Pier + "Astro Shed"

[Shibby]

Hi all,

I've taken a pretty long break from the hobby for various reasons, including moving house. But now that's over I'm ready to get going again and, after a bit of hard work, have been given permission to install a pier + astro shed into our new garden!

I've not done much like this before and would like to avoid any pitfalls (surely vital when digging holes!) So I would really appreciate a sanity check from the knowledgeable folk here before I start purchasing supplies and preparing.

My plan is to have an outdoor pier (I prefer to be under the stars when observing) and a warm room / astro shed for housing myself and the laptop when imaging. The pier will be surrounded by decking so I can comfortably walk around it at night.

Attached is a rather crude diagram (apologies!)

My thoughts are:

• 0.5 x 0.5 x 0.5 concrete-filled hole to affix the pier to
• Purchase the pier. I'm looking at this one: Pier
• A single sub-frame under the decking and shed, resting on cement pads + weed barrier and gravel
• An 8ft x 6ft shed like this one: Heavy Duty Shed
• Mains + Ethernet running from house
• 12v power + other cables running from shed to pier

Questions:

• Is the pier base large enough? Could it be smaller? (I plan to use ready mixed concrete by hand).
• The 0.5 x 0.5 x 0.5 hole should require about 14 bags of 20kg ready-mixed concrete - please sanity check!
• How important is the weather for curing?
• Do I need to limit the length of the 12v power cables?
• Will 2m enough space to walk around the scope?
• The concrete pads for the subframe - I read a guide that suggests filling holes to just above ground level, then level them all with a spirit How do I achieve this? (Can I rely on the strength of the damp concrete?)
• Does a mount such as the Vixen GP / EQ6 mount directly to the pier I'm looking at or do I need an adaptor?
• Anything major I haven't considered?

Many thanks,

[carastro]

A great step forward, but seems to me a lot of work and expense to leave the Pier and kit outside, especially if you are an imager when you might want to leave everything attached for a 2nd night's imaging.  Even if you are planning on leaving the kit up overnight you will have to do a lot of covering and/or removing of cables before you can leave the said kit which will be a real bind in the early hours as I know from when I image at Astro camps.  

Obviously it is your choice, but I would have gone for a ROR with warm room.  

However back to some of your questions.  What scale are you measuring  0.5 x 0.5 x 0.5 --- Metres?  I was told for my Skyshed pier (which has an NEQ6 on top, 2' x 2' x 3' deep.  You say you are putting decking around the pier, I am sure you will know to leave a small gap between the decking and pier to avoid vibration.  You will also need some fool proof method of making sure you don't trip over the cables running into the warm room.  

You will need a pier adapter for your NEQ6.

Check on the pier you have chosen to see whether it needs to be polar aligned on installation as doing it after you have cemented it in will be difficult/impossible.  I say check as there are some mounts that have rotation of the top plates that renders this unnecessary.

Can't answer any other questions.

Carole 

 

[Carbon Brush]

My first comment is on cabling.

For mains from the house, you need either armoured cable, so you can't put a spade through it, or a good quality cable duct/trunking.
don't forget the RDC (residual current device), also known as an 'earth leakage breaker'.
If you plug into an existing 13A socket, you avoid the electricial approvals headaches. Provided you are confident of your work.

When running 12V power from shed to pier, use heavy cables. You are going to need to run motor, dew heaters and goodness knows what else.
Flexible stranded wires are good and easy to work with. Go to a car accessory shop that specialises in loud audio. They need heavy cables.
Alternatively a few metres of twin and earth mains cable is an easy low cost method. Minimum 2.5mmsq (ring main) or even 6mmsq (cooker). Though not so flexible.
At each end terminate into a box with large and good quality terminals. Not nylon 'chocolate strip'.
Why not throw a few extra low power/signal cables in there?
A good quality USB lead. Some 4 core phone/alarm cable for unforseen additions.
After all this, leave a piece of strong nylon cord in there to pull through anything else you haven't thouht of.

Cable is cheap and can make the installation future proof.

Finally on cable. Bury round drainpipe as a shed to pier cable duct. If you leave lots of space in the duct, you can add or replace cables as required.

Now the pier. If you want a metal pier, why not run up a crude sketch and present it to a local fabricator? Use stainless steel so you can forget painting.
I have a stainless steel pier made by a fabricator that is sitting around unused. It is heavy enough for your setup. But I had other ideas.

