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 research is primarily on late 19th and early 20th century astronomy with a focus on precision timekeeping using mechanical clocks and transit telescopes.
Note: this was originally published on March 6. It was updated on March 8 to include new information.
On March 6 we received local reports that the aurora was observed in New England just before sunrise. One of our visitors described seeing it from a rest area on Route 495 near Boston. There was another report from Vermont. Our automated all sky camera was running the entire night and captured the view above Providence. Also visible is the International Space Station (ISS) streaking through the sky about 500 miles from Providence as the planets Mars and Saturn shine brilliantly in the south.
During the night the camera recorded 3,750 images of the sky. North is at right, west at bottom, and the zenith is at center. The field of view is about 140 by 90 degrees, capturing most of the sky above Providence. The images can be processed to produce a time lapse movie that shows 5 minutes of changes in the sky per second of video. Click on the image below to watch an excerpt. A number of artificial satellite can be seen streaking through the sky just before dawn.
A Near-Earth Object is an asteroid or comet that is in an orbit that sometimes brings it close to the Earth. The largest of these are known as Potentially Hazardous Objects as they could cause significant damage if they impacted our planet. There are sometimes news reports of a “close approach” where an object passes particularly near the Earth. An asteroid called 2013 TX68 will pass the Earth on March 8, 2016. It is estimated to be 100 feet in diameter.
“An Astronomical Blunder. — Professor Waltemath of Hamburg recently announced through a private circular that he had discovered a second moon to our earth. The contents of the circular were the basis of sensational articles in leading newspapers… He also quotes descriptions of strange objects in the sky seen at various times since the sixteenth century, which his calculations show were probably this second moon.”
Georg Waltemath made an extraordinary claim: that the Earth had a second moon. It was supposed that it was much smaller and dimmer than the known moon. He calculated that this object orbited the Earth every 119 days and would pass between the Earth and Sun, on average, every 177 days. He predicted that on February 3rd of 1898 it would be visible in silhouette as it moved across the disk of the Sun, an event known as an astronomical transit.
“Prof. Winslow Upton, of Brown university, one of the most learned astronomers in the country, has been busily engaged at the Ladd observatory, making photographic exposures of the constellation Perseus, in which the new star appears, and has given out an interesting statement concerning the unusual event. He says:”
– “Catastrophe of tremendous import believed to have caused appearance of bright new star.” The Detroit Free Press, Feb. 27, 1901.
“The appearance of this brilliant star is a rare astronomical event, not equaled in the memory of anyone now living. In fact, no similar event has occurred since the time of Kepler in 1604.”
“The term ‘new star’ or ‘Nova’ is applied to stars which unexpectedly increase their brightness and then fade out again. It is not supposed that any of them are new creations, since those whose histories are best known have been observed as faint stars before the outburst which made them famous. Probably every year witnesses occurrences of this kind, but unless the increase of light is very pronounced it may not be detected among the great multitude of stars.”Continue reading “A catastrophe of stupendous import”→
“I have intrusted Mr. Winslow Upton with the work of compiling the accompanying circular of information relative to time-balls, and have the honor to present herewith the results of his labor.”
– Cleveland Abbe, “Information Relative to the Construction and Maintenance of Time-Balls.” October 1881.
Winslow Upton was a “computer” (in the sense of one who computes) at the U.S. Naval Observatory in 1880. The following year he went to the U.S. Signal Service where he was tasked with compiling a summary on the practice of using time-balls for the distribution of accurate time.
The practice of dropping a ball at exactly noon every day was used to calibrate the chronometers on ships in a nearby harbor. These accurate timepieces were then used for celestial navigation. The balls were installed on tall buildings within a couple of miles of the docked ships. An example is the Boston Time-Ball. The procedure used in Boston was described by B.M. Purssell of the Signal Corps in Upton’s compilation. Continue reading The Boston Time-Ball→
“During the greater part of the year the 3-inch transit instrument has been in the hands of the maker, Mr. G. N. Saegmuller. This instrument, while a fairly satisfactory instrument, was not of such superior excellence as the builder expected it would be. He therefore, without any suggestion on my part, offered to rebuild it without expense, which he has done at considerable cost to himself, and it is now a very superior instrument.”
During the 2010 restoration of the transit room we went to great lengths to ensure that the colors used were historically accurate. The George N. Saegmuller transit telescope had been painted black at some point. We suspected that this was not original but it is impossible to tell from the black and white archival photographs. Continue reading Mid Brunswick Green→
In 1916 Brown University announced that it would soon offer a course teaching students about a new technology: practical and experimental wireless telegraphy. It was more common during this era to transmit messages by radio waves using Morse code. Voice communication and broadcast radio did not become common until the 1920s. Continue reading A fine aerial→
“A very valuable Howard clock has recently been placed in the Steward’s office. It is regulated by Ladd Observatory standard time, and is thus kept as near correct as possible. The clock is connected with the bell-ringer’s room, so that now the college bell will be rung at exactly the right time, doing away with the nuisance and inconvenience often caused last year by the bell being rung too soon.”
“In appearance the clock is very attractive. The case is of handsome oak, and is about three and one-half feet high. It will undoubtedly be a great convenience to the students and will be used by many for regulating their own time pieces.”
Ladd Observatory placed an order on behalf of Brown University for one #89 Regulator on Sept. 13, 1895 . The clock was manufactured by E. Howard & Co. at a cost of $100 and was shipped to Providence on Sept. 25 where it was installed in the office of the Steward. The position of Steward was held by Archibald Grant Delaney from 1884-1904. His office was 1 University Hall. A telegraph break circuit connected the clock to the college bell in the tower of the building. It was regulated to the correct time by comparing it to the precision timepieces at the Observatory. Continue reading Steward Delaney’s New Clock→
“This summit is near the intersection of Hope Street and Doyle Avenue. If in existence in 1835, Hope Street was a rough country road known as East Pawtucket Turnpike. Doyle avenue was not laid out until many years later. On this summit stands Ladd Astronomical Observatory of Brown University erected in 1891.”
When the construction of Ladd Observatory began in May of 1890 the area was rural with few buildings nearby. At a distance to the east and northeast of the hilltop were low lying areas that were swampland, as indicated by the blue hash marks on the map above. These marshes were later drained and filled to allow for building the residential neighborhoods that are seen there today. A short distance to the south there was a large reservoir, built in 1875. A steam powered pumping station delivered the water through pipes buried beneath the streets. The former reservoir is now the site of Hope High School and the athletic fields behind the building. Continue reading Development on the summit→
“In addition to helping the crew organize its time, the second HP-41 computer was kept ready for flight-critical, deorbit-burn calculations. Once during each orbit around the Earth, the shuttle has an opportunity to land at one of six contingency locations. During a routine flight, Mission Control supplies the shuttle crew with deorbit-burn information. Should the shuttle encounter an emergency, however, the astronauts would rely on the HP-41 for these calculations.”
– “HP-41’s Again Aboard Columbia.” HP Key Notes, March-May 1982.
To prepare an orbiting Space Shuttle for re-entry through the Earth’s atmosphere it is critical that the spacecraft be “balanced” by taking into account the mass of the fuel left in the tanks at the end of a mission. An astronaut would use a handheld computer or programmable calculator to determine how many minutes and seconds of fuel to burn to get the center of gravity correct for a smooth descent and landing. The “personal computing system” used for this was made by Hewlett Packard in the 1980s. NASA donated one of these, a model HP-41CV, to Ladd Observatory after the retirement of the Shuttle program. Continue reading Flight-critical calculator→