The Chicago Astronomical Society (CAS) holds monthly meetings and programs on the 2nd Friday of the month, at Adler Planetarium. Meetings start at 7:00 PM. Board meetings are held the Third Friday of each month (except when a holiday or special circumstances interfere); they are held at Triton College in River Grove (at the Cernan Earth and Space Center).We conduct public observing sessions at a number of sites. The CAS annually hosts the Astrofest star party in September.

Elections are held every June. CAS officers elected are: President, Vice-President, Secretary, Treasurer, Directors-at-Large, and Observatory Director. Feel free to attend our meetings. If you want more information or have questions, please contact us or call our voicemail, (773) 725-5618, and leave a message (please speak slowly and clearly). We will try to respond as soon as possible (please be patient; there are delays occasionally).

The Chicago Astronomical Society welcomes people interested in astronomy to join our organization. We offer a variety of membership options as shown below. Privileges associated with each category are noted. Privileges include the right to vote; to receive the CAS newsletter, the "Observer", and the publications of the Astronomical League (AL), of which CAS is a member: "Reflector" and "Northern Lights". Qualifying members may also subscribe to "Sky & Telescope" and/or "Astronomy" Magazines at the club discount rates of $32.95 and $34.00 respectively (rates as of 03/04; these rates are subject to change). To get any, or both, of these magazines add the club discount price to the appropriate membership dues amount when writing out the check.

• Regular member: votes; receives AL publications and CAS newsletter. The yearly fee is $30.00.
• Student member: votes; receives the AL publications and CAS newsletter. The yearly fee is $17.00.
• Associate member: votes; no publications or CAS newsletter. The yearly fee is $13.75. To qualify, you must live in the same household as an individual benefactor, patron, regular, or student member.
• Patron member: votes; receives AL publications and CAS newsletter. The yearly fee is $250.00.
• Benefactor member: votes; receives the AL publications and CAS newsletter. The fee is $1000.00 for an individual benefactor and $1000.00 for a corporate benefactor. An individual benefactor becomes a lifetime member and a corporate benefactor is a member for 50 years.
• Affiliating member: only gets the CAS newsletter. To qualify, you must be a voting member of another recognized astronomical organization. The yearly fee is $18.00 for members of domestic organizations and $20.00 for members of foreign organizations.
• Corresponding member: only get the CAS newsletter. To qualify, you must live outside the state of Illinois. The yearly fee is $18.00 if you live in the United States and $20.00 if you live outside the United States.