My pier is concrete. Simply an extension of the underground bit.
I scrounged a length of round (galvanised steel) ventilation duct.
When the concrete got up to ground level, I planted the duct on top, then started filling the duct. Obviously continually checking for vertical as I worked.
At the pier top, I have a paving slabthat I had made round. then drilled 8 holes through and fixed stainless steel studs about 20cm into the wet concrete and 10cm above the slab.
Walk away for a few days until the concrete cures and you have a very solid pier that doesn't ring like some metal piers.

As I wanted flexiblity on mount type, I took an old car brake disc, drilled 8 holes to line up with the protruding studs and fastened the mount to the centre hole, as if it was on a tripod.
The brake disc is actually the most flexible part of the assembly. But it came in really handy when playing around with different mounts.

Hope this helps, David.

 

 

[Owmuchonomy]

Like Carol says why not just have a ROR. I see no advantage in having the pier separated from the facility. It's not difficult to do and there is plenty of support and advice on this forum. You will get better weather protection and security for your mount.  The pier looks a bit flimsy for me especially with the three gangly bolts holding up top plate. I am being slightly hypocritical here as I have the Altair pier which also has bolts, four of them but they are much more substantial than those in your choice. If I was starting again I would diy build the pier.  Regarding your concrete block foundation then I would advise at least 700x700x700 and it should be isolated from the pit you dig and the floor above.

[Shibby]

Thanks very much for the responses, I appreciate it.

I will reconsider the observatory approach with ROR, however I'm still not totally convinced just yet! The reasons I opted for an outdoor pier initially:

• It needs to be quite central in the lawn, because of those trees
• ROR observatories always look complicated to me. This feels much more simple for someone of my abilities!
• I currently use a heavy-duty cover over the tripod/mount without any issues so far
• I also enjoy observing, and not sure I want to do so from a box

BUT, I do appreciate the negatives, too:

• Can't leave scope attached
• Better weather-proofing (as Chris suggests)
• Better security (as Chris suggests) although our garden is odd in that there's no rear access!

1 hour ago, Carbon Brush said:

My first comment is on cabling.

When running 12V power from shed to pier, use heavy cables. You are going to need to run motor, dew heaters and goodness knows what else.
Flexible stranded wires are good and easy to work with. Go to a car accessory shop that specialises in loud audio. They need heavy cables.
Alternatively a few metres of twin and earth mains cable is an easy low cost method. Minimum 2.5mmsq (ring main) or even 6mmsq (cooker). Though not so flexible.
At each end terminate into a box with large and good quality terminals. Not nylon 'chocolate strip'.
Why not throw a few extra low power/signal cables in there?
A good quality USB lead. Some 4 core phone/alarm cable for unforseen additions.
After all this, leave a piece of strong nylon cord in there to pull through anything else you haven't thouht of.

Now the pier. If you want a metal pier, why not run up a crude sketch and present it to a local fabricator? Use stainless steel so you can forget painting.
I have a stainless steel pier made by a fabricator that is sitting around unused. It is heavy enough for your setup. But I had other ideas.

 

Sage advice on cabling - thank you   So... you don't have any current plans for that pier you have...??

1 hour ago, Owmuchonomy said:

Like Carol says why not just have a ROR. I see no advantage in having the pier separated from the facility. It's not difficult to do and there is plenty of support and advice on this forum. You will get better weather protection and security for your mount.  The pier looks a bit flimsy for me especially with the three gangly bolts holding up top plate. I am being slightly hypocritical here as I have the Altair pier which also has bolts, four of them but they are much more substantial than those in your choice. If I was starting again I would diy build the pier.  Regarding your concrete block foundation then I would advise at least 700x700x700 and it should be isolated from the pit you dig and the floor above.

Damn, that triples the amount of concrete I'll need! I'll admit, the Altair one looks far sturdier.

[Owmuchonomy]

If you go with your design and you think you will never wander around your pier whilst you are imaging then maybe you could get away with less. In fact, some folks on here mount their pier on a patio slab only in full knowledge it won't get disturbed.

[mountainmadman]

Just a potential word of caution on the decking idea...

I put decking down in the back garden a couple of years ago.  Now, if its wet or remotely frosty, it gets REALLY slippery.  I've nearly gone cartwheeling off the side a few times.  I know you can get non-slip boards which have kind of a sandy/gritty textured stripes along their length.  Possibly worth considering looking at those if you pursue the decking plan.

Good luck with whatever build method you choose.  I look forward to reading up about it!

Cheers.

Tony

[michael8554]

Hi Lewis

The really huge advantage of a permanent pier is to leave everything mounted and PA'd for DSO imaging. 

If you're only imaging planetary then perfect PA isn't necessary, so if  you're taking the ota in every night then you might as well leave it on the tripod and slide the whole thing into the warm room - no messing with big holes and concrete.

