Step 1
Decide on a site, this is probably the most important decision of the whole project as it will make or break the usefulness of your finished observatory.
Check the field of visibility and ensure that you have good 360� field of view. Make sure all hedges and trees are considered (remember that trees and bushed are bigger and a greater obstruction with leaves on) and that they will inevitably grow. Also take into account any security lighting and light pollution.
At this point you will have to decide which direction you can allow 25 � from the horizon to lose for when run off observatory is open.
Always talk to your neighbours and tell them what you are proposing to do and what the finished dimensions will be.
Step 2
Sink a 10-inch plastic pipe into a concrete base and fill it with concrete. It is vital the pier is absolutely level and stable to ensure accurate telescope alignment later and that it is at least 1.5 metres into the ground with adequate height above ground for the telescope to be installed at the optimum observing height.
The pier should be positioned so that when a telescope is parked it does not interfere with the run off operation.
A ready-made pier can be purchased but they are expensive and will take half the budget.
Step 3
Cut the shed base around the pier leaving � inch gap all the way round to minimise vibration form the shed to the pier. Then lay onto a base of paving slabs. Although the paving slabs are not vital to the project they do make things a lot easier later. Levels must be accurate at this stage to ensure that the shed and run off rails can be installed properly.
Step 4
Adapt the lower half of the shed by removing anything that would obstruct the run off. If you have the type of shed where the walls are in 2 stages then any connecting clips that stick out must be sawn level. If not then cut at a suitable height for the pier. Fit additional bracing to all edges and joints and bolt the sections together. If you can get stainless steel fixings all the better.
Make sure that you reinforce all wherever possible as the structural integrity of the shed is now severely compromised and does require the additional support. The rear wall requires cut outs to take the rails with enough spare to allow for the wheels to pass through easily.
Step 5
Fix steel uprights at each internal corner to take the rails. The uprights should be screwed onto the lower wall sections only to hold them in place not for the wall to take any of the weight. It is a good idea to strengthen further by connecting the rear 2 uprights together. Make sure that the uprights are all level and vertical and at the correct height to take the rail through the rear wall.
Step 6
Install the run off rails onto the steel uprights. Any bolt or screw heads should be countersunk into the rail to prevent them from obstructing the run off later.
Outside at the end of the rails bolt them onto wooden fence posts countersinking the ends as before.
It is best to use metaposts bolted onto concrete pads for the posts as it gives greater stability and will be easier to maintain or replace in the future..
The rails must be long enough to allow complete removal of the top from the base and a backstop should be fitted to the end of the rails to prevent the top falling off the end, especially on a slope and to stop the rails leaning in.
Great care and attention to detail is required at this point to ensure the rails are level and correctly spaced. If they are not then the run off procedure will be impossible
Step 7
Adapt the upper part of the shed as for the base and fit the wheels through the upper walls using threaded rod. It may be necessary to pack the wheels out for them all to run in line. Ensure that the upper section is raised to a maximum of 5 mm from the base when the wheels are on the rails. Use self-adhesive damp proof strip on the outside to cover the gap additionally screw the strip to the top section to keep in place.
Step 8
Install a suitable amount of power points into the observatory. For safety reasons it is important that you use armoured cable and weatherproof sockets. Also fit any shelving and accessory trays around the walls ideally hinging them from the wall to fold down out of the way when not required. Small-wheeled tables are also very useful for putting laptop computers on as they can then be easily moved around during the session.
Step 9
Fix lock down points to ensure the top does not blow away in the inevitable gales we have but make sure that they can be easily removed and replaced in the dark. It is also a good idea to put a wedge under one wheel each side to prevent the trop moving and put a wedge each side under a wheel.
Adapt the doors so that they can be easily removed or slid back to allow the run off operation. Make sure that any fixing lugs or bolts are easy to locate in the dark and that they are strong enough to do the job. I found that old fitted kitchen leg height adapters were ideal. Remember that the doors will still have to secure when the observatory is closed up.
Step 10
Use a security padlock to lock the observatory and you should also consider fitting an intruder alarm just to be on the safe side. You must check with your Insurance Company that your telescope and equipment is covered when it is left in the observatory.
Step 11
Install the equatorial wedge or appropriate telescope mount onto the pier and align as accurately as possible. And finally mount a telescope and start observing.
Notes
If you need to raise the rail height after construction then UPVC window strip obtainable in various thicknesses can be purchased from you local UPVC window suppliers. This is simply glued onto the rail.