I tried to keep tabs on cost throughout the one year project of building this telescope shelter. Here is a summary of those costs (15% sales tax included). Please note these are in Canadian dollars.
- Cement Foundation: $134
- Cement Floor: $130
- Tubular Frame: $390
- Aluminium skin: $0
- Lock: $40
- Paint/Sealants: $124
- Foam panel insulation: $122
- Electricity: $196
- Gas springs; Desk: $170
Total: $1,305 CAD (approx = $977 USD*)
* Current exchange rate (Dec 2015): is about 1 $USD = 1.35 $CAD.
Of course, as usual, the project ended up costing much more than I had initialy anticipated. I was expecting something closer to $700 CAD when I initialy planned the project. At the time I had not counted on painting the cover (but the aluminium ended up being to ugly); I had not thought of the gas springs being necessary, the desk was also a last minute idea. Also, all the bolts and attachements are either stainleess steel or galvanized.
Here are a few things I learned and things I would do differently knowing what I now know:
- A classic: dig the trench and install the underground cables before installing the foundation
- Insulation: I’m glad I insulated with R5 foam panels, it will help to control relative humidity during cold seasons with just a little heat. However I should have also added a reflective barrier for solar radiation. It’s not too late and I plan on adding a highly reflective aluminium barrier on top of the foam insulation to push back whatever solar heat will have made it’s way past the insulation.
- Keep the floor free of obstacles you could trip on during the night. By clever improvisation I was lucky in keeping the floor smooth and free of obstacles. The only one left is the two locking brackets attached to the floor, just south of the telescope. Even though they are fairly close to the telescope (about 8 inches away) I keep triping over them. Next spring I will modify them so they are also under the floor, by milling away the square tubings on each side of the floor to accomodate the locking pin. I will also lengthen the pivoting, hooked bracket attached to the cover so it can reach further down, to lock.
- I have not decided yet if I want to extend the patio around the current floor. It would be nice to have a level floor with no grass. It would make placing and moving an observing chair easier. But the cement would accumulate heat and release it during the evening. Grass does not do that.
I’m very happy with the way things turned out with this project. It pretty much meets my goal to have good protection for my largest scope at a fair price. For a dobsonian type Netwonian telescope between 10 and 30 inches, I think this is an excellent option over a ROR or a rolling structure. This type of instrument looses sky accessibility unless walls are very low, when stored in an ROR. Why not get rid of the walls altogether, which is what I did here.
It could be made much smaller for a smaller telescope, of course. At a certain point, if the cover were small and light enough, gas springs would not be necessary reducing the expense. A simpler padlock could also be incorporated instead of the more complicated internal lock I built.
I hope the information contained in these pages will spark interest in this shelter design and provide a lower cost alternative for those wishing to have access to their instrument with a minimum of effort.