top of the telescope tube, was just as it was in the 1950s when Gerard de Vaucou-leurs made his pioneering observations of southern galaxies. I used the camera to take photographs of nearby galaxies in order to measure profiles of their brightness.
Determining the brightness of features on photographic plates is a rather messy and imprecise art. The efficiency with which the older emulsions on photographic glass plates stored photons was not high and we had to soak the plates of glass in nitrogen gas to increase their sensitivity. Even with the relatively fast f/4 focal ratio of the Newtonian focus, long exposure times were needed to acquire photographs with a good tonal range.
After the photographic plate was exposed and carefully developed by hand, the distribution ofdensities of light within the galaxy image could be measured using an instrument known as a microdensitometer, and it was at that point that the real analysis began.
It is fitting to remember that the man after whom the telescope is named - John Reynolds - had conducted his pioneering measurements oflight profiles from photographic plates way back in 1913, using essentially the same telescope configuration at his "Low Wood" observatory, before that telescope was donated to Mt. Stromlo.
Acquiring a good photograph was an adventure. Those were eyeball days. Some words ofclarification. In today's modern era, astronomers track stars as the Earth rotates, by means ofautoguiders. An autoguider can keep a telescope "locked on" to a bright star for hours.
Not so easy, guiding the telescope by eye.
To access the camera at the top end of the Reynolds telescope, the observer was perched on a rickety 2-m wooden stepladder which the observer had to drag around the dome as the telescope tracked across the sky. The camera itself com-Shrouds of the Night prised a microscope and photographic plate-holder mounted on a structure that
The observer first pointed the telescope at a desired galaxy and then moved the microscope around to find a guide star (in other words, a star which the telescope would remain fixed on, as the Earth rotates). Then the exposure would begin.
The telescope mechanism was far from perfect and constant adjustment was essential. For two or three hours, the observer would keep an eye glued to the microscope and both hands on the adjustment screws that moved the plate holder. If the guide star drifted as the telescope tracked across the sky, the observer moved the plate holder to keep the star central in the microscope. Each hour, the observer had to close the shutter, climb down from the ladder and manually rewind the main gear drive. The goal of every observation was to produce a guided photograph of the galaxy with perfectly round stellar images.
Each exposure was a battle between the observer and the old worn-out telescope gears, with the observer visually guiding the plateholder through the microscope, as the telescope tracked erratically across the sky.
Although the photographic process was notoriously unpredictable, an amazing amount of semi-quantitative astronomy was accomplished. There were some failures but everything mostly worked out well. We all had to develop photographic skills, because we had no other panoramic detectors until the early 1980s when the first of the digital charge coupled devices (CCDs) became available.
Data acquisition and analysis then became much easier and a new era ofquan-titative astronomy began. I was not sorry to see the end of photography in astronomy, although I know my coauthor David deeply feels otherwise!
John Hart, Head of the Opto-Mechanical Engineering Section at the Mount Stromlo Observatory, recalls that the Reynolds telescope was very antiquated with decorative holes in a spherically shaped counterweight at the back of the mirror cell (these decorative holes are clearly visible in Figure 116). We replaced many parts (during 1969-1971) and remachined the base and the center section of the tube. Design and construction progressed in parallel. The existing mirror was fitted into a new mirror cell. I was a very new engineer at the time and was overawed by the responsibility of the job, which took a couple of years in total. I was in charge of the entire refurbishment. I was the only designer and had about six laboratory craftsmen in the workshop. Among the astronomers I met who used the Reynolds telescope were Gerry Kron, Ben Gascoigne and Allan Sandage. Sandage only used the Reynolds telescope a couple of times but seemed very happy with it.
Astronomer Ben Gascoigne (Figure 121) - now long retired from the staff from Mount Stromlo - was allocated nine months of observing time on the 30-inch Reynolds telescope in the early 1950s and recalls his experiences:
Time was when you worked alone, the telescope all to yourself, in the total dark, and in winter-time slowly freezing to death. But no matter how cold it had been, how difficult, or how successful for that matter, it always ended, dawn came along and you walked home, the sky all pink in the east, the birds tuning up for the day ahead, and just for a little while the world belonged to you. Nothing else I have known was quite like it, and only astronomers have experienced it.
