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Old 17-06-2017, 11:00 AM
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Nebulous (Chris)
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DIY Astro-trolley

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…

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):
  1. 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.

  2. 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).

  3. 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?...

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.

Cheers,

Chris
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Old 17-06-2017, 11:30 AM
glend (Glen)
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Great idea, and multi purpose too. However, unsealed MDF is the weak link, it will absorb dew like a sponge, and eventually begin to flake and breakdown. Marine ply would be ideal. If you stick with MDF then seal it top and bottom and sides with a good waterproof sealant coating.
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Old 17-06-2017, 12:32 PM
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Nebulous (Chris)
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Quote:
Originally Posted by glend View Post
Great idea, and multi purpose too. However, unsealed MDF is the weak link, it will absorb dew like a sponge, and eventually begin to flake and breakdown. Marine ply would be ideal. If you stick with MDF then seal it top and bottom and sides with a good waterproof sealant coating.
Thanks Glen. You're right of course, and I'll get around to it eventually. I do have various cans of sealant, but it may take a minor wetting to prompt me into action.

I did consider marine ply when getting the supplies but for my modest use I really couldn't justify the extra cost. I mostly set up for about an hour's viewing, reasonably early in the evening and the location doesn't seem especially prone to dew, although I can recall a longer occasion when the table I had set up was half in the shed and half out and it was dry one end but starting to get wet at the other.

But these are lame excuses.... and a coat of something would look good too. I'll add it to the list...
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Old 17-06-2017, 01:33 PM
Wavytone
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Hi Chris, Nice first try.

I made one many years ago and found wide wheels roll much more easily - and smoothly over gravel as well as grass, skinny wheels are pretty awful.

The wheels on mine were cannibalised from a toddlers tricycle. The base was cut from a solid core door, which in those days meant solid pine sandwich with plywood on other side. With 3 coats of marine varnish, it survived being outside perfectly for several years despite the frost and dew usual in Canberra winters.

Agree re MDF - its hopeless with any kind of moisture starting with dew, and exposed to rain or frost it will disintegrate fast.

By the way the tripod was made from karri floorboards (very hard wood, like jarrah) and was excellent. The scopes are a 6" f/8 Newtonian (top) and a 6" f/18 folded newtonian (square tube under). The mount was an old Astro-Optics "Goliath" with a homemade 8" worm.
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Old 17-06-2017, 06:15 PM
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iborg (Philip)
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Hi

Looks good. When you get to the Deluxe model, don't forget the double overhead underhang and chrome plated grease nipples!

Philip
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Old 17-06-2017, 07:25 PM
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Quote:
Originally Posted by Wavytone;1316987.

By the way the tripod was made from karri floorboards (very hard wood, like jarrah) and was excellent. The scopes are a 6" f/8 Newtonian (top) and a 6" f/18 folded newtonian (square tube under). The mount was an old Astro-Optics "Goliath" with a homemade 8" worm.
Great looking rig. Bags of character and an intriguing tripod and mount too.
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Old 17-06-2017, 07:26 PM
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Originally Posted by iborg View Post

Looks good. When you get to the Deluxe model, don't forget the double overhead underhang and chrome plated grease nipples!

Philip
I'm taking notes now...
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Old 18-06-2017, 06:34 AM
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I noticed many 3 wheel prams often have large wheels with the front steerable. Always seeing them abandoned in curbside clean ups...
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Old 18-06-2017, 09:36 AM
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I noticed many 3 wheel prams often have large wheels with the front steerable. Always seeing them abandoned in curbside clean ups...
Good idea. A friend of mine is a keen scavenger from curbsides and scored some similar wheels that he fitted to his lawnmower so that he could more easily steer it into some awkward corners on his lawn. He also built a beautiful wooden rowing boat (full sized) from salvaged packing crates. Not exactly marine grade stuff but with a few coats of a good sealant it works a treat.
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Old 18-06-2017, 12:18 PM
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Now…… what colour scheme would suit an Astro-trolley? Suggestions?

A nice dark blue with some added stars? Matt black with flames down the side? A clear finish? Or perhaps some more discreet colours to match the rest of the “Observatory”? It only has to travel about two metres from the shed to the observing position - and it won’t be entering any ‘Show and Shine’ events - so pretty much anything from a left over can in the shed should do the job.

And just to prove that I actually can finish things - here’s a couple of shots of the “Observatory” (aka my house and sheds). It was another DIY project that I built nearly 30 years ago now (I’d always fancied having a go at a whole house). I even went so far as to make all the doors and windows myself out of oregon, using old fashioned wedged mortice and tenon joints (a satisfying but very time consuming project). And it hasn’t fallen down, cracked or rotted yet. Unlike the owner builder who is getting decidedly tatty now, and overdue for extensive renovations before the rapidly approaching use-by date arrives....

