I have been working my way up to an obs build for a long time, the final intent being four piers. I have had a lonely pier for about 2 years and a hole next to it waiting for concrete for over a year (it filled with water before I could do the pour and I have been stupidly busy since) I recently managed to pump it and dry it and wrangle time to get the concrete poured and since then we have had nearly 200mm of rain so good timing on my part. Pictured here (the far one) with the new pier dummied up, waiting until this weekend for the concrete to cure some more before I drill it and chemset in the bolts.
I am actually just thinking now that I may build a separate shed as a warm room as it would make the ROR smaller and simpler (And the roof lighter) and in the case of the warm room/shed, probably get it under a size that requires a building permit in our council area. It would be nice to have somewhere secure and dry to store the gear that was more or less right at the piers.
Edited to add, yes, the pier blocks are not aligned. The first (Closest) one went in at a time when I was thinking I would build the ROR aligned with that block (Not quite running north/south) but since then I have decided to align the remaining blocks true north/south and the ROR the same way. I plan to hide my sin under a floor!
Last edited by The_bluester; 04-07-2023 at 07:24 PM.
In my view you absolutely need a separate room ...you can keep it warm..or cool..you can have lights on, you don't have to worry about light from computers..you can even have a tea and coffee table...a small bed..heck you could live in it...and if you need to work on gear you can do that in your separate shed to a large degree... I set up my observatory with a desk but in reality I can not use it when imaging and only in the day....it is best to leave your scopes in the dark and do "stuff" in your separate room..in fact build it first.
My separate shed is my van...today the ethernet cables arrived and soon I exlpect the box and conduit...then everything will be controlled from my van ...bed, tea coffee food you tube etc and a big monitor showing subs coming thru...good luck and please keep posting your progress.
Well it depends on what you want to use the observatory for, visual, traditional long sub imaging, or EAA imaging. For EAA it doesn't really matter. My computer and the image display screen are only 1.5 metre away from my pier. As long as light cannot get into the aperture of your scope you should be OK to have your office in the sane structure. An if it is an obsession you can always put up a dark room type curtsin. Don't over complicated the building is my advice. Have fun.
Long sub imaging in my case so a separate area is really required. I thought about adding the warm room to the main obs shed but then it starts to become a quite large shed with a large and heavy roof.
If I keep to a size that does not require a building permit (Less than 10 square meters in general in our shire) I can probably get a warm room/shed built to store the gear within meters of the piers, before the end of this winter. I just need to work out my main obs plans first so I don't put it in my own way!
I am looking at staging this and building a homebrew solution to cover the two piers with materials I have on hand, just to enable permanent setup of the gear while I design something to cover four piers.
Spend time sitting looking and thinking...sounds odd but often we are time poor and fail to actually sit and think...a chair and a cuppa is mandatory.
Good luck and remember work expands to occupy the time allocated to it...so set dead lines.
I keep a note book itemising jobs setting out the time it will take, the cost, the tools to have on site and if it can be done at night or day time...you can look at your notes while sitting and looking and so often you will notice a 20 minute job that can be done at night ( or in the rain for that matter) ...so many projects are made up of 20 minute jobs but we wait until we have a whole day set aside...if you have some spare time look at the book..if you have spare cask look at the book...with the book you can focus immediately to use spare cash or time..or even to move materials and tools on site.
Actually, somewhere to sit and think is one of the purposes of the warm room. I may even move my home office out there. I do plan to insulate it and line it nicely and I have some good carpet tiles to cover the floor. if I move the home office out there I will probably put in a split system aircon so it would be properly warm mid winter.
You are right about the job expanding to fill the time available. I have a couple of projects like that, the hole full of water for the pier block was just one of them.
There is that too, but when my astro buddy is here, coming inside at midnight for a whiskey and setting the dogs barking is unpopular. Best to give us somewhere warm to have a sip and chat. If I can wrangle enough size I might even be able to put a bed out there for if I really get myself in strife.
