The Weather Bureau in Providence

“In Philadelphia I dragged out a colorless and an unhappy existence till September, 1904, when to my delight I was ordered back to New England, and this time nearer the centre of civilization. (Of course by that I mean Boston, which is the “hub of the universe” the “Athens of America”, the “Centre of Culture”, and last but not least, the home of the humble baked bean and the sacred codfish). I was sent to Providence, R. I., and have remained here ever since and hope to continue my residence here. By a happy combination of circumstances I have lived in the classic halls of Brown University ever since my arrival in Providence. The location and environment are eminently satisfactory.”

– George Francis Field, “Harvard College Class of 1901.” June 1911

University Hall Weather Bureau
An instrument shelter on the roof of University Hall.

In addition to the weather station at Ladd Observatory there was another on the Brown campus. Located on the roof of University Hall it was operated by the U.S. Weather Bureau. The pole behind the chimney at left was likely used to support the anemometer, an instrument to measure wind speed. Continue reading The Weather Bureau in Providence

“The Magic Voice of Science”

“This is truly scientific magic. Just think of it! You want to know the true time to the fraction of a second, and all you have to do in order to get it is to open your electric ear to these sounds, which seem to drop out of the sky, as if Old Time himself were speaking to you!”

– Garrett P. Serviss, Wireless Time Signals from the Eiffel Tower. Washington Post, September 7, 1913.

During 1913 the Washington Naval Observatory and the Observatoire de Paris attempted to exchange wireless time signals. The experiment was used to calculate the difference in longitude between the two locations more accurately than was possible with other techniques. They were also trying to measure the velocity of radio waves through space. The goal was to improve communication with ships at sea which used the time signals to calibrate the chronometers used for celestial navigation. For most of the year atmospheric conditions prevented the reception of the signals sent across the ocean. The conditions improved in November and the two observatories were then in regular contact by radio. Prof. Winslow Upton of Ladd Observatory was listening in on the transmissions.

Upton notebook
The notebook of Winslow Upton describes reception of the “Special Wireless Signals from Washington” in November, 1913.

Continue reading “The Magic Voice of Science”

“The pendulum of eternity”

“The vast cycles of change going on in the heavens seem, as it has been sublimely said, like the recurring beats of the pendulum of eternity.”

– William Augustus Norton, First Book of Natural Philosophy and Astronomy, 1860.

Providence Union Station, 1847-1896.
Providence Union Station, 1847-1896. The Foucault pendulum was suspended within one of the towers at left.

When news of Léon Foucault’s demonstration of the Earth’s rotation reached the United States in 1851 there was great interest in repeating the experiment in Providence. Two members of the Brown faculty arranged for a public demonstration in the Providence railroad depot. Alexis Caswell was a professor of natural philosophy, mathematics, and astronomy. William A. Norton was professor of civil engineering and natural philosophy. The pendulum bob weighed a little less than 40 pounds and was suspended from the end of a wire 97 feet long. The report on this experiment was published in the Proceedings of the AAAS along with an account of the Harvard demonstration in the stairwell of Bunker-Hill Monument. Continue reading “The pendulum of eternity”

The highest point in Providence

The site chosen for Ladd Observatory was at the top of the highest hill in the city of Providence. The hill lost that distinction in 1919.

The borders of Providence have changed a number of times. The settlement of Silver Lake was originally part of Providence, but the residents decided that this agricultural community had more in common with rural Johnston and choose to secede in 1759.

USGS 1894
The border of Johnston and Providence ran through Olneyville Square. Rocky Hill is in Cranston. USGS topographic map, 1894

Continue reading The highest point in Providence

Timing the transit of Mercury, 1907

“About five seconds before third contact a black ligament connected the planet’s disk with the trembling edge of the Sun.”

– Winslow Upton, “Transit of Mercury at Ladd Observatory.” Popular Astronomy, 1907.

