The Observatory
Location
The following considerations were examined to select the location:
- Enough space
- The north celestial pole had to be visible to easily perform polar alignment
- Enough available sky area
- No objects like electrical wires, trees and houses block the sky area
The observatory would be installed behind the garage next to the house. It was not ideal because only the north, east and south-east is cleared from trees and structures.
Design
Three different options considered for the observatory design:
- Ready-made dome or roll-off roof like the ones from Skyshed;
- Build roll-off roof observatory;
- Buy a PVC garden shed and modify roof so it can open.
After a lot of internet researches and cost estimation exercises, The PVC garden shed was opted for. It was cheap ($700 CDN), quick and easy to install, easy to modify, would last a long time (the PVC is almost unaffected by the climatic conditions and sun) and it didn’t look like an observatory (Better blending with the backyard’s look and feel).
Construction
A deck was built to elevate observatory a few feet from the ground to gain sky coverage. A 14′ by 16′ deck was constructed. A treated wood wall was also added to block stray light from the street.
While the deck was still under construction, a hole (12″ wide by 48″ deep) was dug for the concrete base for the telescope pier.
During the first winter, the deck suffered from structural problem because two of the sides were solidly screwed to house and garage walls while the deck itself was resting on concrete foots. The deck was almost damaged when the ground raised a few inches due to soil water freezing. When spring came, concrete foots were replaced with 51″ helical metal piers screwed in the ground.
Once the foundation repaired, a Home Depot 7′ X 7′ PVC garden shed was purchased. A hole was made on the shed’s floor. A mosquito net installed around the pier to keep insects and rodents out but still offer good ventilation. Hinges were installed on the two roof panels which were re-enforced them with metal braces and retaining cables were installed.
At that point, the opening and the closing of the roof was still manual.
Since then, the roof was motorized and computerized and made ASCOM compliant so it could be controlled automation software.
The observatory control computer stay in the observatory all year long thanks to a homemade heated enclosure. This make sure that the computer components never reach the freezing point and can be used in any temperature.
In the spring of 2013, the pier concrete base had to be re-positioned after having suffered from severe displacement due to soil freeze. The entire observatory had to be moved aside, the deck had to be opened in order to get access to the base and make the necessary corrections. The soil in the region is made of mostly clay. During winter, the water in the clay expand due to freezing. When soil thaw, the clay retracts and leave space between the the concrete base and the soil. The pier then tilts. To make the repairs, the pier was leveled, braced and rock dust (i.e. 2 full bags) packed in the space for two hours (see images).
In the spring 2014 the pier was still suffering from tilt due to freezing. Four helical metal piers were installed around the existing concrete pier base. A 4′ x 4′ casing was constructed and laid down on the four piers. It was then filled with an additional 13,000 pounds of concrete. This new floating slab was glued and rebar(ed) to the existing concrete footing. The metal pier has been screwed to this new footing and have not moved sin