Slow progress, but progress. The second pier is now bolted down and the pier plate aligned and bolted on, just in time to miss the couple of clear nights we just had. I aligned the plate by the expedient of putting the mount on it, centring the mount azimuth adjustment and then using the inbuilt polar camera to line up the plate to true south so I could mark the holes to drill them.
Hi Paul. How deep did you have to dig for the pier foundations? I’m thinking of constructing a pier and am just getting some ideas on what how to do it at this stage. They look really wide. Is that normal?
I have probably gone to massive overkill so I might let others pipe up with any advice they have. The old advice used to be a cubic meter of concrete to ensure stability and lack of vibration, so I went with that for the two bigger scopes (A 10"F4 Newt and a friends longish refractor) though the second hole got wet and started to have the sides come in so it was more like 1.2M of concrete as paying for some extra was easier than trying to form up a box around a meter and then backfill and compact the rest.
I chose not to then use Sonotube extension to form the concrete up to the pier plate, I prefer the flexibility of being able to unbolt the pier and put on a different height or design if I want to so I stayed with a flat top and used Chemset to fix bolts in place.
I plan two more piers for smaller scopes (Shorty refractors both) so I will probably cut it to a smaller size like 1000X1000 by 600 deep for those, to get stability that would probably be good enough for the big scopes anyway, but certainly good for a 380mmFL refractor.
I will say that the big lump of concrete actually feels noticeably "Dead" to walk on, and you can jump up and down on it while guiding without seeing any noticeable effect.
Paul I think folk get carried away ..I know I have but when you think about it these days we use relatively short exposures and can polar align in a matter of minutes...
My system has 30 bags of redimix and 20 long star pickets and 10 short ones most of which are Frankie piled well past the concrete blob..no form work as it ain't going anywhere...and the ground is not flash with no bed rock that I could find...I do think the chances of movement are slim in the short term..long term does it matter when we do short exposures these days and we can polar align before each session in ten minutes...I do think Frankie piling is the key ..just imagine trying to move a blob a concrete made up of 100 bags of concrete with four feet of star pickets bristling out of it say 80 to 100...I shudder to think when some poor devil tries to pull it all up at some distant point in the future..because I ended up with four set ups..two coming up in a single pier and two each with three piers to take tripods ( eq8 and EQ 5 each have the same set up) these all ended up joining up concrete wise underneath with so many star pickets Frankie piled ..just imagine it if you could turn that upside down and lay it in the paddock...probably 80 to 100 star pickets sticking up...
Further unless you get a mount that costs more than your car block movement will not be a worry.
In my case I am still doing 5 and 10 minute exposures, and at least for now, up to 15 minutes on the second rig (The refractor has a CCD camera on it) so stability counts for us.
That said, aside from the cost of the concrete, digging the hole is not too bad, I hire an excavator now and again for works around the place and this hole was dug last time I did that. Next time will be the final pair of holes. They are pretty much dug already as I dug two and then as I was aiming for 1M deep and couldn't get it, so I filled in again and moved to where the current #2 is. If I go with 5 or 600 deep I can dig them out again pretty quickly. The rest of the day's machine hire can go to a trench for power and data out there.
The concreting is the easiest bit of it, a quick light reo cage welded up and spiked into the ground then the pour (I just get a mini mix in) and then making use of my meagre concreting skills to make it look acceptable.
15 minute subs are still comparatively short exposures to what people had to do with film back in the day...
Remember, subs... as in. Sub - exposure... when that wasn't possible, when you wanted to go 3hrs deep, you were literally firing a single 3 hour exposure, with your eye glued to the guide scope eyepiece, manually correcting dec drift.
I would say that for most modest setups, a 60x60x60 block of concrete would be more than sufficient, especially if like Alex, you dug the hole then rammed in a number of star pickets on various angles to bite into the surrounding earth...
Not to say going 1m³ is bad, on the contrary, it's amazing! But unless you've got a 16" scope with a few thousand mm focal length and running 20 minute subs with sub-arc-sec/pixel resolution and the seeing to match, it may be overkill.
Remember, concrete
, if properly composed at time of production, weighs between 2.3 and 2.4 metric tons per m³... that is quite a lot of balast for less than 50kg of mount and scope.
