Orange County Astronomers

First Quarter Moon
2021-02-19, 2021-01-20, 2020-12-21
Views: 2

Open Spiral Bar
2021-02-13 22:00 - 23:30, 2021-01-09 22:00 - 23:30, 2020-12-12 22:00 - 23:30 (America/Los_Angeles) | Online
This event is free and open to public, to attend please register using the zoom.us link on the box above.
Come and socialize with your fellow astronomy enthusiasts face-to-face virtually!
Bring your latest astrophotos, mini-presentation, questions or none and your own refreshments.

Views: 2

New Moon
2021-02-11, 2021-01-12, 2020-12-14

Online Beginner's Class
2021-02-05 19:30 - 21:30 | Online
RSVP using the zoom.us link on the box above.
Please install/update zoom client prior to the event.
This is the “How to Use Your Telescope” session of the Beginners Astronomy Class. If you have a telescope and would like some help learning to set it up and use it, attend this on-line class.
For details, please visit here.
Free and open to the public as well as members of OCA.
Views: 2

Last Quarter Moon
2021-02-04, 2021-01-06, 2020-12-07

Full Moon
2021-01-28
The first full moon of the year is colloquially known as Wolf Moon in many northern cultures. A Full Moon occurs when the Sun and the Moon are on opposite sides of the Earth.
Views: 2

Online Ventura County Astronomical Society's General Meeting
2021-01-15 20:30 - 22:00 | Online
This is an online event held by OCA for VCAS.
No prior registration is required but when entering the webinar, zoom will ask for your name and email.
At the time of the meeting, to attend via zoom app click here, via your browser click here.
To install the zoom app click here.

Views: 2

Online General Meeting - January 2021
2021-01-08 19:30 - 21:30 | Online
This is an online event, to attend please register with zoom using the link on the box above.
Dark Matter and the Dance of Dwarf Galaxies

Major galaxies, such as our cosmic home the Milky Way, the nearby Andromeda galaxy, or Centaurus A, are surrounded by swarms of smaller dwarf satellite galaxies. Over the past 15 years, our knowledge of these satellite galaxies has exploded. The number of known Milky Way satellites has quadrupled, and highly precise measurements of their motions have provided unprecedented insights into their complex orbital dance. In my research, I investigate the distribution and motion of satellite galaxies to test our ideas of how the cosmos in general, and galaxies in particular, have formed and evolved. Our current leading model of cosmology was largely developed on cosmic scales, and implies that most of the mass in the Universe is dominated by unknown stuff: Dark Matter. Based on this cosmological model, computer simulations can nowadays follow the emergence and evolution of structure in model universes. These simulations predict the distribution and properties of galaxies down to the smallest scales (astronomically speaking). They predict a highly chaotic tangle of satellite galaxies. In contrast, my research finds that the observed situation resembles an ordered choreography: the satellite galaxies around the Milky Way, Andromeda, and Centaurus A are aligned along planes. Many satellites also move along these structures in a common direction. This finding poses a serious challenge to our model of cosmology – and might point at a fundamental misinterpretation of cosmic proportions.
Marcel S. Pawlowski

My research is situated at the intersection of observations and cosmological simulations. I am most interested in testing our cosmological knowledge and our understanding of the properties and dynamics of dwarf galaxies with observations of nearby systems of satellite galaxies. After receiving my PhD from the University of Bonn in 2013, I moved to the United States for a postdoc position at Case Western Reserve University in Cleveland, Ohio. In 2016, I was awarded a NASA Hubble Fellowship to work at the University of California Irvine. At the end of 2018 I moved back to Germany to my current position as Schwarzschild Fellow at the Leibniz-Institute for Astrophysics in Potsdam.
Views: 2

Earth's Perihelion
2021-01-02 05:30 - 05:40
At 5:30am, the Earth will reach its perihelion—the point on its orbit that is closest to the Sun.
Views: 2

Quadrantids Meteor Shower
2021-01-02 - 2021-01-03
The Quadrantids is an above average shower, with up to 40 meteors per hour at its peak. It is thought to be produced by dust grains left behind by an extinct comet known as 2003 EH1, which was discovered in 2003
Views: 2

Online Beginner's Class
2021-01-01 19:30 - 21:30 | Online
This event is free and open to public; to attend please register using the zoom.us link on the box above.
This session of the Beginners Astronomy Class covers the science behind the telescope.
How do our eyes actually perceive objects we see in the telescope and what is the physics that allows that perception.
For details, please visit here and download the sample information PDF package.
Views: 2

2020 Blair Award Ceremony
2020-12-30 19:00 - 19:30
Topic: WAA G. Bruce Blair Award
Time: Dec 30, 2020 07:00 PM Pacific Time (US and Canada)
Join Zoom Meeting
https://us02web.zoom.us/j/84876958189?pwd=[REDACTED]

