“No Sun Spots Visible”

April 26, 2022 Michael L Umbricht Leave a comment

―John Edwards, 1913.

In February 1907 John Edwards, assistant to astronomy professor Winslow Upton, recorded a drawing of spots that he observed on the Sun. Due to the brightness of the Sun it is not safe to look at it through a telescope. Instead he used a method called eyepiece projection which forms an image on a sheet of circular graph paper. The outline of the spots can then be accurately traced with a pencil. The sketch shows a complex arrangement of sunspots during a month when the Sun was very active. This was shortly after the peak of the Sun’s 11 year cycle of increasing and then decreasing activity. Sunspots appear in active regions where there are strong and complex magnetic fields.

Sunspot drawing — Sunspot observations, February 11, 1907 at 9:55 am.

By 1913 the Sun’s cycle had reached the minimum of the cycle and no spots were visible during some months that year. It is important to note the lack of sunspot activity so that someone examining the preserved records a century later knows that the astronomer looked and didn’t find any. Otherwise it might be thought that the data was merely missing. Notice that on Jul 18, 1913 there is a note that it was cloudy that day.

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astronomy, history, meteorology

Eclipse meteorology

April 26, 2022 Michael L Umbricht Leave a comment

“Plan of Observations. -The meteorological observations proposed were especially directed towards the subjects of barometric pressure, air temperature, humidity, solar radiation, and wind velocity. The instruments located on the top of the tower were in charge of Mr. Rotch, and those at its base Mr. Upton.”

―Winslow Upton and A. Lawrence Rotch, Meteorological and other observations made at Willows, California, in connection with the total solar eclipse of January 1, 1889. Annals of the Astronomical Observatory of Harvard College, Vol. XXIX, 1893.

Diagram of the solar eclipse — Drawing of the total solar eclipse of January 1, 1889

The scientific instruments used during a solar eclipse include telescopes with a protective filter to reduce the brightness of the Sun to protect an astronomer’s eyesight. The earliest known image of the Sun taken by a camera was recorded in 1845. But it was still common for scientists to draw sketches with pencil and paper as it has been done for centuries. The above image is based on a number of photos taken with different exposure times. The short exposures record bright features but leave out many of the fainter ones. The longer exposures cause the bright features to be overexposed but reveals subtle details. The sketch above is a composite of these different photographs.

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astronomy

A Minimal Penumbral Lunar Eclipse and Two “Meteorocre” Shooting Star Displays

June 25, 2020 [email protected] Leave a comment

“What’s in a name? That which we call a July Full Moon
By many other names would shine as bright.”

My apologies to William Shakespeare, but I simply couldn’t resist mangling the above famous quote from Romeo and Juliet.

Full Moons have a myriad of names. Here in the United States the colonists adopted many of them from Native Americans, predominantly the eastern Algonquin nation. While these descriptive names have become the primary ones by which we identify each Full Moon, many other names have been ascribed to them.

For example, the July Full Moon is usually called the Full Buck Moon. This name was one brought over by the colonists from Europe. Male deer in both Europe and North and South America shed their antlers yearly, and by July a new set has emerged. Another old-world name for this Full Moon is Hay Moon, signaling when the hay field had been reaped. And finally Thunder Moon has been used for obvious reasons during northern hemisphere summer months.

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astronomy

Supernova deferred (for now), Easter, and a meteor shower

April 9, 2020 [email protected] Leave a comment

As 2019 came to a close, the news media sensationalized a story about Orion’s bright star Betelgeuse. The headlines were certainly designed to get one’s attention. Betelgeuse was about to go supernova. However, the star’s behavior was really old news that was recently enhanced by new observational data. You see, Betelgeuse is a red super giant star (20 times more massive than our Sun and approximately 1000 times larger) that is indeed nearing the end of its life cycle. And with a star this massive, the result will someday be a supernova event.

Betelgeuse is a known variable star, which pulsates back and forth about one full magnitude (brightness scale) in a 425-day period. What happened more recently is that the star dimmed a little more than usual, by about .2 of a magnitude. An imaging technique using radio waves revealed Betelgeuse appeared to be lopsided, but this discovery turned out to be a huge dust cloud blocking some of the star’s light from reaching us. In fact, Betelgeuse has shed off great shells of its outer surface several times in the past, typical activity for these stars as they “burn” through their supply of nuclear fuel. Speculation arose that Betelgeuse’s grand finale was soon at hand.

However, every article I read succinctly stated the event could happen soon, or 100,000 years from now. While it is inevitable that Betelgeuse will go supernova in the future, we needn’t worry. Fortunately, at its distance of about 700 light years from the Earth, we will not suffer from any hard radiation effects. The supernova will be at least as bright as a Full Moon and will be visible in broad daylight. About a day before we see the visible light from the supernova event our Earth will be bombarded by a harmless hail of neutrinos and gamma rays. That onslaught will be our advance warning system that Betelgeuse the star has met its demise.

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astronomy

Pluto at Ninety: Discovered, Demoted, Visited

March 6, 2020 [email protected] Leave a comment

A little more than ninety years ago, in a barred spiral galaxy named the Milky Way, a stellar system named Sol had a retinue of eight known planets revolving around it. The last one to be discovered was Neptune in September 1846. However, as time passed small perturbations in Neptune’s orbit were noted, which suggested another “trans-Neptunian object” existed whose presence altered his path around our Sun. It wasn’t until 1905 that a wealthy Boston astronomer, Percival Lowell, started a search for “Planet X” using his Flagstaff, Arizona, observatory. Lowell, with his mathematics background, and with the help of colleagues, tried to derive a possible orbit for a potential unknown planet. They even took photographic plates in 1906 of an area of sky where they thought planet “X” might be located, but with no results.

Unfortunately, Percival Lowell died at age 61 on November 12, 1916 and the search for the elusive “Planet X” ended. However, in 1929, the search for Pluto was resumed at the Lowell Observatory using calculations that Lowell had computed earlier. A 23 year-old Clyde W. Tombaugh was hired to meticulously image specific areas of the sky using photographic glass plates. The same star field would be exposed several days apart. Once the plates were developed, they were placed in a viewing machine called a blink comparator that held two plates. The operator could switch back and forth from one plate to the other. This process was called “blinking.”

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