The Reynolds telescope was used by some of the world's foremost galaxy experts of the era, including the late Gerard de Vaucouleurs. Between 1952 and 1955, de Vaucouleurs secured about 250 one-hour exposures of galaxies in the southern skies from Mt. Stromlo. The generosity of John Reynolds was indirectly crucial to the development of the galaxy classification criteria developed by Gerard de Vaucouleurs, as is clearly evident in "Memoirs of the Commonwealth Observatory No. 13" published in July 1956. The seeds of the de Vaucouleurs classification system (discussed in some detail in Chapter 11) were clearly born, in part, using the scores of galaxy photographs which Gerard de Vaucouleurs painstakingly secured in Canberra with the 30-inch Reynolds reflecting telescope.
Reynolds was an individual with enormous vision, and Hubble recognized this. It would be no overstatement to say he was England's foremost observational expert on the morphology of the nebulae, but the letters between Hubble and Reynolds have hitherto never been published.
In Figure 122 appear sections of a letter in the hand of Edwin Hubble. The letterhead is the Randolph Hotel, Oxford, written during one of Hubble's visits to England, and commences "Dear Reynolds." To show the exceptional esteem in which Hubble held Mr. Reynolds on the classification of spirals, we read in Hubble's words:
All suggestions on this difficult subject, coming from one of your expertise are extremely welcomed ... Could you not throw your ideas into the form of a precise classification so we could actually apply it to a large number of nebulae representing the various sizes and degrees of brightness with which we will be dealing?
These are only passing thoughts which I offer The great thing is that the discussion is started. This will eventually lead to something acceptable to us all. Sincerely, Edwin Hubble.
Hubble's actual letter from Oxford is undated, but we know that Mr. Reynolds rose to the occasion in 1920. Six years prior to Hubble publishing his classification scheme in 1926, Reynolds devised seven bins or classes pertaining to the shapes of galaxies, which was published in volume 80 of the Monthly Notices of the Royal Astronomical Society.
Of these Reynolds classes, Sandage comments:
Reynolds types I through VII are clearly identical with the Hubble spiral types Sa, Sb, early Sc, and later Sc. The correspondence is one-to-one.
Sandage is recognizing that while Hubble has three spiral types a, b and c, the type c bin spans a wide range of shapes, which Reynolds had taken full cognizance of by proposing his classes I to VII.
The question before us is therefore, was Hubble aware of the classification scheme devised by Mr. Reynolds in 1920, prior to publishing his seminal classification paper in 1926? The answer is a resounding ... yes!
In the Reynolds archives housed at the Royal Astronomical Society, Burlington House, we found a copy of a memo from Hubble, dated July 1923, sent to Vesto Slipher as president of Commission 28. Slipher distributed the memo to members of the Commission. The front page of the memo contains the signature of J.H. Reynolds. In that unpublished memo, entitled "The Classification of Nebulae," Hubble writes to Slipher:
The published suggestions of J.H. Reynolds are thoroughly sound ... Reynolds introduced the term amorphous, emphasizing the unresolvable character of much of the nebulosity in non-galactic objects ... Reynolds (ref. 17) has formulated seven classes of true spirals ... the first five classes represent a series with increasing degree of condensation in the amorphous matrix of the outer arms ...
Reference 17 in Hubble's 1923 memo is none other than the paper of Reynolds, contained in volume 80 of the Monthly Notices of the Royal Astronomical Society. It is abundantly clear that Hubble was fully aware of, and had very carefully studied, the classification scheme of Reynolds proposed in 1920. Although fully referenced in the 1923 memo to Slipher, Hubble moves on to publish his 1926 classification without any reference to the source of his classification bins ... the classes of J.H. Reynolds.
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