Fr. Walter Sidgreaves (1837 - 1919)

 

Fr. Walter Sidgreaves, SJ., FRAS, (1837-1919) was born 4th October 1837 at Grimsargh, near Preston, and first went to Stonyhurst as a boy in 1848 to study theology. After joining the Society of Jesus in 1855, he taught chemistry and mathematics at Stonyhurst and became acting director of the observatory in the period 1863-68 during the time that his superior, Father Stephen Joseph Perry (1833-1889), another of the Stonyhurst priest-astronomers, was engaged in his own theological studies. Along with Father Aloysius Laurence Cortie (1859-1925), who also had close ties with Manchester, Walter Sidgreaves at the time of his becoming first president of the North Western Branch was already a significant contributor to the amateur-lead science of astronomy in the UK. His close friend and colleague, Father Perry had eleven years earlier in 1881 become first president of Liverpool Astronomical Society.

Stonyhurst observatory was founded in 1838 and was primarily intended as a meteorological station. It became one of seven key UK stations when the Meteorological Office came under the auspices of the Royal Society, thirty years later. Under the direction of Fathers Weld, Perry and Sidgreaves, the observatory rapidly expanded to include astronomy, geomagnetrometry and seismology into its scientific curriculum. In 1858, Sir Edward Sabine, who was making a magnetic survey of England, chose Stonyhurst as one of the main observing stations and it was Sidgreaves who, in 1863, inaugurated the first regular series of monthly geomagnetic observations. In 1866 he installed a set of self-recording photographic magnetographs, donated by the Royal Society, in a specially constructed underground chamber. He continued the monthly magnetic observations uninterruptedly until May 1919, the month prior to his death.

In 1848, the year in which Sidgreaves first attended the college, the Italian astronomer, Father Angelo Secchi, of the Jesuit Collegio di Romano Observatory, in Rome, had stayed at Stonyhurst, in retreat from revolutionary troubles in Italy. Stoneyhust's astronomical leanings, particularly in solar observation, apparently stemmed from his time in residence. Following pioneering work in the late 1850's by Bunsen and Kirchhoff in the spectroscopic analysis of laboratory chemicals, and their early examinations of the solar spectrum that lead to an understanding of the dark absorption lines, Secchi was the first to classify stars into their spectral types in the early 1860s. Together with Lockyer and Huggins, Secchi went on to play an important role in the study of solar and stellar physics. Sidgreaves own original researches of the solar spectrum are contained in many papers published in the Monthly Notices of the Royal Astronomical Society. In solar physics he made a long photographic study of the sun, including hundreds of photographs taken in the violet light of calcium, using a Hilger spectroscope acquired by Father Perry. In this research he showed that the sun is spectroscopically, a variable star.

During his time as president of the Branch, Sidegreaves carried out original work into the spectroscopy of novae. His work on Nova Aurigae, in 1892, contained some of the first photographs of the spectra of novae ever taken. He recognised in them the similarity between the spectrum of the new star and that of the solar chromosphere, rich in the pink light of ionised hydrogen. Equally significant results were obtained with the spectrum of Nova Perseii, in 1901.

Sidgreaves was particularly interested in the connection between sunspots and fluctuations in earth's magnetic field. He published several papers on the subject based on observations made at Stonyhurst. In work carried out between 1881 and 1898, he came to the conclusion that although magnetic storms were not directly a result of sunspots, they were due to clouds of electrified particles moving between the sun and earth. We now know that solar mass ejections caused by solar flares can interact with the earth's magnetic field to produce magnetic storms. They are now of great importance, having been known to disrupt national power-grids and cause expensive damage earth-orbiting telecommunication satellites.

During 1874 vessels of several nationalities made visits to the remote Kerguelen Island in the southern Indian Ocean in connection with the observation of a transit of Venus across the face of the Sun predicted for 9th December of that year. The United States expedition, under Commander G.P. Ryan arrived on the U.S.S. Swatara on 7 September and installed an observatory at Pointe Molloy. The German expedition of 1874 to 1876 under Commander Baron von Schleinitz arrived at Anse Betsy on 26 October 1874 in the Gazelle and established astronomical and magnetic observatories while T.Studer made a geological reconnaissance of the Courbet peninsula. A British expedition, lead by S.J. Perry, arrived at Baie de l'Observatoire in the Volage on 5 November 1874 and established two magnetic and astronomical stations at Observatory Bay and at Thumbed Peak.

Thirty-six year old Walter Sidgreaves accompanied Father Perry, five years his senior, on the British Government expedition. On 8th October 1874 they were taken from the Cape of Good Hope aboard the sail-assisted steamship, HMS Volage, to the desolate island that was to be their home for over four months, until 27th February 1875. Sidgreaves was responsible for setting up most of the equipment and was wholley responsible for the magnetic observations. Rabbits liberated on the island by the British expedition subsequently destroyed much of the lowland vegetation and totally changed the look of Kerguelen.

He again accompanied Perry, who by this time had become president of Liverpool Astronomical Society, to observe a second transit of Venus, in 1882, from Nosy Faly (Faly island), Madagascar.

On the death of Father Perry aboard HMS Comus, during the total solar eclipse expedition to Cayenne, in French Guiana, South America, in December 1889, Father Sidegreaves assumed charge of Stonyhurst Observatory. He was already Superior to the scholasticate and since 1883 had held the office of professor of experimental physics. His professorship lasted twenty-two years.

Stonyhurst observatory, under the directorships of Father Perry and Father Sidgreaves, had been continually upgraded. The 4-inch refractor used by Secchi was replaced in 1867 by an 8-inch refractor. This was replaced in 1894 with a Grubb 15-inch refractor, as a memorial to Father Perry. [i] [ii]

Kevin Kilburn, F.R.A.S.

 

References

[i] Sidgreaves, Walter. Obituary Notice. Monthly. Not. RAS 80.Nov-Oct 1919-20. pp 355+
[ii] Chapman, Allan. 1998. The Victorian Amateur Astronomer. Wiley-Praxis.


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