CBA Concord

Long. 122W Lat +38
Lew Cook operates CBA Concord from the San Francisco suburb of Concord, approximately 30 miles (50 km) East of the City. One of the 2 telescopes formerly at CBA Concord is now back at Concord from Pahala, Hawaii at CBA Pahala The operating telescope is a 73 cm reflector operated at prime focus on an English cradle mount. It uses an STL 1001E, STF 8300M or STXL 6303E camera for collection of CCD images. These are reduced using AAVSO's VPhot, Richard Berry and Jim Burnell's AIP4WIN or Pierre de Pontierre's Lesve Photometry .

Lew's CCD Camera Project
Contains some collected CBA light curves.
The web page linked on the left panel describes the construction of the original Cookbook camera and re-work of the 44 cm telescope.The 44 cm telescope is back in Concord.

The re-build of the second (73 cm) telescope on an English style cradle mount, modified for steel lattice structure and scaled up from the 50 cm reflector of E. C. Silva, shown on Pedro Re's web pages, was completed. It operates at prime focus. Construction began in the fall of 1999 and the telescope was finally put into routine operation in the spring of 2003.

Despite being near sea level, in a suburban location, and near famous foggy San Francisco, Concord provides abundant clear skies for astronomy, especially in the summer and fall. Climatically, Concord is considerably different from San Francisco, being on the eastern side of the Berkeley Hills which stop much of the fog from reaching inland. To the south about 50 miles (80 km) is the Lick Observatory of the University of California.

A example of data collected for the CBA effort on V603 Aquilae is presented below.

One of the first stars observed using the CCD camera was V603 Aql.

V603 light variation on July 18, 1999 and July 1, 2003.
When this star was observed again in 2003, periodic humps were found at a period of 0.1454 day (3.48 hours). The data from 70 hours of observation on 11 consecutive nights (June 21-July 1, 2003) was averaged over this period giving the following "Superhump" profile. The data is repeated over 2 cycles for clarity.

Lew's Home Page-

CBA Home Page

Just for fun - Lew's 1998 Solar Eclipse Pix
CBA Concord on the Clear Sky Chart
and two other sites where I get images
The Clear Sky Clock is generated by the Canadian Meteorological Center and owes its existence to Allan Rahill and Attilla Danko

Lew's Home Page
Lew's closed Hawaiian site - CBA Pahala where the 17 inch Newtonian resided until late 2014. It was shipped back to the mainland where it has been reconfigured to a prime focus camera for 2018. It is housed in a clamshell building located in the wind shadow of our house and will be used for photometry. The neighbor's tall redwood trees to the southeast obstruct the sky.
Please contact me about my work for CBA if you have questions.

This page was last updated on March 25, 2018