Short Description of Black Hole Observatory
Black Hole Observatory (BHO) is a small back yard observatory which I built in our garden in Monheim - a small town located between Duesseldorf and Cologne (Germany)- in summer 1996. The massive building is made of pumice and concrete and has a slide-back roof. A detailed description (German text with illustrations) has been published in Sterne und Weltraum 36(5), 483-485, 1997.  Looking onto the figures below you suddenly will realize the naming. The dark painting facilitates dark adaptation for visual observations. In addition to this, it allows for rapid thermal equilibrium of the building. 
Fig. 1 (right) shows the interior view in summer 1997: An 8" SCT (Celstron C8) was mounted in parallel with a 6"-f/12 Maksutov-Cassegrin (Intes MK67) on a German equatorial mount (WAM440CC) from Beat Kohler (Switzerland). The controller is a Sinus II (syn. Powerflex MTS3) from Boxdörfer Electronics. Electronic setting circles and JMI minimax. The MAK served as a guide scope in conventional astrophotography or as a finder scope in CCD imaging (SBIG-ST-7) with the SCT. The floor is covered with black carpet to increase comfort. At this time, dew caps are made of millboard (Pertinax) and equipped with a heating wire inside (look here for better design). 
The paper cited above lacks construction drawings. They are shown on figs. 2 and 3 (below). I payed much attention to pier and foundation. In the chain of rigidity, often the last member, i.e. the connection between pier and foundation, is the weakest. Most important: the center of gravity of the telescope should be as low-lying as possible to allow for high(er) frequencies and small(er) amplitudes of vibrations. The concrete base (including pumice, sand, and gravel) is an irregular pyramid (1.3m deep, 0.6 - 1.2m diameter). Immersed in the center of this pyramid is a big polypropylene sewerage tube of 40cm diameter/2.5cm wall thickness which is also filled with gravel concrete and includes the levelling screws (V2A, M18, 33cm) for the six inch pier (galvanized steel, coated with a zinc-compatible matt black paint. In June 2002, the larger instrument, a C11, asked for an additional meter of sewarage tube filled with 150kg sand to improve damping of vibrations (conf. fig. 4). 
Fig. 1: Black Hole Observatory in 19997
Fig. 2: BHO, sectional drawings
Fig. 3: Sectional drawing of the roof
Fig. 3: Sectional drawing of the roof. Tracks are made of galvanized steel. Rollers (nylon) were obtained from a local store
Fig.2: Black Hole Observatory in summer 2002
Fig. 4: Interior view of BHO in summer 2002.  The 8" SCT has been replaced by an 11"SCT (Celestron-C11; 1:10).  For CCD imaging, an SBIG-ST-7E is used. The camera was bought in the Netherlands in 1998 as ABG-model and, with growing interest in photometry and spectroscopy, converted into an "enhanced" version without anti blooming gate. A Canon 10D DSLR equipped with Nikon-lenses is used for starfields or comets (adapter from Novoflex), a Coolpix 4500 from Nikon for "digiscoping" of sunspots etc. The dew cap is made of polystyrene segments and equipped with a heating wire. For a detailed description of how to make this type of a dew cap please have a look here. The plate on the wall in the background was a birthday gift from the TSO crew. 
Any comments or suggestions are welcome. 
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Copyright: Stapper (1996-2005)