Nebraska Astronomy Applet Project ClassAction Project

Recent News

Native Apps Update

New versions of executables for Windows and Macintosh OS are now available on the Downloads page. These include packages for NAAP simulations (now with background pages included), ClassAction, and the Interactive Ranking and Sorting Tasks. There will likely be one more update.

Thursday, January 30, 2020  —  Kevin

Flash Alternatives for ClassAction and NAAP

Flash will be removed from the web in 2020. Already web browsers are making it more difficult to use. We are pleased to announce that ClassAction and the NAAP labs are now available as native apps, for both macOS and Windows (they must be installed on your computer). These apps provide an offline alternative that does not require a browser plug-in.

Visit the downloads page at to get the ClassAction and NAAP Labs native apps. Download and run the appropriate files for your system and follow the prompts to install the apps. On Windows, the apps will appear under the AstroUNL folder in the Start Menu. On macOS, the ClassAction and NAAP Labs apps will appear in the Applications folder.

The ClassAction app is nearly identical to the online version. The NAAP Labs app is a work in progress. Currently it includes just the simulations and background interactives. We plan to include the background text so that the entire project will be self-contained. Between these two apps all simulations on the Simulations List Page are now available for use offline, without a browser.

Thursday, October 31, 2019  —  Kevin

Registration Open for Fall Workshop at UNL

A large workshop will be held for high school and college instructors of Physics and Astronomy at UNL on October 12, 2019. The workshop will be a joint meeting of the annual Astronomy Education Workshop and the fall biannual meeting of the Nebraska chapter of the American Association of Physics Teachers. Registration and continental breakfast begin at 8:30 am in Jorgensen Hall and the event will run until 4:30 pm.

Guests include:

  • Robert Hilborn (Associate Executive Officer of the AAPT) — who will be delivering a plenary on the nature of gravitational waves and teaching a longer session on implementing computation in physics classes. He will lead a breakout session on the Living Physics Portal -- a vast repository of teaching materials for IPLS (Introductory Physics for Life Science) students debuting soon.
  • Kathryn Williamson (Teaching Assistant Professor at West Virginia University) — who wil be delivering a plenary on incorporating networks of robotic telescopes in instruction and delivering a longer session on the Pulsar Search Collaboratory.

Attendees can choose between a large number of breakout sessions and three longer sessions. Continental Breakfast, Lunch, and parking are provided.

Registration is available at A flyer describing the event is available at

Attendees who are interested in leading one of the half-hour (interactive) breakout sessions should e-mail Kevin Lee at

Thursday, August 1, 2019  —  Kevin

New Demonstration Video

A new video entitled Eclipses 1: Shadows & Scale has been posted. It has both an embedded peer instruction question and an accompanying worksheet. The video is available on the Astronomy Demonstration Videos Home Page and on YouTube.

Tuesday, May 14, 2019  —  Kevin

Sun Glare at Audi Field

Earlier this year physics undergraduate Brandon Harper began working with ESPN to solve a sun glare problem occurring at the new Audi Field in Washington D.C. During the broadcast of a soccer game last fall, a distracting glare due to the October sunset greatly interfered with the viewing of the game. The goal of the project was to determine when and if the sun could cause more problems like this during future games for the cameras located on the east side of the stadium. From photo and video evidence, the glare last October 13 lasted from about 5:00pm to 6:10pm when the sun finally set below the stadium walls with respect to the cameras. The glare was at its worse at around 5:50pm. The azimuthal and altitudinal coordinates of the sun were determined for that time using Stellarium (Az: 252°16' and Alt: 8°48'), allowing reference to the problematic position when checking dates for the 2019 season. It soon became clear that the azimuthal coordinate may not have an effect on the likeliness of a glare, as the sun will set year-round behind the uniform wall of the stadium, and the camera must be allowed to pan across the entire field. This left an emphasis on investigating the altitudinal coordinate of the sun during its setting. A video of the sunset as viewed from the camera stand was recorded in early March this year, allowing conclusions to be drawn by comparing it to the glare event and using Stellarium to check the coordinates. The problematic altitude of the sun was found to occur consistently about one hour before sunset each day, where the glare could be an issue 1.5 to 0.5 hours before sunset, drawn from the duration of the glare. The conclusion reported to ESPN was that they should be concerned about glare in their broadcast when filming on a clear day anywhere between 90 to 30 minutes before sunset on a given day. The ESPN crew in Washington D.C. was able to take this general rule away from the project and they are applying it to the future of sports broadcast at Audi Field.

Tuesday, April 30, 2019  —  Kevin