Nebulous
17-06-2017, 12:00 PM
A Cautionary Tale
Hi all,
I’d love to have a dedicated observatory with sliding roof, built in armchair, bar and all the trimmings but, alas, there is no suitable spot here to build one. The clear spots already have buildings on them and the free spots have too many trees in the way. The best position is on the driveway in front of the garage/shed. So that’s where I usually do a temporary set up. It works OK too, but I’m now in my seventies, with a dodgy back, and lugging gear in and out of sheds and setting things up in the gloom does get tedious quickly.
Or maybe I’m just getting lazy and like fiddling about in the shed building stuff… :rolleyes:
But, if I can’t have a fancy roof that rolls back, why not build a floor that rolls out instead?
The weak point in that idea might be stability. However, I don’t do the sort of observing that requires highly accurate tracking, or photography that uses multiple timed shots. I mostly enjoy star hopping, finding particular targets to view, and learning the layout of constellations. So a fairly simple trolley should do the job.
The result was to make a triangular trolley, with a locking brake on each wheel. I can set everything up inside the Mancave and then gently push it out. The deep sides give it rigidity and also prevent a tripod leg getting nudged off in the dark.
Triangular for several reasons (which you’d probably all have guessed):
It’s the most stable configuration. Just like a tripod, it can be placed on relatively uneven ground and it won’t rock. Unlike a 4 wheel trolley which, unless the ground is billiard table flat, will always have one wheel off or nearly off the ground.
A tripod mounted scope will fit neatly on it (leaving plenty of free space for trays of accessories such as torch, ipad, eyepieces, glass of Scottish warming fluid, etc).
I could use a 3m long piece of wood that I already had, and only needed to buy three wheels not four. Satisfying when you’re something of a tightwad when it comes to buying new supplies…
If I do ever need accurate levelling I can use adjustable devices in each corner (basically threaded bolts on brackets). Provided I put a wheel on the highest point, only two levelling bolts will be needed at most, but each side has a bracket anyway. And despite what you might think from the picture, bolts that thick don’t bend or buckle and even with the nuts only nipped up finger tight they stay upright with no leaning to the side.
Probably not for everybody, but I had a lot of fun making it.
Cutting the angle is the only part that might be potentially difficult but my bench saw has a blade that can be tilted. When it was set to 30 degrees from the vertical, the result was a piece of wood with a 60 degree angle.
Using one 60 degree angle at the join rather than two at 30 degrees was easier to cut and assemble and probably stronger than using a 30 degree cut on each piece. And I did a test on some scrap wood first to make sure the angles were spot on rather than just approximate..
The 100mm (4”) wheels handle the rough ground OK but the lack of suspension means that a slow pace is needed to avoid vibration issues. The Deluxe model will probably have pneumatic tyres, rally suspension, disc brakes, some kind of turbocharged motor, GPS, bucket seats, etc….
The irony of the situation was that it was designed as a platform to carry a tripod mounted rig. But once it was built I wondered how big the potential circle in the middle of the triangle might be…. With the aid of a large dustbin lid I was able to establish that anything up to 53 cms in diameter would fit comfortably. Google told me that the base of an 8” SkyWatcher Dobsonian measures 52 cms, but data from SkyWatcher on the current base size of the (secretly coveted) 10” model was harder to find, although a couple of sources suggested it was also 52 cms.
However, the friendly owner of the Midland Camera House told me that he had a 10” in his warehouse and offered to bring it into the shop where we could open the box together and measure it. So we did, and it turned out to also be 52 cms. :) And after he’d gone to all that trouble, and offered me a decent price as well, it seemed only polite to buy it. What else could I do?...:shrug:
And it fits a treat too. So last night I had a choice - evict the Dobsonian and put the tripod back on, or temporarily take the counterweights off the tripod mount while I carried it outside….. The Dobsonian sat there like a big cuckoo in a nest and dared me to try and lift it off again…. So I took the weights off the tripod mounted scope and carried it outside... And, hey, it wasn’t that hard really. And, boy, do those 10” telescopes scoop up a fine looking bucketful of stars. :D
Cheers,
Chris
Hi all,
I’d love to have a dedicated observatory with sliding roof, built in armchair, bar and all the trimmings but, alas, there is no suitable spot here to build one. The clear spots already have buildings on them and the free spots have too many trees in the way. The best position is on the driveway in front of the garage/shed. So that’s where I usually do a temporary set up. It works OK too, but I’m now in my seventies, with a dodgy back, and lugging gear in and out of sheds and setting things up in the gloom does get tedious quickly.
