Great Blue Hill Observatory

One of the classes I occasionally sat in on this spring was the D-Lab course on Weather, Climate Change and Health. In the class, students worked on projects that could contribute to solving problems at the nexus of, well, weather, climate change and health. Throughout the semester, students took field trips, including building solar trailers to help Puerto Ricans still without power following Hurricane Maria. One of the field trips was an early March sojourn to the Great Blue Hill Observatory.

Located in Milton, about 10 miles south of Boston and not far from Quincy and Braintree, home to former president John Adams, Great Blue Hill is known as “Massachusett” by native Americans. It gained its English name when settlers saw the 635-foot-high granite hill’s blue cast as they approached by ship.

We approached the hill by car and could only see splotches of white (leftover snow) and brown. We parked at the base of the hill, near a small ski slope and a wildlife sanctuary featuring a bald eagle, a snowy owl, a red-tailed hawk, deer and other rescued fauna.

A mulch path led us toward the hill and then gave way to woody trails. Eventually granite boulders, deposited by long-ago glaciers, intervened. We clambered over the rocks and headed toward the top of the hill.

Don McCasland led the way. As program director for the Great Blue Hill Observatory, McCasland was deeply knowledgable about the area. He pointed out quirks in the topography; noted how the flora varied depending on what side of a ridge it was on; and encouraged us to take note of the way the rocks were weathering and eroding.

Panorama from the Blue Hill Observatory platform. Various instruments measure pressure, wind speed, wind direction, temperature, precipitation, and much more.

At the top of the hill stands a small building — the Blue Hill Observatory. Built by Abbott Lawrence Rotch, an MIT graduate from 1882, the observatory began recording the weather on an interrupted daily basis since 1885. That’s 132 years of continuous weather observation — a U.S. record. Not only that, but the observations have been done using essentially the same instruments for that entire period. Using the same instruments means the record doesn’t suffer from errors simply from differing instrumentation. Of course, additional instruments have been added, but the original instruments — or carbon copies of them — continue to be used to this day.

It’s tempting to think the weather instruments of 2018 are vastly advanced over those from 1885. And some certainly are. But then there are those where improvement simply isn’t necessary. Rain gauges simply catch the rain, of course. Mercury thermometers work quite nicely, thank you very much. A crystal ball catches the suns rays and focuses them onto a piece of paper. The more the paper burns under the crystal ball, the brighter the sun that day. What more do you need?

Ultrasonic wind anemometers. Computer-controlled somethings. Webcams. Fancy-pants other things.

The history of the observatory is fascinating, too. , and describes sending enormous kites miles into the atmosphere to take various measurements. Standing on the observation platform, you could easily see Rhode Island and New Hampshire, and probably beyond.

Because it is among the highest points around Boston, it’s valuable for relaying radio and television signals. In fact, WGBH used the hill for just that purpose, relaying its broadcast signal to the New England region. And this is when I discovered the answer to a question that I’ve long wondered. Where do WGBH’s call letters come from? Great Blue Hill.

Now you might ask, doesn’t that make me a ginormous nerd? Yes. Yes it does.

One thought on “Great Blue Hill Observatory

Leave a Reply

Your email address will not be published. Required fields are marked *