All posts by Michael L Umbricht

I’m the Curator of the historic Ladd Observatory. The Observatory opened in 1891 and is part of the Department of Physics at Brown University. Today it is operated as a working museum where visitors can experience astronomy as it was practiced a century ago. I spend most of my time presenting science outreach and public education programs, demonstrations, and exhibits. I’m also responsible for the historic scientific instrument collection. My primary research interest is late 19th and early 20th century astronomy with a focus on precision timekeeping using mechanical clocks and transit telescopes. Other research includes the early history of wireless and the industrialization of Providence.

Clock vaults

“Owing to the courtesy of Prof. Upton, the laboratory has now the advantage of a set of time signals.”

―Carl Barus, Report of the Professor of Physics. Annual Report of the President to the Corporation of Brown University, June 18, 1896.

The masonry pier that supports the Ladd Observatory’s main telescope contains two clock vaults. These are very small rooms (4 by 4 feet square inside) that contain precision pendulum timepieces called regulators. The purpose of a clock vault is to provide a vibration-free and temperature-stable environment for exact timekeeping. The main clock vault is located in the entrance foyer on the first floor of the Observatory. The basement level vault has not been used in many years. Professor Winslow Upton calibrated the regulators using observations of stars starting in the 1890s.

clock vault
A regulator made by Robert Molyneux in London during the 1850s can be seen inside the main vault on the first floor.

The double doors to the vault seal out drafts and have windows through which the regulators can be observed without disturbing the environment inside. The brick walls are two feet thick which provides insulation to prevent fluctuating temperatures which could cause inaccuracy. There are  telegraph wires to send time signals from the regulators to other locations around Rhode Island. Starting September 12, 1893 and continuing until as late as 1973 the Observatory also transmitted time signals to City of Providence fire stations. Every day at noon and 8:30 p.m. signals sounded on the fire-alarm bells allowing residents and businesses to set their clocks to the correct time. Public time signaling was a common practice during this era.

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Chromospheric lines

“These are some of the problems in connection with the sun which are being investigated at the present time. Their complete solution will help to interpret the mystery, not only of the sun itself, but also of that type of stars of which the sun is a representative.”

―Frederick Slocum, The Study of Solar Prominences. Popular Astronomy, July 12, 1912.

Frederick Slocum (Brown University undergraduate class of 1895) received the first Ph.D. in astronomy at Brown in 1898 and served as assistant professor of astronomy from 1899 to 1909. He then became professor of astronomy at Wesleyan University in 1914 where he planned and supervised the construction of Van Vleck Observatory. The image below shows Slocum observing with a spectroscope attached to the main telescope at Ladd Observatory.

observing with a spectroscope
Observer Frederick Slocum using a spectroscope on the 12″ refractor at Ladd Observatory. March 15, 1905.

This spectroscope was made by the scientific instrument maker John Brashear of Pittsburgh in 1891. It is used to study the spectrum of colors in starlight. It could also be mounted on a table top to examine the spectrum of a chemical which is done to calibrate the instrument. During this era professor Winslow Upton used it in an attempt to predict rain.  It uses a prism or diffraction grating to disperse the light into a rainbow pattern of colors. This reveals dark Fraunhofer lines in the spectrum that can be used to identify the chemical elements present in the Sun or a distant star. Each chemical element has a unique pattern of these dark lines where specific colors are missing.

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Satellite tracking

A Cygnus cargo spacecraft was launched to the International Space Station (ISS) on May 21, 2018. Among the supplies that it carried were nine small educational and commercial satellites know as CubeSats. One of the satellites is named EQUiSat. It was designed and built by Brown Space Engineering (BSE) undergraduate students.

Four of these satellites were released on July 13, 2018 from the ISS by astronauts using a device called the NanoRacks CubeSat Deployer. They were ejected at about 1.5 m/.s (3 mph.) Initially they were spaced about 10 to 50 cm (4 to 20 inches) apart. They quickly moved ahead of the ISS together in a cluster as the distance between them more gradually increased over time. EQUiSat is the second cube from the right.

Deployment of a CubeSat flock
Deployment of a “flock” of four CubeSats from the ISS on July 13, 2018. Credit: NASA

Below are maps showing the ground track of the small satellites as they orbit 400 km (250 miles) above the Earth. Also shown are the paths they take across the sky as they pass above the radio ground station at Ladd Observatory. Traveling at a speed of 27,600 km/h (17,100 mph) it takes only 92 minutes to orbit the Earth.

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EQUiSat 1.0 (and future revisions)

Idea for EQUiSat 2.0: “Hall thruster powered by LiFePO4s – to go to the moon”

―Mckenna Cisler ’20, Brown Space Engineering

It began as a thought experiment for a class in 2011: “Developing a mission plan for a space related project.” On July 13, 2018 that plan became a reality when astronauts aboard the International Space Station (ISS) deployed EQUiSat. Undergraduate students from the Brown Space Engineering (BSE) team had designed and built a “cubesat” which NASA then launched on a cargo supply mission to the ISS in May of 2018. After deployment it started transmitting data from low-earth orbit to an antenna on the roof of Ladd Observatory and another ground station at Sapienza in Rome, Italy. In the words of former team member and class of ’14 astrophysicist Emily Gilbert: “***IT’S ALIVE! IT’S ALIVEEEEE!!!!***

Constructing EQUiSat
Hunter Ray working on EQUiSat in the Brown Space Engineering lab on Dec.10, 2017.

The idea for their mission was to test a new battery technology called lithium iron phosphate (LiFePO4) which had never flown in space.  While all space missions are risky using untested components for an important scientific mission or in an expensive commercial satellite is an unacceptably high risk. The students set out to build an inexpensive testbed to prove this technology. The satellite cost $3,776.61 to build. That price tag doesn’t include the countless hours spent by more than 200 students to design and fabricate the parts of the satellite. NASA agreed to launch the satellite for free. If the results look promising it could lower the cost of future space missions and enable new capabilities.

But the technical requirements of the mission are merely a backdrop for a broader vision. The real goal and larger dream of BSE mechanical engineer Hunter Ray ’18 is “For space to become more affordable and accessible to a community other than astronauts and rocket scientists and to be able to look up at the Moon and see the lights of the first permanent extraplanetary settlement.

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On March 2, 2018 a severe storm impacted southeastern New England. The storm was classified as a Nor’easter which is named for the characteristic strong winds from the northeast. During the storm our weather station recorded fifty-five wind gusts greater than 50 miles per hour. The two strongest were 62 mph at 1:48 and again at 1:50 pm.

Average wind speed and highest wind gusts graph.

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