Which powerful instrument did Edwin Hubble utilize at the Mount Wilson Observatory to settle debates about spiral nebulae?

Answer

The 100-inch Hooker Telescope.

Edwin Hubble used the 100-inch Hooker Telescope, which was the world's most powerful instrument at that time, while working at the Mount Wilson Observatory to investigate the distant nebulae.

Which powerful instrument did Edwin Hubble utilize at the Mount Wilson Observatory to settle debates about spiral nebulae?
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