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Using astronomical observations obtained from the new telescope, Langley devised a precise time standard – including time zones – that became known as the Allegheny Time System. Initially he broadcast time signals to Allegheny city business and the Pennsylvania Railroad. Eventually, twice a day, the Allegheny time signals broadcast the correct time via 4713 miles of telegraph lines to all railroads in the US and Canada. Langley used the money from the railroads to finance the observatory. From about 1868, revenues from the Allegheny Time continued to fund the observatory until the US Naval Observatory provided the signals for free in 1883.

Once funding was secure, Langley devoted his time at the Observatory initially in researching the sun. He used his draftsman skills (from his first job right out of high school) to produce hundreds of drawings of solar phenomena, many of which were the first the world had seen. His 1873 remarkably detailed illustration of a sun spot, observed while using the observatory's 13-inch Fitz-Clark refractor became a classic. It is featured on page 21 of his book, The New Astronomy, but was also widely reprinted – in the Americas as well as throughout Europe.

In 1886, Langley received the inaugural Henry Draper Medal from the National Academy of Sciences for his contributions to solar physics.^[4] His publication in 1890 of infrared observations at the Allegheny Observatory in Pittsburgh together with Frank Washington Very along with the data he collected from his invention, the bolometer, was used by Svante Arrhenius to make the first calculations on the greenhouse effect.