I've managed to source locally some 273 mm (10.7") OD pipe with a thickness of 4.8 mm. I'll need to do some calculations myself but my questions run as follows.
1. Is this too large a diameter for a permanent pier that will for several years support a HEQ5-Pro with a SW BD ED120 refractor?
2. Would a pier of that diameter obstruct the scope and mount when viewing near the zenith?
3. Has anyone else used pipe of this size to make a pier themselves?
Any advice would be much appreciated.
Paul
Last edited by pfitzgerald; 04-07-2014 at 03:38 PM.
I've read the aricle by Dennis Persyk - "Pier Design Fundamentals" from the Cloudy Nights website and a 48" (122 cm) pier has a deflection of about 0.6 arc seconds.
One concern which I've now added to my questions is, "Would a pier of that diameter obstruct the scope and mount when viewing near the zenith?"
Hence my need for advice and performing some calculations before pressing onwards and upwards!
Yours is one serious hunk of metal!
Paul
PS What are you going to use for the top plate? I'm thinking of using a car disk brake with appropriate dimensions.
I use an 8inch steel pipe at my dark site. When imaging it still points to the zenith and the filter wheel USB cable is only just clearing the pipe. An extra 1 inch wouldn't amount to much. The GEM arm sticks out a bit so its not right next to the tube.
I'd hazard that you would be fine. 8 inches definitely works.
I'd get a piece of cardboard and make a tube 8" in diameter, cut to the appropriate height and drop it over your existing tripod . Then you can try it with your own setup and be sure.
I'm using a 10" upended concrete pipe as a pier for EQ6 and whatever it will carry. It's secured to the concrete slab with a 1 meter M12 threaded rod and works just fine.
Go for it.
I spent time over the weekend designing what I want. I'll make a cardboard mock up this week to see what it will look like, and to check how it goes near the zenith. Once that is done I'll post up the plans for discussion.
Thanks everyone for your input thus far as it is much appreciated.
Here you go, one pic tells a lot more. That's a 10" dia pipe going through a floating floor onto a big slab of concrete. The bottom end is belled to accept an adjoining pipe, about 300mm I think so pretty stable. EQ5 and a 10" Newt on board, no problem.
It was in the backyard when we bought the house, about 900 mm long. It's a bit short actually in the Ob and I'm in the process of building a 'top hat' to get me a better look over the edge of the roofline.
Cutting one would need an angle grinder and a few masonry blades maybe. There is some reinforcing mesh inside.
Hey, where do you live ? Header says about 4 km away from me. I'm over in Mt Albert.
Aha ! A Westie !! Must catch up some time. I've just joined Auckland Astronomical Society so I can find a few like minded people. Share some ideas and resources. Find some ideas.
If your interested in having a look at SkySlab give us a yell. I just about finished reroofing it so the rest of the hardware is going back in over the next week or so. Thread here with picture. http://www.iceinspace.com.au/forum/s...d.php?t=123058
Haha. Not quite a Westie but we have enough V8's and blue tarps to blend in if we need to.
I'm a bit busy just at the moment but I'd be keen to have a look at your setup. Hopefully your new roof survives the next few days.
Over here !
