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.

nova new
See some carbon stars!

Rich Combs's short list 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
Talk follows

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

September's meeting

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 membership page.

Upcoming star parties

We have planned the following star parties: Please contact 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 through 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 Cafepress 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.