Aesthetically you can get summer houses with twin half-glazed doors that might appeal to her indoors.

Underground ducting needs to have "slow" ie large radius bends or plugs will get stuck. 

inside the duct leave thin nylon string at least twice a long as the duct, so that you can install or remove cables from either end.

Michael

[DaveS]

I too would avoid this "rat-box" pier, those long bolts are an invitation to vibration. You do *not* have to level the pier, as PA will take care of any out of level effect. I have a Pulsar "Rigel" pier with no top bolts, though mine does have an "owl nest" hole, which I've just found useful for mounting my dew controller.

The pier in my conservatory before being bolted down

[Carbon Brush]

Hi Lewis.

You are getting lots of good advice from everyone. On the ROR idea - give it some thought.

My obsy has the appearance of a garden shed with a pergola alongside to hold the roof when in use. So it is acceptable in a garden.
I had been told that the idea of a 'bottle recycling container' in the garden was not really acceptable.

Why ROR? When you finish a session. Whether it be bedtime, too cold, or cloudy, the ROR is very quick to abandon.
I just park the scope, slide the roof on and everything is closed up.
Next time out, slide back the roof, tell the mount to go and you are back where you started.
No algnment, no cables to connect, etc.

If you are really lazy (like me) then you can motor drive the roof using an auto garage door mechanism!

I went over the top on pier foundation. Well over half a cubic metre of concrete as a not very rectangular lump.
But concrete is cheap and in my view, if you are not sure, put in more than you need.

Rather than using ready mix bags, I bought the materials from a local builders merchant. When you calculate the approximate volume of the job, they will advise how many tons(?) of material you need.
By using a portable dement mixer, you can shift a lot of cement without too much effort. I found someone with a mixer who was happy to mix and pour for a few quid.

Session 1 was pouring for the pier. Then a few days after, pouring for the shed base.

Did I go over the top on the pier? Perhaps not.
At the design stage and while building, I was using an EQ5 & 8" newt. But had a bit of an idea I might get something a bit bigger in a few years.
Then the Alter D6 with Intes Micro MN78 came up 2nd hand at a good pricce.
The D6 mount is around 35Kg. The scope comes in around 20Kg, depending on add-ons.
Definietly not a package for a minimally built pier.

The only downside of the ROR is that you cannot use an 'off the shelf' shed.
Invariably sheds rely on the roof for rigidity. So you end up with additional timber in the walls.
The standard shed roof stays flat because it is fully supported on 4 sides. So work is needed here.
The door only needs to be large enough to get you in/out. You don't need to fit wide/tall items. Reducing door size helps with strength and security.
There is a lot elsewhere on SGL about shed building.

I would recommend using butyl rubber pond liner for any shed roof, rather than ordinary felt.
It remains flexible and waterproof for years (9 and still going strong for mine) and weighs less than decent roof felt.

 

Hope this helps, David.

 

 

[Shibby]

Thanks again for all the useful comments! OK, OK, I think you've all convinced me I've started planning an observatory. Although I may be limiting my sky a little bit more, it'll be worth it. The improved appearance will definitely please my wife too! Perhaps I'll get the large tree trimmed back anyhow. I've read most of the great threads in this forum over the years so have some idea of what's possible.

@michael8554 : Thanks, I'll make sure I use nice, rounded drain-pipe corners and leave some extra string for pulling new cables through.

@DaveS : That's a lovely looking pier, which I'll definitely consider. So long as I'm within a few degrees of north with the alignment I shouldn't have any issues. Quotes from fabricators seem to be several hundred pounds, so I'm still thinking of buying a ready-to-go one like this.

@Carbon Brush : My average setup time is currently about an hour so I can really appreciate the advantages of the ROR. I've been considering cannibalising the 12'x8' version of this sturdy-looking shed. With the 28mm walls and its interlocking boards, do you think it'll be sturdy enough with half the roof made convertable? I can always re-inforce where needs be.

I'm still in the brainstorming stage of things of course, but am wondering whether I can engineer the shed so that the right-hand half of the roof can slide back over the left-hand side. I don't really have the space for a pergola. If not, I may think about a hinged roof instead.

I've also been convinced to use more concrete, so I'll likely hire a cement mixer when the time comes! I wonder, cosidering I'll have a mixer, will it be easier to just concrete the whole area rather than trying to level lots of pads for the shed foundation?

[Shibby]

1 hour ago, Shibby said:

I wonder, cosidering I'll have a mixer, will it be easier to just concrete the whole area rather than trying to level lots of pads for the shed foundation?