Painting the Astro-trolley in colours to match the "Observatory" is currently firming in the betting. Maybe the green from the trim. Not such much as a design statement but more a way to use up existing stock and avoid the need to buy any more tins ....

EDIT: The trolley has now been painted in colours to match the "Observatory". I was not having one of my better painting days so I applied a fair bit of it to myself as well.... But at least the buildings, the trolley and me are all now colour coordinated..
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Old 18-06-2017, 03:46 PM
Wavytone
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Depends ... if your carpentry is good and the wood is attractive then a clear finish for sure.

Otherwise I'm inclined to suggest painting in a pale colour so you don't trip over it in the dark.
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Old 18-06-2017, 11:00 PM
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mswhin63 (Malcolm)
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It seems my opportunity to build and Observatory is limited, so this seems like a good idea for myself.

Thanks for the inspiration.

Cheers
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Old 26-06-2017, 02:41 PM
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I use a cheap tripod dolly I got on ebay for my 6in scope and would like something stronger to get my 11" back into use. My stroke left me without the use of one arm and the dolly has allowed me to continue enjoying astronomy in my limited capacity. So I compromised by configuring my setup once in the garage at my leisure and wheel it outside to use, no messing about changing/swapping stuff in the dark.

But for me I also have sloping ground and to get back to using my scopeasaurus I would need something like this with a hand control to guide it outside without it running away and operational brakes from the hand too to ensure it stays put. the foot things are a bit of problem. I did find a guy in america who made an electric tripd dolly rig for large scope tripods with a hand control, but still way beyond my price range. Anyone have ideas for wheels with hand controlable/lockable breaks? The OP's triangle platform thing I could hinge a plank to that to serve to steer a rig in/out but would need to have brake controls on the end of the plank too. ideally good wheels for any direction smooth travel, not shopping trolley steering. I could probably build something maybe and would also need to consider the platform should pretty much hug the ground, i'm unsure how high my scope would be when reassembled and if it would even clear the garage door. But its EQ so I may need to rework my "home" position for it. It'll be a long term project for me, money is still a struggle, but I really dont want to give up on being able to do some imaging with my main scope or just sell it.

I know some forklifts now have those strange wheels that can let you move omnidirectional and maybe something like that would be good but probably expensive. I assume they need powering and a control unit too. I think something with a good cable operated break system so i can control it on down slope without it running down into neighbours living room. maybe anti antigrav hoverboard of some kind? for a fiver? with mind control steering?
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Old 26-06-2017, 06:42 PM
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But for me I also have sloping ground and to get back to using my scopeasaurus I would need something like this with a hand control to guide it outside without it running away and operational brakes from the hand too to ensure it stays put. the foot things are a bit of problem. I did find a guy in america who made an electric tripd dolly rig for large scope tripods with a hand control, but still way beyond my price range. Anyone have ideas for wheels with hand controlable/lockable breaks?

Hi Sil,

Independent Living Centres can be a good source of ideas as they supply all manner of devices like wheeled walkers with hand operated brakes which could be burgled for bits or "remade" if you could get something second hand. I have a friend who is very talented at that kind of recycling and rebuilding but he lives in Perth, so not much use to you unfortunately.

http://ilcaustralia.org.au/search_category_paths/13

There are also commercially available trolleys with hand operated brakes, but I imagine they're not cheap. There are even powered options, but I suspect the price of those would make our eyes water...

This is an unpowered example with a "dead man's brake" - i.e. it only rolls when you squeeze the bar - if you let go it stops.

http://www.tentecastorsandwheels.com...-NFWB301).aspx

Commercial materials handling stuff tends to be a bit pricey, but they may have a suitable trade-in, or know where you might be able to get something second hand and more affordable.

Sorry I can't suggest anything more accurately targeted. Best of luck with the hunt.
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Old 29-06-2017, 12:47 PM
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I like the dead man brake idea. Surely spare parts can be bought separately. Probably more trouble me tryting to build something that won't fall apart under the weight of the scope (80+ kg) and just hope I can save enough one day and contact the guy in the states who makes them and let him sort oout a braking solution.

I spent a few months in an independent living unit after the hospital ward. Noone of that gear would suit the weight and stability, like most disability aides to normal people they sound good, but when you have to rely on them to do their job you quickly realise they are expensive and useless.
Its a very captive market (in all definition) and little to no choices and often the health care system requires you to buy certain equipment otherwise they cease treatment.