Or maybe I’m just getting lazy and like fiddling about in the shed building stuff… :rolleyes:
But, if I can’t have a fancy roof that rolls back, why not build a floor that rolls out instead?
The weak point in that idea might be stability. However, I don’t do the sort of observing that requires highly accurate tracking, or photography that uses multiple timed shots. I mostly enjoy star hopping, finding particular targets to view, and learning the layout of constellations. So a fairly simple trolley should do the job.
The result was to make a triangular trolley, with a locking brake on each wheel. I can set everything up inside the Mancave and then gently push it out. The deep sides give it rigidity and also prevent a tripod leg getting nudged off in the dark.
Triangular for several reasons (which you’d probably all have guessed):
It’s the most stable configuration. Just like a tripod, it can be placed on relatively uneven ground and it won’t rock. Unlike a 4 wheel trolley which, unless the ground is billiard table flat, will always have one wheel off or nearly off the ground.
A tripod mounted scope will fit neatly on it (leaving plenty of free space for trays of accessories such as torch, ipad, eyepieces, glass of Scottish warming fluid, etc).
I could use a 3m long piece of wood that I already had, and only needed to buy three wheels not four. Satisfying when you’re something of a tightwad when it comes to buying new supplies…
If I do ever need accurate levelling I can use adjustable devices in each corner (basically threaded bolts on brackets). Provided I put a wheel on the highest point, only two levelling bolts will be needed at most, but each side has a bracket anyway. And despite what you might think from the picture, bolts that thick don’t bend or buckle and even with the nuts only nipped up finger tight they stay upright with no leaning to the side.
Probably not for everybody, but I had a lot of fun making it.
Cutting the angle is the only part that might be potentially difficult but my bench saw has a blade that can be tilted. When it was set to 30 degrees from the vertical, the result was a piece of wood with a 60 degree angle.
Using one 60 degree angle at the join rather than two at 30 degrees was easier to cut and assemble and probably stronger than using a 30 degree cut on each piece. And I did a test on some scrap wood first to make sure the angles were spot on rather than just approximate..
The 100mm (4”) wheels handle the rough ground OK but the lack of suspension means that a slow pace is needed to avoid vibration issues. The Deluxe model will probably have pneumatic tyres, rally suspension, disc brakes, some kind of turbocharged motor, GPS, bucket seats, etc….
The irony of the situation was that it was designed as a platform to carry a tripod mounted rig. But once it was built I wondered how big the potential circle in the middle of the triangle might be…. With the aid of a large dustbin lid I was able to establish that anything up to 53 cms in diameter would fit comfortably. Google told me that the base of an 8” SkyWatcher Dobsonian measures 52 cms, but data from SkyWatcher on the current base size of the (secretly coveted) 10” model was harder to find, although a couple of sources suggested it was also 52 cms.
However, the friendly owner of the Midland Camera House told me that he had a 10” in his warehouse and offered to bring it into the shop where we could open the box together and measure it. So we did, and it turned out to also be 52 cms. :) And after he’d gone to all that trouble, and offered me a decent price as well, it seemed only polite to buy it. What else could I do?...:shrug:
And it fits a treat too. So last night I had a choice - evict the Dobsonian and put the tripod back on, or temporarily take the counterweights off the tripod mount while I carried it outside….. The Dobsonian sat there like a big cuckoo in a nest and dared me to try and lift it off again…. So I took the weights off the tripod mounted scope and carried it outside... And, hey, it wasn’t that hard really. And, boy, do those 10” telescopes scoop up a fine looking bucketful of stars. :D
Cheers,
Chris