Orange County Astronomers

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Orange County Astronomers (OCA) started life in 1967 when a small group of intrepid amateur astronomers got together to form a club. Those were the days when an amateur built his own telescope, usually a Newtonian reflector. It was a laborious process of grinding a mirror to as close to a 1/4 wave as you could get. Then you built the tube and assembly so you could actually search out a dark patch of sky to look up at the stars. It helped to know about stepping motors and who was building the best drives to keep your telescope tracking your object. And that was another thing – you had to get on intimate terms with the night skies for all seasons. That was a daunting task for many and proved to be a barrier to many but the most dedicated observer.

Panoramic view of an OCA General Meeting.


Computers were just coming onto the personal scene. The operating systems were mostly proprietary to the computer maker. That meant that Kaypro had its own system; so did many of the other small manufacturers. A big system at that time might be 124 KB. Yes, I said KB, as in kilobytes. It was nirvana indeed when the first system came out that was a whole MB. The game changer was the standardization by IBM of the personal computer and the Operating system by Microsoft. Apple was also on the scene then, but chose to keep their Operating system a proprietary one. There were no CCD cameras for amateurs and no GoTo systems, like there is now. So people in those days hung out with the engineers in the club who were doing most of the experimentation with the then esoteric stuff like the CCD chips and nitrogen-cooled cameras.

It was about this time that Tom Johnson started work on a Schmidt-Cassegrain design for small telescopes. While the design had been around since the 1930s, only a few of the instruments had been produced. The problem was the difficulty in figuring the corrector plate. By the mid 1960s Tom had built his first Schmidt-Cassegrain, an 18 inch model. He realized that he would have to build smaller telescopes to appeal price-wise to the growing amateur community. The first models were still too high for the typical amateur astronomer, but as prices came down, more amateurs could afford them.

So the Orange County Astronomers started and grew at the right time to take advantage of this coming era. And as the OCA grew, the club ultimately moved into its present meeting place at Chapman University. Speakers at the club meetings also began to reflect the growing size of the OCA community; members were hearing professional astronomers showcase their research.

Dark Sky Observing Facility[edit]

In the 1970s the OCA began to develop some land they had traded for into the present Anza Observatory site, complete with the 22 inch Kuhn Telescope, named for its designer and builder, William Kuhn. Anza started as a site with amateur pads; the Kuhn and its Observatory officially opened in September 1984. Today there are several different areas on the site for observing pads, as well as several small observatory sites for individual members. The club holds a star party there every month, during which a certified telescope operator guides the big telescope around the sky for all to see the view from a fine instrument. Trained members called star members operate the telescope. The site also has a warming area – a mobile home that has a kitchen and bathroom, and a place to defrost in the winter, or cool off in the summer heat. Blackstar Canyon is the other club site for a monthly star party for those who want to stay closer to home.


OCA has a cornucopia of activities for those interested in delving deeper into Astronomy, astronomy software, astroimaging, and astrophysics. These are the SIGs, or special Interest Groups, that meet monthly, except for the GoTo group, which is bi-monthly. They range from Beginners’ telescope classes, to Astroimaging, Astrophysics, Electric-Oriented Astronomers, GoTo and Outreach.


The outreach program is an informal group of members who take their telescopes to schools, libraries, and other public venues to share the wonderful experience of star gazing with children and adults alike. Last year the outreach program made 78 appearances.


OCA has an extensive library of video, DVDs and books that members can sign out. There are several courses there from the Teaching Company, including Alex Filippenko’s award winning DVD Astronomy course.

Telescope Loaner Program[edit]

A telescope loaning program is also ongoing, for those members who either have not purchased a telescope and want to “test drive” a type before putting down their hard-earned money, or for the new member just getting started in the hobby. And of course, the other members are always ready to extend a helping hand.

External links[edit]