Welcome to Houston Astronomical Society

“Kepler’s Laws”

By: Dan Roy

If you want to understand how anything orbits something else, you’ve got to know Kepler’s laws. After a short historical context Dan will describe how the impressive empirical work of Johanes Kepler built on the no less impressive work of Tycho Brahe to produce three laws that are still used today to compute the orbits of celestial bodies including that of our spacecrafts. Using the Galilean satellites of Jupiter, Dan will illustrate the elegant simplicity of Kepler’s laws. Only simple algebra is used and the logarithmic scale so often used in astronomy is gently introduced. A short bibliography is provided at the end for the nerds like Dan who love calculus.

To see the video, click Kepler's Laws.

“The ‘New Astrophotography’ and HAS”

By: Matt Boerlage & Erica Coenen

Astrophotography has changed dramatically over the past few years, and HAS members are responding! Innovations like phone app controls, harmonic drives, CMOS sensors, open-source processing software, and free YouTube guides have created a fresh energy—perhaps even a new era—in amateur astronomy. This exciting shift is drawing in a wave of new amateur astronomers, complementing traditional stargazing with creative and technical exploration, blending artistic passion with scientific curiosity.

Matt and Erica will share the story of how the AP SIG began at HAS and the growing community of astrophotographers it has inspired. Novice-friendly monthly webinars, in-person events, file-sharing opportunities, and exciting new areas to explore are all part of this movement.

You’re warmly invited to join this vibrant new chapter in amateur astronomy—you won’t want to miss it!

Speakers: Matt and Erica moved from The Netherlands to Houston about 10 years ago. Both hold PhDs in Mechanical Engineering from Eindhoven University of Technology and work in the Houston energy industry.

Their passion for astrophotography ignited two years ago, leading them to join the Houston Astronomical Society. They organize the astronomy outreach nights at the Kleb Woods Nature Preserve (Please join us Saturday, December 7th 5:30PM, either as participant or volunteer).

Matt and Erica’s interests include astrophotography and scientific imaging, with a focus on spectroscopy. Recently, Matt became a member of the AAVSO (American Association of Variable Star Observers). A year ago, Matt & Erica began hosting the monthly Astrophotography Special Interest Group webinars, every fourth Wednesday of the month.

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To see the video, click The ‘New Astrophotography’ and HAS.

All the fall objects are looking pretty good this month. Especially at the picnic & star party. Find details about both the visual and the astrophotography HAS Texas 45 observing programs under the Programs menu. Or here: https://www.astronomyhouston.org/programs. 

The Birth of Stars: Unraveling a Cosmic Conundrum

By: Peggy Mueller

It is now well accepted that stars form from clouds of gas and dust that collapse under their own gravity. However, if the angular momentum of the collapsing cloud was not removed during its formation, the young star would spin up so much that it would ultimately tear itself apart. Nevertheless, there are young stars rotating at a fraction of their break-up speed. How can we explain this conundrum? After an overview of the early stages of stellar evolution, this talk will focus on how we tested one of the explanations for this puzzling observation and what we learned.

Speaker Bio: Peggie Mueller has been a member of the Houston Astronomical Society since 2021. Her interest in astronomy deepened in 2016 after taking Modern Astronomy as part of the Master of Liberal Arts program at Rice University. Under the mentorship of Prof. Chris Johns-Krull, Peggie developed her capstone project which led to a published paper, Tests of Disk-Locking in T Tauri Stars of the ONC, in the March 2024 Astrophysical Journal. Tonight’s talk draws from their research, offering insights from her project and ongoing engagement in astronomy.

To see the video, click The Birth of Stars: Unraveling a Cosmic Conundrum.

“Open Clusters and Asterisms”

By:  Larry Mitchell

Visually stellar open clusters and asterisms are unique as no two clusters are alike, and often stunning detail can be seen.  This differs from observing many deep-sky objects which due to distances and physical parameters often present similar apparent views.  We will explore how star clusters form, where and what they are, and how they evolved to their present state.  Unpublished data will be presented which displays a level of accuracy previously un-imagined. Stellar clusters are particularly valuable for stellar evolution analysis, and this also applies for objects in other galaxies, which are visible in amateur instruments, and we will explore some of these. It is always great to visually observe this wonderful universe through any telescope, but it is much – much better if one knows something about the object being seen. We will analyze and view some of the finest stellar clusters in the current fall and winter sky

Our Speaker: Larry Mitchell has had a lifelong interest in astronomy, He began observing at age 10 with a 3-inch telescope and in 1985 became a serious visual astronomer – Still Serious 40 years later! Larry owns too many telescopes including a  36-inch f/5 which he recently sold, a 30-inch f/3.3, a 20-inch f/5, an 18-inch f/4 as well as several others.

• Discovered supernova SN1994S, a type 1a supernova.
• Discovered and cataloged 117,300 galaxies and the author of “Mitchell’s Anonymous Catalog”, the “MAC” - Found in MegaStar
• Observed and cataloged all 2500+ of Wiliam Herschel’s nebulae and star cluster discoveries.
• He has a book currently being published by the American Astronomical Society (AAS) on visual observing describing technical info and how to find obscure objects, which may be viewed in medium sized aperture telescopes - Without Using a Computer.
• Larry has written several visual astronomy articles in various magazines
• Is the recipient of the Texas Star Party “Lone Stargazers” award and the “Omega Centauri” award and has an asteroid named after him - Asteroid – “126183 Larrymitchell”
• Since 2000, Larry has been the chairman of the Texas Star Party “Advanced Observing Program” and has been Co-Chairman of the Stellafane Observing Olympics for the past 8-years.
• Larry loves traveling the world giving lectures and observing the night sky, and is always ready to view this magnificent universe and share the adventure with his many astronomy friends ___________________________________________________________________________________

To see the video, click Open Clusters and Asterisms.