2025-10-24 Chat and AI-Generated Summary

Showing Off the Solar System To Young School Groups

(and Occultation Adventures in the Solar System)

with Richard Nolthenius

Video LINK

Below you can find a list of attendees, a copy of the chat, and an AI summary.

To see a description and schedule of all upcoming Planetarians' Zoom Seminars, visit https://www.ppadomes.org/events/online-seminars/pzs-schedule

Date and time for the next seminar:

Planetarium Educators Workshop, Module 2: A Framework for Examining Planetarium Programs, with Alan Gould. 2025 Nov 21 (3rd Friday) at 2pm PDT (5pm EDT, 22:00 UT).

Below

• Attendees

• Chat

• AI-generated Summary

Attendees

1. Rosemary Walling (co-host), Marie Drake Planetarium, Juneau, Ak

2. Mary Holt (co-host), Berkeley, California

3. Andrew Buckingham, Auckland, New Zealand

4. Guilherme Frederico Marranghello, Bagé, Brazil.

5. Jeff Nee, Pasadena, CA

6. Karl von Ahnen Santa Cruz Mountains, California

7. Cristina Della Rosa, Marie Drake Planetarium

8. and a few more

Chat

(The timestamps below are roughly 30 minutes ahead of the corresponding times in the video. )

00:37:51 From Karl von Ahnen": Excellent, Rick! Very sorry I have to leave early. I will watch the video recording.

00:42:39 Jeff Nee: Double Asteroid Redirection Test

00:43:46 Guilherme Frederico Marranghello: I googled "Dart mission" and it really collided with the browser.

From Rosemary Walling (PPA): You're right!

00:56:21 From Mary Holt: Apologies if you already said this at the beginning - but how much of this presentation is what you show in planetarium shows and how much was just for this presentation?

00:59:44 From Guilherme Frederico Marranghello: I have to leave. Thanks for the talk! Have a great weekend!

00:03:36 From Mary Holt:  Well a lot of the images in planetarium software are actual photos to be fair

00:15:22 Nick Strobel: Thank you for the talk!

0015:55 From Amie Gallagher: Thanks for the talk!

AI-generated Summary

This AI-generated summary has not been edited for accuracy nor does not replace watching the full video. If you find any incorrect or misleading information in the AI summaries, you can let us know. Our contact information is here.

Overview

This presentation focused on planetarium education techniques and asteroid occultation research. Rick Nolthenius, Department Chair of Astronomy at Cabrillo College, shared his approach to engaging young audiences in a basic A3P planetarium and discussed his professional work studying asteroids through occultation observations. The talk demonstrated how to create engaging educational experiences with limited equipment while also highlighting the scientific value of asteroid occultation research for determining asteroid properties and supporting NASA missions.

Key Concepts or Theories:

• Interactive planetarium education techniques for engaging young audiences

• Asteroid occultation methodology for determining asteroid properties

• Binary asteroid systems and their scientific importance

• Kuiper Belt object research, including rings and moons around Quaoar

• Practical applications of occultation data for NASA missions

Important Questions Raised:

• How can planetarium educators create engaging experiences with limited equipment?

• What scientific value do asteroid occultations provide that even large telescopes cannot?

• How do binary asteroids help determine composition and density of asteroids?

• Why do some objects like Quaoar have rings beyond the Roche limit when theory suggests they shouldn't exist?

• How can amateur astronomers contribute to high-value scientific research?

Key Takeaways

• Engaging planetarium shows can be created through interactive presentation styles and colorful visuals even with basic equipment

• Asteroid occultation observations provide higher precision measurements than even the largest telescopes can achieve

• Binary asteroid systems allow for mass calculations that help determine asteroid composition

• Occultation data directly supports NASA missions by providing precise positioning and identifying potential hazards

• Amateur astronomers with modest equipment can contribute meaningful data to planetary science

Topic 1: Planetarium Education Techniques

Rick Nolthenius described his approach to planetarium education at Cabrillo College using a basic A3P planetarium system from the 1950s with minimal special effects. Despite equipment limitations, he creates engaging shows through personal interaction, walking around the planetarium and directly engaging students with questions. His presentations focus on colorful, visually striking images of the solar system, tailored to different age groups but primarily elementary school students. The shows typically begin with 5 minutes of stars and music to allow for dark adaptation, followed by demonstrations of celestial motion and then a tour of the solar system with carefully selected images that spark curiosity. Rick emphasized making astronomy relatable by connecting cosmic phenomena to students' experiences, such as comparing Venus's surface to Hawaii's lava fields or describing Mercury's shrinkage like a "raisin in the sun." He noted that while adults might expect more special effects, children respond well to this interactive approach.

