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My 9/27/2015 lunar eclipse experience

September 28, 2015 Comments off

This is an elaboration of an email sent to a fellow amateur astronomer who was completely clouded out and asked how we did.

The Grand Traverse Astronomical Society decided to split our forces for the eclipse.  Some of us would be stationed at the Rogers Observatory, south of Traverse City; while the other would participate in an eclipse watch at the Sleeping Bear Dunes National Lakeshore about 30 miles to the northwest of Traverse City. For most of the week before, the weather forecast was for clear weather.  Well, it was not to be.  All day we were under low clouds streaming up from the southwest.
I headed the contingent that would join a park ranger at the spot in the park called the Dune Climb.  There was a mix-up in the location of the watch.  I had it at a location 20 miles to the south.  So I went to that location and posted a sign about the change in venue and headed north to the Dune Climb.  On my way, I ran into some misty rain.  Not exactly encouraging.  On the satellite images I was tracking all day Sunday, the western edge of this big cloud system was over Lake Michigan.  I was hoping a weather system approaching from the northwest would push this cloud system out of the way.  It didn’t quite.
At the Dune Climb, we had reports from one of the visitors that they had seen the Moon from the town of Empire, about 5 miles south of there.  That was before the eclipse started.  At about 9:15 the park ranger Peggy welcomed everyone and soon turned the mic over to me.  Two other members of the GTAS had arrived before me:  Don Flegel and Emmett Holmes.  Don would use the park’s 4-inch refractor.  Emmett brought his wonderful wooden 13 inch telescope on a Dobsonian mount on a Poncet platform.  Both telescopes would be deployed if the skies cleared.  I brought my telescope, but it turned out that I was spending too much time yakking to actually set it up.  With no Moon visible, I ended up talking all about lunar eclipses, and what to expect if the Moon ever popped out of the clouds.  I talked about lunar eclipses, then turned to the solar eclipses I’ve seen and other topics in response to questions, for about an hour and a half.  At about 10:30 we noticed we could see stars to the low southwest over the dunes.  It took 15 minutes, but the hole in the clouds expanded and finally uncovered the Moon at about the mid-eclipse point.

From mid-eclipse, about 10:45, to the end of totality it was almost perfectly clear,  We had light clouds after that to the end of the partial phase.  Then it clouded up again.  My impressions of the eclipse brightness at totality was that it was a bit darker than usual, but I may be wrong.  However, I have had wretched luck in being able to view lunar eclipses.  We were virtually wiped out by clouds with the two lunar eclipses last year, and we’ve had the same luck for the many eclipses occurring before.  I may be out of practice.

The folks stationed at the Rogers observatory were indeed clouded out.  To paraphrase the crusader in Indiana Jones and the Last Crusade:  “We chose wisely.”  Or it was plain dumb luck.
Satellite cloud image

From the animation of the satellite images from Sunday night. The red circle points to the hole, really a notch in the clouds that allowed us to see the last part of the lunar eclipse.  Our low clouds were warm in the infrared, so show as a very light gray. Credit NOAA/Environment Canada.

Categories: Adventures, Lunar Eclipse Tags: ,

09/28/2015 – Ephemeris – The Harvest Moon effect

September 28, 2015 Comments off

Ephemeris for Monday, September 28th.  The Sun will rise at 7:36.  It’ll be up for 11 hours and 52 minutes, setting at 7:29.   The Moon, 1 day past full, will rise at 8:00 this evening.

Yesterday’s full moon was the famous Harvest Moon, the nearest full moon to the autumnal equinox.  This is a time of the full and waning gibbous moons in the next few days rising in twilight.  In the old days before electric lights it helped farmers by effectively lengthening the hours of light to gather in the crops.  The Moon on average rises 50 minutes later each night.  The interval between tonight’s moon rise and tomorrow’s will be 38 minutes.  The interval between Tuesday and Wednesday will be 42 minutes.  This year’s harvest moon effect is spoiled a bit because the Moon was at perigee Sunday, the so-called supermoon, so it’s moving faster in its orbit than average.  Like the Sun, the Moon always appears orange or red near the horizon.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Path of the Harvest Moon

The positions of the Moon from September 28 to October 1, 2015. Note the path of the Moon. At Harvest Moon in northern Michigan time it makes less than a 45 degree angle with the horizon. For other latitudes it’s less than (90 – latitude). shorthand term for 90 – latitude is co-latitude. Created using Cartes du Ciel.

The closer to horizontal the Moon’s path is the shorter the difference in night-to-night rise times.

Categories: Ephemeris Program, The Moon, Uncategorized Tags: ,