An astronomy enthusiast since childhood, Bing F. Quock joined Morrison Planetarium’s staff in 1973 and joined the Planetarium Lecturer team in 1975, presenting live shows using the classic Academy-made star projector. In the late ’70s, he taught several semesters of Introductory Astronomy at one of City College of San Francisco’s satellite campuses under Don Warren, then the head of CCSF’s Astronomy Department. From 1982-2003, he served as Morrison Planetarium’s Assistant Chairman and Show Producer, writing and producing approximately 110 planetarium shows for the public, school, and special event audiences during that time, as well as teaching informal astronomy classes and guiding observing sessions for Academy members and youth. During this period, he wrote the “Skywatcher’s Guide” that appeared regularly in the Academy’s quarterly magazine and which continues today, still authored by him, in digital form on the museum’s website (www.calacademy.org). He also created the Academy’s popular “Pocket Almanac,” and since the ’80s has written daily skywatching snippets under the Planetarium’s byline for syndication to about 30 newspapers around the country. He has been a frequent interviewee on Bay Area radio and television, explaining eclipses, meteor showers, and other astronomical phenomena.

From the mid-1990s to 2017, he assisted Ron Dammann as one of the principal operators of the Hume Observatory at Pepperwood Preserve in Sonoma, educating and entertaining small groups of visitors with views of the night sky through the facility’s instruments, which included a 6.4″ Alvan Clark refractor once owned by George Davidson and “Edelweiss,” a 17″ Dobsonian reflector donated by Doug Berger. Although the observatory and its equipment did not survive the Tubbs wildfire of 2017, Bing continues guiding occasional skywatching sessions as part of Pepperwood Preserve’s educational program.

From 2004-2006, he served as Acting Director of Morrison Planetarium when the Academy of Sciences temporarily relocated to downtown San Francisco, while the Academy buildings were renovated. He performed astronomy outreach to schools with an inflatable planetarium until
the new Academy reopened in the Park. Since 2007, he has held the position of Morrison Planetarium’s Assistant Chairman and presently continues concentrating on outreach, partnerships, and astronomy communication to the media.
Views: 2

Full Moon
2020-12-29, 2020-11-30

First "Christmas Star" in 800 years
2020-12-21 17:00 - 17:15
This December 21st, on the winter solstice, Jupiter and Saturn will be their “closest” in 800 years. Not since the Middle Ages has this close encounter between these two planets occurred. The event will occur 45 minutes after sunset in the southwest and will result in a spectacular view! Get out your cameras!!
Views: 2

Ursids Meteor Shower
2020-12-21 - 2020-12-22
Catch the shooting stars of the last major meteor shower of the year, the Ursids, when it peaks between the night of December 21 and 22, 2020.
Views: 2

Winter Solstice
2020-12-21

Online Solar Eclipse
2020-12-14 06:30 - 21:30 | Online
The last solar eclipse of 2020 will be on Monday December 14th and is going to be only visible from Southern America.
Behold that OCA in collaboration with Prof. Elizabeth Villanueva and her students from Colegio Alberto Pérez has arranged for an international live broadcast of the event.
The program will be held from the start of the eclipse at 6:30am PST up until its end at 9:30am PST. In addition to the Chilean view of the sun, there will be short presentations by students and teacher from all around the world.
To attend, have zoom installed and then visit the page below at the appropriate time.
https://www.astrozoom.space/attend

Views: 2

Geminid Meteor Shower
2020-12-13

Online General Meeting - December 2020
2020-12-11 19:30 - 21:30 | Online
This is an online event, to attend please register with zoom using the link on the box above.
State of the Universe Report

This lecture will discuss the current understanding and the latest discoveries regarding cosmology—the science of the universe as a whole—and galaxies and planets. There is overwhelming evidence that most of the density of the universe is invisible dark matter and dark energy, with atomic matter making up only about five percent of cosmic density. UC Santa Cruz cosmologists helped to create the standard modern cosmological theory—but the latest high-precision measurements have revealed potential discrepancies that may require new physics. Galaxies were long thought to start as disks of gas and stars, but observations by Hubble Space Telescope show that most galaxies instead start pickle-shaped. More massive galaxies have massive black holes at their centers, and matter falling onto these black holes causes outflows of energy that can strongly affect their host galaxies. Information about planetary systems is growing rapidly with new observations, and our own solar system seems increasingly to be unusual.
Joel R. Primack

