Valley View Observatory Construction Saga

Leo demonstrates the strength of his new dome (AAAP Archives)

Drawing on his organizational skills as a stenographer, Leo Scanlon carefully supervised and documented all elements of the Valley View Observatory project, making it a model of precision engineering and project management. Remarkably, the entire project was completed in just two months and two weeks. Design drawing work began September 8, 1930. "Midnight oil flowed copiously for a week while we imprisoned our ideas upon linen with ink," according to Leo.

The dome would be mounted on a 4-walled "board-and-batten" structure of construction grade pine. The Valley View team fashioned or attached the floor joists and flooring, side wall studding, sheathing, flat roof corners, door and windows. Copper sheathing was cut and soldered to form the flat corners of the roof. The outside walls were given three coats of white lead paint and linseed oil, while the inside woodwork received a coat of dark mahogany stain for the sheathing and dark oak for the studs. Raw linseed oil was applied to the floor for waterproofing, followed by mahogany stain.

Next, the team fabricated the two 12' circular rings that would comprise the track for the rotating dome. Sections of 2" angle iron were cut, bent, drilled and welded to make both the roller mounting frame for the base of the dome, and the matching racetrack on the roof of the wood structure.

With track fabrication complete, the team turned to the critical task of cutting, attaching, bending and coupling the curved dome panels. Thanks to the computations performed by the Carnegie Tech professor, scribing and cutting of the orange-peel shaped panels was straightforward and required no secondary trimming. To assure that each panel was bent over to the proper radius of curvature, the team assembled a movable wooden form having the required shape and dimensions. Each time a panel was bent over the form and coupled to the adjacent panel, the form was moved.

Then came the keynote task of coupling the panels (the point where other observatory designs became complicated). In Leo's own words: "After they had been bolted to the base and bent over the form, the sheets were held in the curved position with C-clamps, while the first turn over on the two upstanding portions of the sheets was made. After this turn was completed up the entire length of the sheet, the whole standing seam was turned down once again, giving it a 'double-turned standing seam,' strong and true, giving an unobstructed dome inside."

Of course, the new dome was useless without a light passage or "slit" for the telescope. A cut was made in the assembled sheet metal to create the slit. Then, curved arcs of wood (milled at a local sawmill) were fastened under the perimeter of the slit to provide reinforcement. The slit doors were cut from the leftover sheet aluminum and reworked to move laterally on brass pipe slide bars. Leo devised an opening/closing mechanism for the slit doors consisting of awning swivel pulleys and sash cord.

Then came the big day when the fully assembled, 250 lb. dome was to be lifted into place. Leo gathered eight moderately muscular fellows to heave the dome up an embankment, across several walkway planks and onto the top edge of the walled structure. The mating of the dome's rollers with the fixed track was a bit nerve-racking, but, Leo noted, "We had no fear it would not revolve, but sent it around slowly for a rev or two, and could not suppress a howl of pure joy when we found everything OK."

With the dome now in place and fully operational, Leo and his friends set about to make the inside of Valley View Observatory a very interesting place indeed. First, the entire inside surface was given two coats of blackboard black paint. Next, each panel was scored with fine white lines to represent the celestial grid down to -20 deg. declination, with each panel representing 2 hours of Right Ascension. Finally, nearly 300 stars were painted on the inside of the dome, representing naked-eye stars down to 3rd magnitude that were typically visible from the Valley View site. (Polaris was placed at the Zenith of the dome, rather than adjusted for Pittsburgh's 40 deg. N latitude.) Thus, the interior of the observatory became a kind of three-dimensional "Star & Planet Finder" for visitors as they awaited their turns to look through the 10" telescope. Leo then installed several light boxes around the inside of the walled area to display back-lit color transparencies of notable astronomical objects (the transparencies were obtained from Yerkes Observatory). Star charts were consulted with the aid of a small table and red lamp at one corner of the room.

Thanks to Leo's meticulous record keeping, we know that Valley View Observatory required 345 hours of total labor and that he contributed 125 hours (35%) of his own time, by far the most of any individual member of the 10-person team. The total 1930 cost of time and materials was $250.11.

Valley View's Other Half

Leo works in the basement workshop of Valley View Observatory (AAAP Archives)

Valley View

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