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Roof Top Observatory

Details of the construction of a roof top observatory by one of our members.

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It didn't take many occasions like this to convince me that i needed an observatory!!!
Design
While undertaking a major loft conversion I identified an area in my plans that would be just large enough for a small observatory. Planning permission was required and given by our local council and parish council. The design entailed a purpose built dome constructed using a softwood frame with a 6mm ply covering. This was then finished by coating with fibre glass. CAD was employed to produce accurate drawings of the proposed dome and these were used in the workshop to manufacture all of the dome components. At the design stage close attention was paid to the weathering details as the dome would be exposed to strong winds and rain.
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Construction

All dimensions were taken directly from the CAD drawing to produce mdf patterns and full size layout and arcs. The curved compenents were all produced by glueing and screwing overlapping pieces. The curvature during this process was controlled by laying them over the full size drawn arcs thereby ensuring the correct radius for the completed component. The overall lengths of the ribs and the setting out of their ends (the precise shape to allow them to butt up accurately at the joints) was all derived from the full size layouts and the CAD drawing. Each component was precisely located and glued and screwed into position. Plywood 'pettels' were cut then glued and screwed into position over the ribs. The opening upstand was fitted and the outer ply skin filled and sanded. The shutter panels and base ring were all made up using similar methodology. Finally, the the dome, shutters and base ring were all fibre glass coated.
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Installation

The base for the dome was a timber frame construction and fully insulated. The inside being plaster boarded and skim coated and the outside weather boarded. The base ring fitted over the top of this structure and close attention was given to the flashing details to ensure that rain and snow would never penetrate. The dome was man handled into position and the shuters installed. A steel beam straddles two supporting walls and the telescope is bolted to this.
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Conclusions

At the time of writing this the observatory has now been in operation for over eight years and in that time it has never leaked once. The original telescope (C8 fork mount) has since been upgraded (with the help of a Ridley grant) to a C9.25 go to fork mount. In that time a wide range of observations have been carried out. Most of these have been in the form of time series photometry to produce light curves for variable stars, asteriods and, in recent years, exoplanets.
All in all the observatory has been a great success even if the location is not ideal being so near London and the M25.



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Page edited 9 times. Last edit by - Lynx2910 Lynx2910 on Oct 14, 2014 7:29 am. This site contains 560 pages
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