1907 transit of Mercury
Chronograph recording of the Transit of Mercury on November 14, 1907.

Prof. Winslow Upton tapped a telegraph key as he watched the planet Mercury transit the Sun. The signal was sent to a chart recorder where an electromagnet moved a pen on a slowing turning drum of paper to record the observation. The instrument is called a chronograph. This one was made by the Warner and Swasey Company of Cleveland in 1890. Primarily it was used for calibrating the astronomical regulators (precision pendulum clocks) to set the time accurately. It was also used for timing events such as lunar occultations of stars. Continue reading Timing the transit of Mercury, 1907

Observing the “rain-bands”

The Leonid meteor shower was approaching and as the astronomers prepared cameras to capture the event they must have wondered: will the skies be clear tonight?

Leonids 1898
Astronomers preparing cameras to capture the Leonid meteor shower, Nov. 14, 1898.

Prof. Winslow Upton taught astronomy at Brown from 1883 until his death in 1914. He also had a keen interest in meteorology. He had been a professor of meteorology at the Weather Bureau of the U.S. Signal Survice from 1881 until 1883. In 1884 he was one of the organizers of the New England Meteorological Society and operated a weather station at Ladd Observatory starting in 1890. We can gain some insight into how he might have forecast the cloudiness of the sky by noting a curious instrument to the left of the cameras in the photo above. Continue reading Observing the “rain-bands”

The dark side of the Moon

Automated instruments on the roof of Ladd Observatory monitored the sky during the total lunar eclipse of Sept. 27-28, 2015. First there is a wide field sky camera. It has a fish-eye lens which can capture an image of most of the sky above Providence. The second is a sky brightness meter which is used to monitor light pollution.

Eclipse sky
An image from the sky camera during the total phase of the eclipse. (Click on the image to see a time lapse video.)

The full Moon is usually so bright that it overwhelms the sensitive camera causing the images to be overexposed. During the eclipse the Moon was dark enough that the only artifact in the image above is a thin vertical line where one column of the digital camera was saturated by the moonlight. The camera is more sensitive than the human eye allowing the Milky Way to be seen during the total phase of the eclipse. The time lapse video contains 3,625 still images. Each second of the movie shows about 5 minutes of changes in the sky. Continue reading The dark side of the Moon

Thundersnow

During the Blizzard of Feb. 8-9, 2013 there were reports of thunder and lightning amidst the heavy snowfall and high winds. The lightning detector on the roof of Ladd Observatory recorded a great deal of activity late Friday night into Saturday morning with the peak occurring just before midnight. Most of the strikes were along the southern coast of Rhode Island, but some were observed about 350 miles to the south over the ocean. For more information about thunder snowstorms see Scientific American.

thundersnow
Plot of lightning strikes detected by our weather station during the Blizzard of Feb. 8-9, 2013. The activity was not as strong as a summer thunderstorm, but was unusual for this time of year and very rare for a blizzard.

2012 Geminid Meteor Shower

The Geminid meteor shower peaked on Dec. 13 – 14, 2012. At Ladd Observatory we operate an automated camera on the roof which takes an image of most of the sky every 10 seconds. There were many small meteors and a number of medium meteors that we captured during the night. Here are the four best images. Each is a 10 second exposure with a field of view of about 140 by 90 degrees. North is at right and west is at bottom.

Watching the skies for meteors

There are some times during the year when a number of meteors can be seen in the sky. For example, the recent Quadrantid meteor shower during the early morning hours of January 4th. But late January is not usually a time that you would expect to see meteors. It is possible, though.

At the Ladd Observatory we’ve been testing a sky camera to watch for interesting phenomena in the night sky. The camera has a field of view of 90 by 140 degrees which can take an image of nearly the entire sky every 10 seconds.

sky camera
The small gray weather proof box in front of the dome on the roof of Ladd Observatory contains a digital all sky astronomy camera which is used to capture images of the night sky.

Continue reading Watching the skies for meteors