p.m. It should be easily detectable if it is clear. There will be an annular solar eclipse visible over South America two weeks after this partial lunar eclipse on Oct. 2.

Then everyone is waiting for T Corona Borealis, the Blaze Star to explode again. I was watching it carefully recently while looked for Perseid meteors and nothing happened.

SEPTEMBER HIGHLIGHTS

Sept. 2: New moon is at 9:57 p.m.

Sept. 3: Viking 2 landed on Mars in 1976.

Sept. 8: Saturn reaches opposition and is visible all night long.

Sept. 11: First quarter moon is at 2:07 a.m.

Sept. 17: Full moon is at 10:34 p.m. There will also be a partial lunar eclipse tonight peaking at 10:44 p.m.

Sept. 22: Autumn begins in the Northern Hemisphere at 8:44 a.m.

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