Welcome to the Ryerson Astronomical Society

What We Do

The RAS holds a Monday evening talk series during the UChicago academic year, as well as public observation on Wednesday nights. No experience or prior interest is necessary for either event, and we encourage everyone to come and participate. Beyond our weekly events, the RAS conducts many other activities in the astronomy and astrophysics realm, which are open to our members.

Calendar of Events

Club Mission

The Ryerson Astronomical Society (RAS) is the University of Chicago’s astronomy club. Our club’s purpose is to observe the celestial luminaries in hushed awe in our observation dome on the roof of Ryerson Hall, and to spread the love of astronomy and astrophysics through talks and events.

Join us for Wednesday Observation Nights

Majors and non-majors alike welcome. Invite your friends! Join our listhost to stay updated on when we host observation nights.

What is this?

Created by Attilla Danko, it’s the astronomer’s forecast. At a glance, it shows when it will be cloudy or clear for the next few days. It’s a prediction of when Chicago, IL, will have good weather for astronomical observing.

The data comes from a forecast model developed by Allan Rahill of the Canadian Meteorological Centre. CMC’s numerical weather forecasts are unique because they are specifically designed for astronomers. But they have 1180 forecast maps. It can be a chore to find the one map that tells you if you can observe tonight.

So, Attilla Danko wrote a script to generate the images like the one above which summarizes CMC’s forecast images just for Chicago and the surroundings out to about 10 miles.

How do I read it?

Summary: In the rows labeled “Sky”, find a column of blue blocks. You can probably observe then.

Details: Read the image from left to right. Each column represents a different hour. The colors of the blocks are the colors from CMC’s forecast maps for that hour. The two numbers at the top of a column is the time. A digit 1 on top of a 3 means 13:00 or 1pm. It’s local time, in 24hr format. (Local time for Chicago is -6.0 hours from GMT.) Single blocks mean separate forecast data for each hour. Connected blocks mean one forecast calculation for several hours.

Detailed information on cloud cover, transparency, seeing, and more can be found here.