Forget this bit - I've just done some calculations and find that 3" depth would amount to 1.5 tonnes!

[Davey-T]

Quote:

The concrete pads for the subframe - I read a guide that suggests filling holes to just above ground level, then level them all with a spirit How do I achieve this? (Can I rely on the strength of the damp concrete?)

Buy some 18mm sheet material, whatever is cheapest, and some 2"X 1" timber again whatever is cheapest, and make up some shuttering for the pads, level them using a level and long straight edge that covers at least 3 pads, then fill with concrete and scrape off level.

Cover tops with some damp proof membrane and treat timber well where it contacts the pads even if it's already pressure treated, which it needs to be.

Dave

[Shibby]

This is just a very rough idea, but I'm thinking about something like this (see attached). I could cut a hole in the roof (rather than cutting the roof in half) thus maintaining some of the structural integrity. Then, add a sliding section that will slide back over the warm room. Adding the rails to the top might be simpler but they'd just be exposed to the elements.

Any thought on this?

2 hours ago, Davey-T said:

Buy some 18mm sheet material, whatever is cheapest, and some 2"X 1" timber again whatever is cheapest, and make up some shuttering for the pads, level them using a level and long straight edge that covers at least 3 pads, then fill with concrete and scrape off level.

Cover tops with some damp proof membrane and treat timber well where it contacts the pads even if it's already pressure treated, which it needs to be.

Thanks, this makes more sense now! Can I still cut away the shuttering afterwards? Reason I ask is that I understand the concrete might sink a bit when setting.

[Davey-T]

1 minute ago, Shibby said:

This is just a very rough idea, but I'm thinking about something like this (see attached). I could cut a hole in the roof (rather than cutting the roof in half) thus maintaining some of the structural integrity. Then, add a sliding section that will slide back over the warm room. Adding the rails to the top might be simpler but they'd just be exposed to the elements.

Any thought on this?

Thanks, this makes more sense now! Can I still cut away the shuttering afterwards? Reason I ask is that I understand the concrete might sink a bit when setting.

 

Yes, when it's dried a bit you can knock the shuttering off.

Dave

[Skipper Billy]

There is also the 'clamshell' option

https://sites.google.com/view/astro-imaging/observatory?authuser=0

https://sites.google.com/view/astro-imaging/equipment?authuser=0

 

[Carbon Brush]

Think about the tracks and wheels. In your drawing you show round profile wheels running in rectangular section tracks.

For my roof, I added a semicircular plastic track to keep the wheels aligned and ensure the roof slid correctly.
Being miserly, I used plastic waste pipe fed through a band saw. Then a few countersunk screws to hold the plastic track to the wood.

A weakness of this design is that in cold weather, the exposed part of the track gets iced up after snow melting.
So when you get a clear sky after (the wrong sort of) snow, you can't open the roof!
Fortunately this has not happened often enough to force me to spend on, or think about, a solution.

David.

[Shibby]

3 hours ago, Carbon Brush said:

Think about the tracks and wheels. In your drawing you show round profile wheels running in rectangular section tracks.

I'm actually planning to use steel V-shaped wheels and matching tracks, as recommended by a few members here. I admit the sketch is very unclear! (was a rough idea only).

I'm still doing a lot of umming and ahhing over the specific design, though. I also can't decide on the shed foundations; whether to scale up the concrete, pouring several pads, or to just go for paving slabs. If I go for slabs, I think I can get away without having to construct a proper shed base... can I?

One more challenging part of the design is how to prevent water ingress at the highlighted area when the roof is closed. I've done another quick and dirty sketch of one idea - adding an upwards lip to the fixed roof and a downwards one to the sliding roof. Any suggestions how to improve this or comments on whether this would work?

Thanks very much.

[Star101]

As I am in the process of planning my ROR Shed too. I am posting this to keep track of your progress. 

I know nothing about shed building or pier construction for that matter. The interweb is my only source of learning

I have a 12"x 1cm steel disk and a 7' x 10" steel tube arriving today to be part of the Pier for my Mesu mount when it arrives next month. I have a designated patch in the garden to build my 10' x 8' ROR shed. 

I look forward to seeing how things progress.

[Shibby]

4 hours ago, Star101 said:

I know nothing about shed building or pier construction for that matter. The interweb is my only source of learning

You're not alone; I'm a complete novice at all this (apart from putting up a small, off-the-shelf shed once!)

I'm having serious doubts about my design idea... the roof panel is huge (2.4m long) and I'm not confident I can make the sides of the structure strong enough to support it. I'm sure someone could, but not me 

So I'm currently at the back-to-the-drawing-board stage. I'll post some other ideas here soon.

