In 1954 Dr. R. E. Heckman with the help of Cpt. Jackson, Jim Johnston, Byron Painter, John Searle, and Newel White formed the Rapid City Astronomical Society (RCAS). On September 27th, 1978, the RCAS incorporated and changed its name to the Black Hills Astronomical Society (BHAS).

     The Hidden Valley Observatory had its beginning in the fall of 1963.  A decision was made to construct a permanently mounted telescope of sufficient size and performance to promote astronomy in Rapid City as well as encourage society members to further their own interests.  After investigating several sites, the present location (4715 Hidden Valley Road) was obtained on a twenty-five year lease from St. Martin's Academy, with subsequent 10-year renewals. With the exception of the dome, which was constructed by the Rapid City firm Rapid Tank, the entire project was constructed by RCAS members.  Financial support was given by the membership as well as interested businessmen in the form of both money and building materials.

     The observatory opened its doors to the general public in September, 1965, having its first "Journey to the Stars".  The opening was very well received as approximately 1,000 guests attended the first three nights of observing.  "Journey to the Stars" became an annual event where numerous other telescopes were setup outside for use by the public. Journey to the Stars has since been expanded to several nights each month from June through August.

     The Hidden Valley Observatory project was described in a feature article in the February, 1967 issue of Sky and Telescope magazine.

     Operation of the observatory was short-lived; however, for in the summer of 1967 vandals broke in and destroyed the optics of the telescope in addition to stealing many valuable items from the building.  About one year later, the RCAS, under new young leadership, decided to rebuild.  They raised money by various means and successfully paid off the old debts as well as making the renovations.

     The original telescope was a 12.5-inch (31.75 cm) Dall-Kirkham reflector.  Because of the amount of time and money involved it was decided to replace the telescope with a Newtonian reflector of the same size.  This change required the construction of a new observing platform and a longer tube for the new optics, which were purchased from Optical Craftsmen, Inc.  Space limitations inside the dome restricted the telescope to an f/5.89 focal ratio.  The addition of a large secondary diagonal resulted in the telescope having a wide bright field ideal for the observing and photography of deep-sky objects.  Deep-sky objects are relatively independent of the poor seeing conditions prevalent in our area. 

     Fine planetary detail can also be seen when atmospheric conditions permit.  The performance of the telescope has been enhanced by the addition of a fine set of 1.25-inch Brandon orthoscopic oculars and Barlow, color filters, a moon filter, a light pollution/nebula filter, a piggy back camera mount, a Telrad finder, a Solar-Skreen sun filter and a 2-inch low profile non-rotating helical focuser.

     The Newtonian telescope was carried on the original German type equatorial mounting.  It was equipped with a synchronous Right Ascension clock drive as well as a push button slow motion control for both axes.  Setting circles were provided for the location of objects from their celestial coordinates.

     In 2017 the 12.5-inch Newtonian was replaced by a 12-inch Meade LX200-ACF telescope mounted on the existing pier for operation in equatorial mode.

     All BHAS members in good standing have access to the Hidden Valley Observatory as part of their membership privileges.  However, in order to have individual key privileges, the member must be at least 18 years of age and must also demonstrate sufficient knowledge of how to operate the telescope.  Members not desiring key privileges may use the telescope at scheduled events or by observing with someone that has already been issued a key.

At times when public interest was aroused by events, such as Sputnik in 1957, membership was around one hundred or more, but in general we have had about twenty or fewer members.  Dues have been stable for a number of years at $25 per year per family.  Membership is open to anyone who has an interest in astronomy, and who subscribes to the purposes of the Society.  (See our by-laws here.)

A more extensive history can be seen here Note: The total Lunar eclipse of Saturday, November 11, 1956 mentioned in this history actually occurred on Saturday, November 17.  The newspaper article displayed claimed the eclipse would start at 9 PM without specifying the time zone (but New York time was implied).  In fact, the umbral phase started at 10:03 PM MST, and totality started at 11:08 PM MST.  November 11th was a Sunday.  The errors are trivial as far as the purpose of the history is concerned.

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