Welcome to the Tri-Valley Stargazers Astronomy Club's web site. There is a lot
of information here on the many activities of the Tri-Valley Stargazers
(TVS). Learn why you should join the club to get the most out of your
amateur astronomy hobby in the east San Francisco Bay Area.
The Latest News & Upcoming Events
A scenario of late supernova injection into the protoplanetary disk is consistent with formation of our Solar System
in an active star-forming region of the galaxy. Slight differences between the non-radiogenic isotope compositions of
the first solids in the Solar System (calcium-aluminum-rich inclusions, or CAIs) and terrestrial rocks are
pervasive. Dr. Brennecka's work shows that the isotopic compositions of elements spanning a large mass range in CAIs, are
uniform, and yet distinct from the average Solar System composition. Relative to younger objects in the Solar System,
CAIs contain positive r-process anomalies in isotopes A < 140 and negative r-process anomalies in isotopes A >
140. This fundamental difference in the isotopic character of CAIs around mass 140 necessitates (i) the existence of
multiple sources for r-process nucleosynthesis and (ii) the injection of supernova material into a reservoir untapped
by CAIs. These distinct nucleosynthetic differences between CAIs and terrestrial rocks provide the isotopic character
of the last significant supernova to input material into the Solar System. Further details of this work can be found
Dr. Gregory Brennecka received a PhD from Arizona State University in Isotope Geochemisty in 2011 with a thesis
focused on documenting and understanding the natural variation in uranium isotopes in terrestrial and meteoritic
samples. Much of his academic research and interest is now dedicated to determining isotopic characteristics of the
first solids to form in the Solar System and what these characteristics can tell us about Solar System formation and
early evolution. Dr. Brennecka is particularly interested in understanding short-lived radioisotopes and the role
that supernova input had on the protostellar nebula and the early protostellar disk.
H2O Open House
Our next open house is scheduled for Friday May 23 at the club's dark sky site,
Hidden Hill Observatory
aka H2O. The Friday date coincides with a potential new meteor shower that is expected to result
from debris from Comet 209P/LINEAR (see p.30 of the May issue of S&T). This comet is making an extremely close pass
by Earth on May 26 and it is possible that a meteor storm could result as Earth passes through debris
from its tail.
Anyone can come to our open houses, not just club members; but you cannot go there without an escort. We
will meet at the corner of Mines and Tesla Roads at 6:30 PM, then caravan to the site on a drive that takes
about 50 minutes. The admission is $3/car; please bring the exact amount. There is no gas on the
way, so be sure to gas up before leaving. The site is essentially in the
wilderness, so there is no electricity and water, and there are only a couple of pit toilets. Cell-phone reception is
iffy at best. While there is a picnic table there, you really should bring your own chair. If you need a flashlight,
bring a red LED flashlight, not a white-light flashlight. And use masking tape over your car door and interior
lights, or pull the fuse. If you don't have a scope, you can always find someone who is
willing to let you look through theirs. And don't forget to bring your binoculars. Expect to stay until about
midnight and get back to Livermore at around 1:00 AM.
Another open house is planned for Saturday, August 16.
Gert Gottschalk took some nice
at our last open house.
Yosemite Star Party
David Feindel will be coordinating this year’s TVS star party at Glacier Point, Yosemite National Park. We were lucky
in drawing the new Moon weekend of June 27-28. Tri-Valley members who bring telescopes for public observing will
receive free camping at the Bridalveil campgrounds. On these dates sunset occurs at about 8:35pm with sunrise at
about 5:50am. Contact
for more information.
TVS has back issues of S&T and Astronomy magazines freely available. If you are interested in being a recipient of
these valuable resources of astronomical history, please make your interest known at a forthcoming club meeting. First come,
TVS Logo Wear
You may have seen some TVS members wearing shirts and jackets
embroidered with the TVS logo. If you are interested in obtaining an
embroidered logo item, you can do so by ordering whatever you would like
Land's End's Corporate Sales
section and specifying TVS logo #0118948. You will need to set up an account, which will
ask for the logo number and the TVS customer number (3452021).
TVS has also set up shop at
for members to buy non-embroidered TVS logo wear. You can have the TVS
logo put on t-shirts, mugs, buttons, hats, coasters, etc. You buy
through Cafepress, and Cafepress sends TVS a portion of the proceeds.
Visit the web site to see all the TVS logo possibilities.