[Davey-T]

Have you considered making the roof from steel tube, this will mean it can be covered in lightweight sheets  rather than really heavy stuff and be easier to fit rollers to.

A roof constructed of strong enough timber tends to collapse under its own weight and will require some sort of maintenance .

Off the shelf sheds aren't really suitable as the roof is an integral part of their strength, you're better off making the whole thing from scratch.

Have you considered a plastic shed, these can be erected in a weekend by one person, no DIY skill required, they have a built in floor and can be stood on a square of paving slabs and converted to roll off at your leisure.

Dave

[Mick J]

Difficult to describe this roll off roof stuff, we have a section of flat roof with an upstand, top of upstand same height as opposite wall,  the rolling roof caps and rolls onto two 3x2 timbers infront of the obsy that look like a bit of garden framework. We do get a bit of water where the two roofs meet - mostly staining seen from inside, some wind blown and some water running along the tops of the 3x2 - these are over 5 meters and the 2.4 roof rolls well away.

The roof has to have some weight, I don't like the look of your sloping roof in the drawing above - I would expect some pull/movement downhill (but more wheels against wall?) - we have to make sure we move our roof carefully and not slightly out of true but it works well - don't get much use anyhow but that's.....

I made the roof to light and it now dipps in the center, no problem but always a puddle after rain. I have half a plan to add some metal across inside to push it back up, the roof of course was lifted in one piece onto the obsy. I do like to think I have some building skills - I have all the tools somewhere!!!

The obsy walls I made 3x2 again, ply or timber clad both sides, these don't move/wobble or twist, most sheds the fixed roof helps hold the shape and walls in place.

We had ready mix delivered for a 1m square hole - probably far to large but an easy calculation, ******'s dumped far to much in the road and left us with it! I would advise mixing yourself.     Hope this is helpful Lewis, good to see you back.

[Shibby]

4 hours ago, Davey-T said:

Have you considered making the roof from steel tube, this will mean it can be covered in lightweight sheets  rather than really heavy stuff and be easier to fit rollers to.

I have been looking at different materials, yeah. Have been considering corrugated sheets or polycarbonate, which I could spray. Quick thought - could the frame be made from aluminium tube? Is this strong enough in relation to timber, if using a lightweight sheet? I suspect not, but would be very easy to put together: http://www.aluminiumwarehouse.co.uk/EasyFix_Tube_Connectors/c180/index.html

[Shibby]

4 hours ago, Mick J said:

Difficult to describe this roll off roof stuff, we have a section of flat roof with an upstand, top of upstand same height as opposite wall,  the rolling roof caps and rolls onto two 3x2 timbers infront of the obsy that look like a bit of garden framework. We do get a bit of water where the two roofs meet - mostly staining seen from inside, some wind blown and some water running along the tops of the 3x2 - these are over 5 meters and the 2.4 roof rolls well away.

The roof has to have some weight, I don't like the look of your sloping roof in the drawing above - I would expect some pull/movement downhill (but more wheels against wall?) - we have to make sure we move our roof carefully and not slightly out of true but it works well - don't get much use anyhow but that's.....

I made the roof to light and it now dipps in the center, no problem but always a puddle after rain. I have half a plan to add some metal across inside to push it back up, the roof of course was lifted in one piece onto the obsy. I do like to think I have some building skills - I have all the tools somewhere!!!

The obsy walls I made 3x2 again, ply or timber clad both sides, these don't move/wobble or twist, most sheds the fixed roof helps hold the shape and walls in place.

We had ready mix delivered for a 1m square hole - probably far to large but an easy calculation, ******'s dumped far to much in the road and left us with it! I would advise mixing yourself.     Hope this is helpful Lewis, good to see you back.

Thanks for sharing your experience! It's a whole can of worms, this roll-off thing. I'm making it even more complicated by opting for roll-over, but I'm determined to make it work one way or another. Yeah, I'm going to have to add some sort of guide rails to keep the roof true when moving.

[Davey-T]

32 minutes ago, Shibby said:

I have been looking at different materials, yeah. Have been considering corrugated sheets or polycarbonate, which I could spray. Quick thought - could the frame be made from aluminium tube? Is this strong enough in relation to timber, if using a lightweight sheet? I suspect not, but would be very easy to put together: http://www.aluminiumwarehouse.co.uk/EasyFix_Tube_Connectors/c180/index.html

You can get the same thing with steel tube, the joiners are a bit limited as you may need to introduce a slope somewhere.

Dave