Joel R. Primack specializes in the formation and evolution of galaxies and the nature of the dark matter that makes up most of the matter in the universe. After helping to create what is now called the “Standard Model” of particle physics, Primack began working in cosmology in the late 1970s, and he became a leader in the new field of particle astrophysics. His 1982 paper with Heinz Pagels was the first to propose that a natural candidate for the dark matter is the lightest supersymmetric particle. He is one of the principal originators and developers of the theory of Cold Dark Matter, which has become the basis for the standard modern picture of structure formation in the universe. With support from the National Science Foundation, NASA, and the Department of Energy, he has been using supercomputers to simulate and visualize the evolution of the universe and the formation of galaxies under various assumptions.
Here’s the link to a recording of my 10 November 2020 UCSC Emeriti Research Lecture “State of the Universe Report: Cosmos, Galaxies, Planets” on YouTube:
https://www.youtube.com/watch?v=BAuiSC0iUXE

Here are some of my recent research results that may be of wider interest:

— Local measurements of the the Hubble parameter give H_0 = 73 ± 1 km/s/Mpc, while measurements of the Cosmic Microwave Background extrapolated to the present with the standard ΛCDM cosmology give H_0 = 67 ± 0.5 km/s/Mpc. This “Hubble tension” could be resolved if there was a brief period when dark energy contributed about 10% to the cosmic density about 35,000 years after the Big Bang. I initiated the first N-body simulations with this Early Dark Energy (EDE) cosmology. Our paper on this https://arxiv.org/pdf/2006.14910.pdf was led by Anatoly Klypin. We found that EDE predicts 50% more rich clusters of galaxies at redshift z=1 than standard ΛCDM, and many more galaxies at higher redshifts. These predictions will be tested by new astronomical surveys now underway. We are resubmitting the paper to MNRAS in response to a favorable referee report, so it will be published soon. We are setting up to run 500 Mpc/h paired simulations with Bolshoi resolution of standard ΛCDM and EDE; the use of the same random number seed will ensure that all the large-scale structures will correspond in these simulations. We plan to do abundance matching with both simulations, to fill all the halos with UniverseMachine and Santa Cruz SAM galaxies, and to compare with observations.

— I initiated a paper that shows that Earth may be a “Goldilocks” planet in a new way, with enough radioactive heat generation to power plate tectonics and not too much to kill the geodynamo generating the Earth’s magnetic field. Tectonics and a magnetic field may both be necessary for the evolution of complex life. Earth’s radioactive heat is generated by the two longest-lived radioactive elements thorium and uranium, which are produced in extremely rare events such as neutron-star mergers — as a result, the amount of Th and U varies a lot between different planetary systems. Our paper, led by my UCSC colleague Francis Nimmo, was published November 10
https://ui.adsabs.harvard.edu/abs/2020ApJ…903L..37N
The UCSC press release is at https://news.ucsc.edu/2020/11/planet-dynamos.html ,
with some popular articles at
https://astrobiology.nasa.gov/news/how-radioactivite-elements-may-make-planets-suitable-or-hostile-to-life/
https://www.scientificamerican.com/article/stellar-smashups-may-fuel-planetary-habitability-study-suggests/
https://cosmoquest.org/x/2020/11/radioactive-elements-may-be-crucial-to-rocky-planets-habitability/
https://www.centauri-dreams.org/2020/11/13/radioactive-elements-and-planetary-habitability/
https://astrobites.org/2020/11/17/radiogenic-heat-hurts-dynamos/
https://www.universetoday.com/148796/what-role-do-radioactive-elements-play-in-a-planets-habitability/

— I’ve continued to make novel uses of machine learning to compare simulations with observations and to analyze observations. My group’s latest papers on this focused on giant clumps found in HST images of most redshift z > 1 star-forming galaxies. In https://ui.adsabs.harvard.edu/abs/2020MNRAS.499..814H we trained a CNN to measure the masses of giant clumps; we made public our analysis of the entire CANDELS galaxy dataset, and we used a complete set from GOODS-N and S with 7 wavebands to measure clump properties as functions of galaxy properties including sSFR, radius, and stellar mass. In https://ui.adsabs.harvard.edu/abs/2020arXiv201106616G we trained a CNN to measure the lifetimes of the clumps in the CANDELS data; this paper was just accepted for publication. Our earlier paper that made extensive use of machine learning to compare HST observations with theory was profiled in https://news.ucsc.edu/2018/04/deep-learning-galaxies.html

Views: 2

Ursid Meteors
2020-12-06 08:00 - 17:00

Online Beginner's Class
2020-12-04 19:30 - 21:30 | Online
This event is free and open to public; to attend please register using the zoom.us link on the box above.
The 6th session of the Beginners Astronomy Class covers the basics of astrophotography, covering different types of imaging, how different types of cameras are used for this kind of photography, and other equipment and considerations for taking a good picture.
This session is taught by Kyle Coker, who is active in the club’s AstroImaging special interest group.
Free and open to the public as well as members of OCA.
Views: 2