I think a solution lies in industrial sectors, not medical. Hand jacks I used to use when factory worker were fun, could take the weight I cant recall brakes on the powered jack, it was just so heavy I think it only had throttle. I couldnt see anything in that sector though that might suit my needs and ground . But I had to ask, never know someone here might run a junk yard and be able to knock something up from spares during a coffee break (its ALL coffee break right?) Otherwise I can see a solution and its just a matter of dollars to get there and at least might be possible for me to get there unlike treatment which is far too far away.
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Old 29-06-2017, 10:34 PM
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OzEclipse (Joe Cali)
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Quote:
Originally Posted by sil View Post
I use a cheap tripod dolly I got on ebay for my 6in scope and would like something stronger to get my 11" back into use. My stroke left me without the use of one arm and the dolly has allowed me to continue enjoying astronomy in my limited capacity. So I compromised by configuring my setup once in the garage at my leisure and wheel it outside to use, no messing about changing/swapping stuff in the dark.

But for me I also have sloping ground and to get back to using my scopeasaurus I would need something like this with a hand control to guide it outside without it running away and operational brakes from the hand too to ensure it stays put.
Hi Sil,

Rather than moving a heavy scope a long way down and up a slope, what about a lightweight weather cover that rolls s short distance off the 11" which you leave permanently set up in your back yard. Unlike an observatory, it doesn't have to take up a lot of space nor be much bigger foot print than the instrument. Put a solar panel on the top and charge a battery that lives inside. That weight can lower the center of gravity. Keep it stable as it rolls.

Joe
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Old 30-06-2017, 12:08 PM
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Joe wish I could. I live in a townhouse, two storey, tiny rear courtyard with a very happy garden I enjoy and consequently little sky view (the trees get happier each year!). I consudered sacrifycing part to an observatory but cant bring myself to do that, took me ages to get the plants to take hold and attract the birds etc.If my place was facing 90deg to the left I would have converted one of the upstairs rooms to an observatory as it has floor to ceiling glass doors, not ideal but safe and cosy . Anyway I'm only talking a distance of 10ft but in my situation it may as well be 10km crawling on broken glass with my zip open. Its a complex too so I am limited to construction possibilites, an observatory on the roof would be cool Something using an antiairfact gun mount so i can recline in comfort and swivel in any direction to shoot the sky plus lots of lasers. You know the usual stuff
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Old 30-06-2017, 12:56 PM
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Otherwise I can see a solution and its just a matter of dollars to get there and at least might be possible for me to get there .
That’s true. A friend of ours who was dealing with yet another domestic drama (they had 5 kids) once said to me “There’s always a solution to our family problems….(pause)… and it’s always the SAME solution….(pause)…. spend more money!”. He’s probably right.

There could be another option. I believe that there are some Men’s Sheds in the Canberra area and they might be willing to take it on as a project. We have a local shed and they have quite a range of capabilities. Some of the members are probably old codgers wanting to try their hand at a bit of basic carpentry, with mixed results, but amongst them there are also some really good retired wood and metal workers. Men's Sheds may charge for some tasks and do others for free - I don’t know. I imagine there’s a big variety among the various shed memberships. Might be worth asking around anyway.
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Old 01-07-2017, 02:56 PM
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Sil,

OK a solution does come to mind.

1. Approach body corporate with a request to install a skylight in the roof. A bloody big one, and one that opens (from memory there is one) so you're not looking through two glass panes.

2. Aquire a large optically flat mirror, say 25-32 cm across to use as a siderostat. Set this up on a mount that sits on the roof directing a beam of light through the skylight.

This needs a compact horseshoe mount allowing it to tilt (declination) and rotate in RA to track. It could probably be cannibalised from a commercial mount, say an EQ6, with some work.

The mirror mount also needs to be motorised so in this respect a GOTO mount is probably the ideal donor to be cannibalised, and some electronics surgery is required.

3. Set up a nice scope of your choice inside, pointed at the flat, under the skylight. The beauty of this is the scope is stationary, and you're inside out of the cold Canberra winter.
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Old 02-07-2017, 01:05 PM
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J Dobson

Quote:
Originally Posted by Wavytone View Post
Sil,

OK a solution does come to mind.

1. Approach body corporate with a request to install a skylight in the roof. A bloody big one, and one that opens (from memory there is one) so you're not looking through two glass panes.

2. Aquire a large optically flat mirror, say 25-32 cm across to use as a siderostat. Set this up on a mount that sits on the roof directing a beam of light through the skylight.

This needs a compact horseshoe mount allowing it to tilt (declination) and rotate in RA to track. It could probably be cannibalised from a commercial mount, say an EQ6, with some work.

The mirror mount also needs to be motorised so in this respect a GOTO mount is probably the ideal donor to be cannibalised, and some electronics surgery is required.

3. Set up a nice scope of your choice inside, pointed at the flat, under the skylight. The beauty of this is the scope is stationary, and you're inside out of the cold Canberra winter.
Sil,

The is some footage on YouTube of John Dobson's beautiful and VERY big Camera Obscura. Upon investigation, the whole idea/concept of a large Camera Obscra is very intriguing.
With the Tech that's so readily available the Camera Obscura concept may prove to offer many answers requiring only a flexible mind!
Cheers
David
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