Twin City Amateur Astronomers

Public Observing Sessions

From April through October, the TCAA holds monthly observing sessions that are open to the public. These "star parties" are held at our observatory at the Sugar Grove Nature Center, a dark sky site southwest of Bloomington.

In 2021, we will hold the following observing sessions Additional prominent sky objects such as planets, nebulae, star clusters, and galaxies will be viewed when visible.

DateFeatured TopicTime
April 17April Public Observing Session08:00PM - 10:00PM
The TCAA will host its first public talk and telescope viewing session for 2021 at Sugar Grove Nature Center on Saturday evening, April 17. Though this is an outdoor event, COVID precautions will be observed. Please wear a mask to this event. If you do not have a mask, one will be provided. Other precautions will be observed as well. Details will be provided at the event.
The session begins with a talk in the picnic shelter at 8:00 PM. If the sky is clear, a brief sky lecture will follow and, after that, viewing of the heavens with telescopes will take place. If the sky is overcast, the event will still be held, whereas the sky observing portion will be canceled. In the event of an overcast sky, our observatories will be opened for inspection. Only in the event of rain will the event be canceled.
Download the public viewing session brochure below for complete details.
May 15May Public Viewing Session08:30PM - 10:30PM
Despite the overcast sky, the TCAA will host a public viewing session this evening at Sugar Grove Nature Center.

Our speaker will be TCAA President Tim Stone. Tim's topic will be


In the spring, our line of sight on the sky looks straight out of our galaxy into the vast depths of space beyond, showcasing thousands of bright galaxies and millions of dim ones. We will tour this neighborhood of the universe, highlighting some of the most beautiful galaxies in the heavens.

The presentation will commence at 8:30 PM and will last 20-30 minutes.

OTHER ACTIVITIES: The overcast sky will prevent sky watching. Nonetheless, we will have open houses at both Sugar Grove and Prairie Sky Observatories following the presentation.

COVID PRECAUTIONS: Out of an abundance of caution, attendees are requested to wear face masks. Face masks will be available in adult and child sizes should they be needed.
June 12Navigating with Stars09:00PM - 11:00PM
For centuries, navigators have relied on stars to identify directions, compute latitude, and even read local time. We will explore these ideas and examine the problem of measuring one’s longitude at sea – a fascinating problem that defeated some of the best minds in the world for many years.
July 10Venus & Mars Tonight08:30PM - 12:00PM
The TCAA talk and observing session for this evening, Saturday, July 10, at Sugar Grove Nature Center has been canceled due to intermittent rain and rain in the evening forecast.
August 14Our Amazing Moon08:30PM - 10:30PM
The moon has many regular features and changing appearances. Learn about our nearest neighbor in space and observe the 5-day-old moon through a telescope.
September 11The ISS: Past, Present, and Future07:30PM - 09:30PM
The International Space Station has been orbiting Earth since its launch in 2000. Since that time, millions of Earthlings have seen it course across our morning and evening sky. If you’ve never seen it, learn where, when, and how to do so.
October 09Jupiter & Saturn07:00PM - 09:00PM
Jupiter and Saturn offer stark contrasts when compared to the inner planets. We will review how and why they formed in their current locations and their impact on the formation of the rest of the solar system. We will learn how the two greatest planets are similar yet different.

A Typical Public Viewing Session includes:
  • Lecture about the featured object.
    This 20-30 min. presentation, held in the SGNC picnic shelter, includes images of and details about the featured sky object as well as information on other interesting celestial objects that might be viewed that evening.
  • Sky tour using a laser pointer.
    We step out under the stars to point out the major constellations and planets, and to designate the location of the featured celestial object for the evening.
  • Telescope observing session.
    We use members' telescope at ground level to observe the featured object and other wonders of the heavens.

You can download our 2021 Public Viewing Session brochure.

If you would like to arrange a special event for your group, please follow this link to Request a Special Event.