

The Summer Issue of our Quarterly Newsletter, Reflections is Now Available Online.

Click here to read the Summer issue of our newsletter and get a quick update on our status during the pandemic.

The feature article is the second part of the story of how Mount Wilson astronomers measured, for the first time, the size of a star (other than the Sun). This monumental achievement was made in the fall of 1920, nearly one hundred years ago. To read the first part, see last December’s issue of Reflections here. The followup article in this issue details how Walter Adams, the second director of the Observatory, figured out how to measure distances to thousands of stars, a prerequisite to determining their sizes. When Mount Wilson Observatory was founded, only about 60 stellar distances were known. Adams developed a whole new way to determine distances to stars called spectroscopic parallax. It became an essential rung on the “cosmic distance ladder,” by which astronomers measure the Universe. While Hubble’s work is relatively well known, these two articles offer a good introduction into some of the more obscure ways that astronomers on the mountain used astrophysics to revolutionize their field.

Our Executive Director, Tom Meneghini, updates us on the 100-inch Telescope shutter repair and our current state of affairs. There is also a short article on the Snow Solar Telescope renovation and a big thank you to our 2020 supporters.