1. Visual Observation:
* Telescopes: The primary tool was the optical telescope, which had advanced significantly since the 17th century.
* Refracting Telescopes: Used lenses to focus light, offering sharp images but limited in size due to the weight of the lenses.
* Reflecting Telescopes: Used mirrors to focus light, allowing for larger sizes and thus greater light gathering ability.
* Naked Eye Observations: Many astronomers still relied on visual observations with the naked eye for certain tasks, like charting the position of stars or observing meteor showers.
* Charting and Measurement: Astronomers meticulously recorded their observations by hand, creating detailed star charts and measuring distances and positions using tools like sextants and astrolabes.
2. Photographic Techniques:
* Astrophotography: The use of photographic plates was revolutionizing astronomy.
* Long Exposures: Capturing the light from faint stars and galaxies required long exposures, sometimes lasting for hours.
* Spectral Analysis: Photographs of starlight could be analyzed to determine the composition and temperature of stars.
3. Spectroscopy:
* Prisms and Spectrographs: By passing starlight through a prism or spectrograph, astronomers could break down the light into its individual wavelengths, revealing spectral lines.
* Spectral Classification: This allowed scientists to classify stars into different types based on their temperature and chemical composition.
* Doppler Shift: Spectral lines could be used to measure the movement of stars towards or away from Earth using the Doppler effect.
4. Limitations and Challenges:
* Limited Data: Data collection was slow and laborious, often reliant on visual observations and photographic plates.
* Manual Calculations: Analyzing data and performing calculations relied heavily on manual methods, requiring significant time and effort.
* Limited Understanding: Although significant progress had been made, much about the universe remained unknown, such as the true scale of the Milky Way or the nature of galaxies.
In Summary:
100 years ago, astronomy was a meticulous and laborious field, heavily reliant on visual observation and photographic techniques. While technology was less advanced, the ingenuity and dedication of astronomers laid the foundation for the immense leaps in knowledge we've seen in the past century.
