Elevated tower / platform for astrophotography

[8324689]

Hi there, has anyone built an obsy on a purpose-built elevated structure? I have trees around me and need the height. I would hope not to break the bank in doing so but making something I can climb up to or use stairs to get above viewing obstructions. This would be for astrophotography, so needs absolute sturdiness......  RSJs/ concrete tower??  budget is an issue though..... 

 

My brother has a wood laser cutter so could make the DIY dome but this is more about the structure to house the dome..... HEQ5/C8

 

Thanks!

Edited October 15, 2023 by 8324689

[saac]

You could drop a line to @Rusted although his amazing observatory is a little more complex than an elevated platform I'm sure he would have a wealth of experience on the do's and don'ts. 

Jim 

Edited October 15, 2023 by saac

[Peter Drew]

How high?

[8324689]

Just now, Peter Drew said:

How high?

i would imagine 8ft or 10ft?

[iapa]

I understand that, due to a bereavement, Rusted is no longer progressing with astrophotography.

It may be polite to allow some time before contact?

[8324689]

1 minute ago, iapa said:

I understand that, due to a bereavement, Rusted is no longer progressing with astrophotography.

It may be polite to allow some time before contact?

100%, thanks for letting me know

[Rusted]

Thank you for your empathy but I am happy to advise if I can.

Trees were my problem too. The problem with trees is that they continue to grow.
Unless you are the owner of the trees and the land on which they stand you are powerless.
Even then you may be subject to tree preservations orders.
Assume that neighbours will hate your "monstrosity." I was lucky and live rural detached.

My raised observatory was designed to be dismantled if required. NO NAILS!

My method of safely gaining height for my home made 3m/10' dome was the use of 4x4 [10x10cm] sawn timber uprights.
These were mounted vertically, on the adjustable, galvanised brackets of concrete, carport anchors.

I made an octagon with an outside, fenced balcony. For safe access during outside dome maintenance.
A mitre/circular saw was used to accurately cut spacers in 2x4 [50x100 mm] and 2x 6 [50x150mm] timber for reinforcing rings.
Floor joists were 2x10, 2x8 and 2x6. As recommended by skilled US carpenters on another astro forum.
From which I was subsequently banned.

I used lots of 'Climate' and galvanized coach bolts. Torx wood screws too. Using high quality driver bits.
I should have had a rechargeable screwdriver but used an ordinary rechargeable DeWalt drill instead.
Which lacked the guts to drive 100 and 150mm screws. So I needed to use the Drilling mode.
Which caused repeated wrist injury due to twisting without a safety clutch.

The timber skeleton was then clad in 12mm decoratively grooved, exterior plywood.
Using countless screws to obtain a stressed skin design.

I bought an aluminium, warehouse stepladder for access to the observatory floor.
One of my wiser decisions. Never accept a normal ladder as a means to a raised platform or observatory.
You need flat treads for balance and stability when climbing with delicate, expensive, large and heavy equipment.
Shelter the stepladder, if you can, to avoid ice and snow build up.

My 14' pier was a simple pyramid of sawn 4x4s. Partially clad in 18mm exterior Baltic birch plywood.
Standing on four more carport anchors at maximum radius to fit inside the building.
I climb inside the pier via  the stepladder for access to the obs. floor.

The floors were larch terrace boarding and hideously expensive.
I have tons of pictures but you'll find my entire build on my blog in my signature:
I worked entirely alone at the age of 70-ish in 2017/18.
My blog has dozens of posts illustrating progress.
The endless text describes my ideas and design decisions at great length.
The pics below show the completed skeleton. Then the observatory after a couple of years of weathering.

 

[bwj]

@Rusted , looks like a great observatory. I you look on Cloudy Nights, in their observatory forum, there are several examples of people who have built observatories on their garage, etc. The piers run down to the ground.,  some using concrete blocks, some pipe. Rusted's pier support would definitely be easier and cheaper.

[jjohnson3803]

I've have an ongoing interest in elevated obsy's even though my HOA forbids building any kind of outbuilding.  Personally, I'd look into a concrete block structure with a poured concrete observing deck.  There's a good example on CN of one that somebody built in Mexico.  Price could be an issue though.

Another option would be using a surplus 20-ft shipping container for the lower level.  I'm told the tops of containers are not designed to handle a lot of weight, so it would probably have to be reinforced with some kind of wood decking.  It's certainly feasible - I stayed overnight in a 40-foot AirBnB that had a rooftop deck.  There are many images on the Net.

I have no experience with a wooden structure aside from my back deck that is only a couple feet high and wobbles a good bit when I bounce my foot on it.  😜

Good luck!

 

Edited October 16, 2023 by jjohnson3803

[8324689]

12 hours ago, Rusted said:

Thank you for your empathy but I am happy to advise if I can.

