Kansas Snapshots by Gloria Freeland - September 28, 2018

Glorious autumn

When I awoke last Saturday, it was 49 degrees, a welcome contrast to the 90+ temperatures we’d had just a few days before.

“How appropriate,” I thought. It was, after all, the first day of autumn.

I’ve always enjoyed the fall, and Saturday’s opening day of the season was a glorious beginning with sun, blue sky and just a slight breeze.

I enjoyed a cup of coffee with daughter Mariya and her wife Miriam on their back patio. Although their home is in the middle of town, their fenced back yard always seems like a little oasis. While we were relaxing, a chattering squirrel in a nearby oak tree scolded their cat Phil.

Later, we went to the weekly farmers’ market located in a parking lot at the downtown mall. At one booth, the last of summer’s bounty - peppers, tomatoes, green beans and potatoes - joined typical fall items like squash, cabbage, apples and peaches. Another stand was labeled “Summer’s End Farm” and it had large pumpkins on display. A message on a chalkboard at another booth proclaimed, “Hooray for sweaters!!” There were also hand-made tea towels with Halloween and Thanksgiving motifs.

The girls bought honey and I purchased peaches and two kinds of day lilies - one for them and one for husband Art and me. Everyone - customers and booth owners alike - commented on what a beautiful day it was.

We humans like to label what we see as special days, and the first day of a new season is one of those. The start of fall and the end of summer is also called the autumnal equinox. Doing a little Googling once I was home, I discovered “equinox” comes from the Latin words - “aequus” and “nox” - which mean “equal” and “night.” So the equinox must be the day when all areas on the surface of the globe receive an equal amount of sunlight and darkness - 12 hours each.

However, when I checked the sunrise and sunset for Manhattan, Kansas for Sept. 22, I found the former was 7:14 a.m. and the latter was 7:23 p.m. Hmm, the day was longer than the night by nine minutes. Trying other days, Sept. 26 seemed to be closest with sunrise at 7:17 and sunset at 7:18. The following day had a longer night than day. So why wasn’t Sept. 26 the autumnal equinox?

More Googling led me to an answer that was not so simple!

Part of the answer lies in the fact that we use the top edge of the sun when it first peeks over the horizon as sunrise, but sunset is when we lose sight of the last sliver. If we used the same point on the sun to determine both, it would shave about two minutes off the nine-minute difference.

Another part is that the air acts a bit like a prism and bends the light from the sun. We actually see the leading edge before it has truly risen above the horizon and, in the evening, can see the trailing edge when it is already below the horizon. This accounts for the additional lengthening of the equinox days.

It is interesting that this effect varies with air temperature and pressure as both change the air density. So if a day is unusually cool and the air pressure is high, the actual day may be even longer than what the weather people say as they use average temperatures and pressure to calculate sunrise and sunset.

Back in 2002, I wrote a column about watching the sunrise with daughter Katie and niece Larisa on “Day Star Day.” That was the name astronomer Jack Horkheimer gave to the first day of summer to emphasize that the sun is just another star. Since the additional time added by the effects mentioned above should be in effect on Day Star Day, it should still be the longest day of the year. And when I checked, it was. And the start of winter, Dec. 21, was indeed the shortest.

There were two additional things that were at first confusing. If noon is the middle of the day and the sun is at its farthest point from the horizon, it would seem that on the day of the equinox, sunrise would be six hours earlier and sunset six hours later. So why were the fall equinox times closer to 7 a.m. and 7 p.m?

Most of the answer is Daylight Saving Time. Take away the spring “leap ahead,” and sunrise would have been 6:14 a.m. and sunset 6:23 p.m.

The remaining part has to do with the fact that within a time zone, we say the time is the same, but events such as sunrise and sunset will occur later the farther to the west one is located from the start of the zone. The Central time zone begins at approximately where St. Louis, Missouri is located, and Manhattan is about 350 miles to the west of that.

After shutting down my computer, I had to smile. The weather was beautiful and a relief from the stifling heat we’d had earlier in the week. I had spent time with two of my favorite people and visited a farmers’ market. As a bonus, I learned that the days and nights are not quite equal on fall and spring equinox days and why that is so.

But when I mentioned these things to Art, he brought up another reason we both like this time of year. We met in August 1987, but he soon left for his annual month-long trout fishing trip in Wisconsin. He returned near the time of the equinox that year and that was when we really began to get to know one another.

“You must have a photo of those times.” he commented.

Indeed I do. But the picture we liked best was a bit later in the fall. It made both of us smile. Ah, glorious autumn!