The trailer nose wheels have arrived but I have no 10mm x 65mm, galvanized coach bolts in stock.Galvanized bolts later bought at a builders merchant. The quality was dreadful and I had to try a number of nuts and bolts before I found a reasonable fit. Then they had the temerity to charge me over £1 each!
The next problem is drilling the legs for the wheel jack-post clamps. The pier is so heavy and awkward that it can't be easily set up for accurate drilling. With the box section legs 50mm wide it would be very easy to drill askew. Fortunately the clamps only have two bolt holes each. Some clamps have four corner holes in their base plate which wold have double the work of drilling.
I decided to lean the pier over onto a folding workbench. It was quite a struggle to get it tipped over from upright and then to stop it from crashing down onto the workbench. Once the pier pipe was resting safely on the bench two pier legs remained on the ground for stability. With the third upright and at a comfortable height to be drilled.I marked the first hole to clear large studs in case I wanted it reuse them for stabilizers. A G-cramp held the clamp base plate firmly to the leg while I worked. Once the first bolt was fitted and tightened I inserted and clamped the jacking post and squared it against the leg with a large try-square. The second hole could then be marked and center punched for drilling. I used 5 drills in stepped sizes up to 10mm for each hole. Drilling goes much more quickly this way than trying to force a large drill straight through from the start.
Once the first clamp was fitted the pier could then be brought back upright, tipped between two more legs and the next leg worked on in turn. The final result was an easily moved pier for the first time since I welded it together. With the correct tire pressures the pier does rock when pushed about. Though it is difficult to say whether this would occur with the telescope in use.
There are puncture free wheels available in this size. [Standard sack-truck size.] Which would be considerably more stable but tend to dig in
more on soft grass. I fitted puncture free wheels to the garden
wheelbarrows and quickly discovered their firmness. Nor do the solid foam tires roll so effortlessly as the pneumatic variety. The great advantage is, of course, a complete freedom from punctures when our tall hawthorn and blackthorn hedges have to be clipped. If the pier legs were longer I could have added jacking stabilizers but there is not much room when the trailer wheels have to castor to allow free movement in any direction. Fitting clamps and jacks inboard of the wheels would make rather a small triangle. While moving the wheels inboard of jacks would make the pier much more unstable when being moved about. The stabilizing jacks use the same 48mm clamp size as the wheels.
The images shows the trailer nose wheels fitted with a considerable gain in pier height over the old castors. Handy for ground clearance when viewing near the zenith. I shall have to clearly mark the jack posts to achieve an average height before jacking up the pier. Even in daylight it is difficult to judge. I shall also have to dismantle the jacks and grease the threads since they seem rather stiff. The wheel's roller bearings were not lubricated either when I removed a wheel to gain better access to the valve.
The temporary 8" tube rings are simple alloy straps to allow me to hang the tube while I wait for new rings to arrive. It started raining
just as I finished so I had to put the tools away in a hurry. So there
was no chance to take any more images.I shall have to consider the pros and cons of different types of storage. If the OTA could be permanently mounted it would greatly increase the chance of observation under a clearing sky. The sheer inertia of lifting a heavy OTA onto the high mounting has always been a huge hurdle to observing on a sudden whim. Even worse was the thought of getting it back down again when it was wet with dew or covered in a film of ice or white frost.
Short of a lottery win, a suitably large, commercial dome is completely out of the question. The latest Pulsar 3.5m dome costs somewhere around £7k by the time it is delivered and erected on a suitable observatory wall or flat-roofed building.
I have often considered a
[semi-cylindrical] rotating, barrel-roofed plywood "dome" as ideal for a long refractor. The gentle bending
radius of the roof is easily within the range of 4 or 6mm BWP birch plywood. Though the "dome's"
finished weight would probably require a good number of skate wheels to
support it with low enough rotational friction. The inertia might prove a
burden for manual rotation. Aluminium would be much lighter but I have no
idea where to obtain enough material for a 10' x 10' half cylinder at low cost. A half cylinder would require at least four 8'x4' sheets of material plus the shutter materials and two semicircular ends. I suffered from years of shoulder pain due to industrial repetitive strain injury. This severely hampered my ability to lift anything above shoulder height. Nor do stepladders lend themselves to loading an OTA onto a high mounting. The stepladders always gets in the way of the pier or its legs however they are arranged. Climbing the ladder without a free hand requires the balancing skills of an acrobat. Metal, U-shaped drawer handles greatly reduce the risk of dropping the OTA but do not make it any lighter. Nor less cumbersome while climbing a ladder.
Click on any image for an enlargement.
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