Author: vern@raben.com

Topic

“Ancient Moonwatchers” by Dr. Erica Ellingson with the Department of Astrophysical and Planetary Sciences at the University of Colorado, Boulder.

Abstract

While the monthly and yearly cycles of the moon are familiar to most modern skywatchers, the longer and more subtle “lunar standstill” cycles are more difficult to track. Ancient skywatchers from around the world may have noted the shifting positions of the moon, but the evidence is sometimes unclear.  In this talk, I’ll model how the precession of the Moon’s orbit causes small changes in the observed positions or moonrise and moonset over its 18.6 year period, and review astronomical and archaeological evidence from several sites from around the world that have been claimed as lunar standstill observatories. The most convincing is actually in SW Colorado, at Chimney Rock National Monument, and I’ll describe our activities during the current major lunar standstill season, including  moonrise events in September 2025.

Picture of the Moon at Lunar Standstill at the Chimney Rock National Monument (https://www.chimneyrockco.org/) near the Four Corners area of Colorado.

Bio

Prof. Erica Ellingson, 

Department of Astrophysical and Planetary Sciences, 

University of Colorado Boulder

Dr. Ellingson is an astrophysicist who delights in using telescopes large and small, in space and at observatories around the world. Her work includes investigating galaxy clusters, the evolution of galaxies, black holes, and the mysterious cosmological forces of dark matter and dark energy. 

Her research also includes historical and archaeo-astronomy and she is an editor with the international Journal of Skyscape Archaeology. She also teaches and produces educational programs at the Fiske Planetarium at the University of Colorado and is an astronomical consultant with the US National Park Service. 

Location

The meeting will be at the First Evangelical Lutheran Church, 803 Third Avenue, Longmont, CO 80501.

Topic

“Impact experiments at NASA’s Ames Vertical Gun Range” by Dr Dan Durda, SWrI

Abstract

The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) sample return mission to the near-Earth asteroid (NEA) (101955) Bennu and the Hayabusa2 mission to (162173) Ryugu offer unprecedented opportunities to gain fundamental new knowledge about the processes governing regolith formation and redistribution on small bodies.  Both asteroids display unexpected examples of small crater and boulder morphologies that raise new questions about the properties of coarse regoliths on small, primitive NEAs and processes governing the evolution of their surfaces. Experimentally documenting the range in morphology of fracture patterns of boulders in coarse regoliths and the form of small craters in coarse regoliths as a function of parameters like impact energy, depth of burial, and mechanical strength is a crucial step in the process of relating these amazing spacecraft images to the actual physical properties of these asteroids surfaces. I will share some of my results from my impact experiments at NASA’s Ames Vertical Gun Range.

Bio

Dr. Dan Durda is a principal scientist in the Department of Space Studies at Southwest Research Institute (SwRI) in Boulder, Colorado. He has more than 20 years’ experience researching the collisional and dynamical evolution of main-belt and near-Earth asteroids, Vulcanoids, Kuiper belt comets, and interplanetary dust. Dr. Durda is one of three SwRI payload specialists who fly on multiple spaceflights on commercial reusable suborbital vehicles.

Location

The meeting will be at the First Evangelical Lutheran Church, 803 Third Avenue, Longmont, CO 80501.

The next Longmont Astronomical Society’s club meeting will be on Thursday, April 24, 2025, starting at 7:00 pm. No speaker is scheduled so we’ll have open forum member presentations. LAS members are invited to give a 5 to 10 minute presentation on an astronomy related topic. 

Tell everyone about:

• An observing or imaging project that you are doing
• Good things and bad things about some equipment you have purchased
• Talk about an image you have taken – what is in it, equipment used, how you processed it
• Interesting techniques you have learned about
• Just about anything astronomy related that interests you will probably interest others as well

You may present in-person or via Zoom. Not mandatory but it would be helpful if you email Vern that you are interested in presenting and the topic before the meeting.

The meeting will be at the First Evangelical Lutheran Church, 803 Third Avenue, Longmont, CO 80501. If you cannot attend the in-person meeting, it will be available on Zoom. Video of the meeting will be available on the LAS member portal website https://members.longmontastro.org on Friday after the presentation.

Dr. Marc Buie, SWRI in Boulder will give a presentation about the Lucy Mission. The Lucy mission is a NASA space probe launched on October 16, 2021, designed to explore a group of asteroids known as the Trojan asteroids, which share Jupiter’s orbit around the Sun. Over its planned 12-year mission, Lucy will conduct flybys of several asteroids to gather data about the early solar system and the formation of planets.

Marc William Buie is an American astronomer and prolific discoverer of minor planets who works at the Southwest Research Institute in Boulder, Colorado in the Space Science Department.[ Formerly he worked at the Lowell Observatory in Flagstaff, Arizona, and was the Sentinel Space Telescope Mission Scientist for the B612 Foundation, which is dedicated to protecting Earth from asteroid impact events.

The meeting will be at the First Evangelical Lutheran Church, 803 Third Avenue, Longmont, CO 80501. If you cannot attend the in-person meeting, it will be available on Zoom. Marc will present in person. Video of the meeting will be available on the LAS member portal website https://members.longmontastro.org a couple days after the presentation

The next Longmont Astronomical Society’s club meeting will be on Thursday, February 20, 2025, starting at 7:00 pm.

Longtime LAS member, Mike Hotka, will give a presentation about a recent Astronomical League Observing Program he just completed.

Mike will talk about some of the activities he performed while completing the Astronomy Before The Telescope Observing Program. More information about what is behind this talk can be found on the League’s website at: https://www.astroleague.org/astronomy-before-the-telescope-observing-certificate/

Details of the Zoom connection for this meeting will be forthcoming.

Hope to see everyone there.