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.
See some carbon stars!
will help you see some interesting carbon stars.
Next Public Meeting
Speaker: Jeff Baldwin
Mirror-Making Machine, SIT Testing, and Shop Strategies
Friday, September1 18, 2015
Doors open at 7:00 p.m.
Show & Tell starts at 7:30 pm
Unitarian Universalist Church
1893 N. Vasco Rd., Livermore
Next Board Meeting
Monday, September 21, 2015, 7:30 p.m.
Round Table Pizza
1024 E. Stanley Blvd, Livermore
Members are always welcome at board meetings. Pizza is optional.
The Latest News & Upcoming Events
Jeff Baldwin is a mirror maker in Lathrop, just south of Stockton. He has made
approximately 400 mirrors. Recently he and a friend made a mirror-making
machine that will produce mirrors up to about 46" in diameter. He is also using the
Slit Image Test (SIT) to produce high-precision mirrors of any diameter, any conic
constant, and any focal ratio. The machine is programmable to do many styles of
strokes and fixed-post grinding and polishing. In the future it will also have curve-generating
abilities. This machine has helped Jeff work mirrors that are too heavy
and large to physically manipulate.
The SIT was "invented" by Bill Thomas of Grass Valley, CA. It is a combination of
Hartman, Caustic, and other tests. The test allows the user to have high-precision,
works for large or small mirrors, fast or slow focal ratios, in stable rooms or in
unstable rooms, and can be done very quickly. Its repeatability is outstanding. Even
though it is a good idea to use other tests along with the SIT to finalize a mirror,
the test enables the optician to process mirrors very quickly and accurately. The
machine, the SIT, and shop systems all work together to make large aperture fast
focal ratio parabolic telescope mirrors of high quality. Shop systems and strategies
keep the optician working quickly, accurately, and safely.
The Jack Marling scope is back in operation at H2O!
The Jack Marling 17.5-inch telescope is back up and running
at H2O. Chuck and Roland reinstalled it on May 6, and
it went back into service for the first time at the H2O Open
House on May 9. The mount's motor is now working, and it was
put to good use on September 8th when a group of us were looking for
Pluto. It was nice to have a scope that tracked Pluto without
our needing to constantly make adjustments. Now that the scope
is in operation, you might want to consider becoming a patron
member so you can use it. For more information, visit our
Upcoming star parties
We have planned the following star parties:
- Friday, October 2, Alviso Adobe Park in Pleasanton for a Recreational Activities for the Developmentally Disabled (RADD) Star Party
- Saturday, October 17, Tesla Winery Star Party, 6:00-12:00
- Friday, October 23, Valley Christian School in Dublin
for further information.
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.