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.
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.
“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.”
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.
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.
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.
“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 (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.
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.
The School Committee of the Town of Smithfield submitted a report to the General Assembly of the State of Rhode Island for the school year ending May 1, 1865. One of the challenges conveyed was poor attendance by pupils “… who were suffered to be roaming the streets and fields, when they should have been at school.”
The Committee highlights the success of the school at Lonsdale, the only high school in the town at the time. The principal is praised for his work and it is mentioned that he lends his own personal telescope for use by the students. The school is seen as a model that other school districts should emulate.