Relevant Q&A

Rosemary: How much iteration have you done over the years to refine your presentation, and how do you make variations for different age groups? 

Rick: I primarily get elementary school groups but occasionally junior high or high school students. I update photos when new missions provide cool images, and I ask groups if there's something specific they want to see. My standard show is the solar system because it's relatable to non-specialists.

Rosemary: Do you do any photo editing to bring out colors more than what's straight off the image? 

Rick: Sometimes I use Photoshop to enhance colors, but I try not to go overboard. Most images are already processed by JPL, so I mainly size and crop them

Topic 2: Asteroid Occultation Research

Rick detailed his work studying asteroids through occultation observations, where asteroids briefly block the light from distant stars. This technique provides extremely precise measurements of asteroid size, shape, and position—often more accurate than what can be obtained with the world's largest telescopes. The methodology involves using specialized equipment including a video time inserter that timestamps video frames with GPS precision, allowing measurements down to 1/10,000th of a second. By combining observations from multiple locations along an occultation path, researchers can map asteroid outlines with remarkable precision. Rick described several significant occultation campaigns, including observations of the asteroid Phaethon (parent body of the Geminid meteor shower) and the Didymos/Dimorphos system that was the target of NASA's DART mission. These observations provide critical data for mission planning and help determine asteroid properties. The discovery of binary asteroids through occultations is particularly valuable as it allows for mass calculations using Kepler's Third Law, which when combined with size measurements yields density information that reveals composition.

Relevant Q&A

Jeff: Have you ever tried exoplanet transits? 

Rick: We did try one with a UCSC professor who came to Cabrillo because we had the right gear, but we got clouded out.

Jeff: How much does your occultation rig cost? 

Rick: Altogether about $2,500, but prices have increased. The telescope alone (Celestron 8SE) is now about $2,000. There's now a more efficient system called Astrid available for about $800 that includes the camera, recording gear, and GPS.

Topic 3: Recent Discoveries and NASA Mission Support

Rick shared several recent discoveries from his occultation work, including the confirmation of the first binary asteroid discovered through occultation (Arecibo) and the discovery of a new moon around the Kuiper Belt object Quaoar. The Arecibo observations revealed that the primary and secondary bodies have different densities (1.6 g/cc and 1.2 g/cc respectively), suggesting different compositions and formation histories. Rick also described high-value occultation observations supporting NASA missions, including precise positioning of Eurybates, a target of the Lucy mission to Jupiter's Trojan asteroids. Despite challenging weather conditions, Rick and his colleague Kirk Bender drove hundreds of miles to capture a successful occultation of Eurybates, providing critical data for mission planning. Most recently, Rick discovered a second moon around Quaoar, which is particularly interesting because Quaoar already has two rings that exist beyond the Roche limit where theory suggests rings shouldn't be stable. This discovery will be the subject of a forthcoming paper in the Astrophysical Journal Letters and represents an important contribution to understanding these distant objects.

Relevant Q&A

Rosemary: Of the people who work on occultations like you do, are many of them associated with small universities that have some observational astronomy aspect but don't have a large budget? 

Rick: Most do not have university access. If the star is brighter than 14th magnitude and conditions are favorable, small affordable telescopes can do the work. The real challenge isn't equipment but travel—most occultation paths are very narrow, requiring observers to drive to specific locations to capture data. Of Rick's 60-70 successful occultations per year, only 3-4 were observable from his home observatory.

Relevant Q&A

Jeff: Have you ever tried exoplanet transits? 

Rick: We did try one with a UCSC professor who came to Cabrillo because we had the right gear, but we got clouded out.

Jeff: How much does your occultation rig cost? 

Rick: Altogether about $2,500, but prices have increased. The telescope alone (Celestron 8SE) is now about $2,000. There's now a more efficient system called Astrid available for about $800 that includes the camera, recording gear, and GPS.

Supplemental Resources and Readings

• Exoplanet Watch program run out of Goddard Space Flight Center was mentioned as a citizen science opportunity similar to occultation work

• Astrid system was recommended as an efficient equipment package for occultation observations, costing about $800

• A forthcoming paper in the Astrophysical Journal Letters about the discovery of a new moon around Quaoar was mentioned.