Trees were my problem too. The problem with trees is that they continue to grow.
Unless you are the owner of the trees and the land on which they stand you are powerless.
Even then you may be subject to tree preservations orders.
Assume that neighbours will hate your "monstrosity." I was lucky and live rural detached.

My raised observatory was designed to be dismantled if required. NO NAILS!

My method of safely gaining height for my home made 3m/10' dome was the use of 4x4 [10x10cm] sawn timber uprights.
These were mounted vertically, on the adjustable, galvanised brackets of concrete, carport anchors.

I made an octagon with an outside, fenced balcony. For safe access during outside dome maintenance.
A mitre/circular saw was used to accurately cut spacers in 2x4 [50x100 mm] and 2x 6 [50x150mm] timber for reinforcing rings.
Floor joists were 2x10, 2x8 and 2x6. As recommended by skilled US carpenters on another astro forum.
From which I was subsequently banned.

I used lots of 'Climate' and galvanized coach bolts. Torx wood screws too. Using high quality driver bits.
I should have had a rechargeable screwdriver but used an ordinary rechargeable DeWalt drill instead.
Which lacked the guts to drive 100 and 150mm screws. So I needed to use the Drilling mode.
Which caused repeated wrist injury due to twisting without a safety clutch.

The timber skeleton was then clad in 12mm decoratively grooved, exterior plywood.
Using countless screws to obtain a stressed skin design.

I bought an aluminium, warehouse stepladder for access to the observatory floor.
One of my wiser decisions. Never accept a normal ladder as a means to a raised platform or observatory.
You need flat treads for balance and stability when climbing with delicate, expensive, large and heavy equipment.
Shelter the stepladder, if you can, to avoid ice and snow build up.

My 14' pier was a simple pyramid of sawn 4x4s. Partially clad in 18mm exterior Baltic birch plywood.
Standing on four more carport anchors at maximum radius to fit inside the building.
I climb inside the pier via  the stepladder for access to the obs. floor.

The floors were larch terrace boarding and hideously expensive.
I have tons of pictures but you'll find my entire build on my blog in my signature:
I worked entirely alone at the age of 70-ish in 2017/18.
My blog has dozens of posts illustrating progress.
The endless text describes my ideas and design decisions at great length.
The pics below show the completed skeleton. Then the observatory after a couple of years of weathering.

 

Stunning and inspiring!! 
thank you ! 

[8324689]

OK so after some inspiration from @Rusted what about a telegraph pole/tree trunk (my brother is a tree surgeon) 1/3rd submerged into the ground with concrete for complete steadiness and then my pier on top. Then a decking surrounding it that is decoupled and then one of those Keter-type sheds placed around/on top of the whole thing with a roll-off roof.

 

Once the decking is decoupled from the telegraph pole it shouldn't make a difference if I dance on it or not. 

[Steve Ward]

I used a 14' tall pier at my old address to get 365 days of solar imaging back in the day (2012-2015)

Simply a 100mm x 100mm timber post sat on the patio and braced against the brick wall , it was a bit of an adventure dragging the HEQ5 Pro and Tal100rs up a ladder but it  got me 311/365 so well worth the effort as most folk give up around this time of year. 

[Rusted]

A free standing post is very unlikely to be successful.
The taller it is and the higher the loading the lower the resonant frequency.
And, the longer it vibrates at the slightest touch. Because it has such dreadfully poor self-damping.

I tried a steel pole. Hopeless. A steel pole full of sand. Hopeless. A steel pole dull of concrete. Hopeless.
My pyramid of four timber posts uses geometry and the natural damping of timber. Common metals ring forever.
Every force applied at the top of a pyramid is resisted by the opposing legs.
The cladding stiffens it further. Though one has to be careful or its weight will form a vibrating plate!
I had to remove some cladding to damp the unintended resonance.

It still wasn't perfect. Despite having a couple of hundred kilos of my DIY equatorial mounting on top.
So I had to isolate the imaging desk entirely from the pier. As well as isolating the building from the pier of course.

My plan was to avoid leaving any trace of my observatory building if I moved or died.
I can dismantle the whole thing and leave only the gravel on the ground behind.
I shall probably do that next. Though I hope somebody will take away my 4.3m/14' GRP dome.
So I have more room to work. Though I have no plans to move away. Nor dying yet.

IF you are willing to cast a huge foundation block you could build a precast chimney block pier.
I wasn't willing to leave such a carbuncle for the next owners  It wouldn't be fair to them.
Cast your concrete with that firmly in mind.
My carport anchors, in sufficient numbers, will support a two story building. Or a tall pier.
I used eight on the original octagon. 14 anchors on the enlarged building.
Four more on the pier on the largest circle I could manage within the building.

 

[Rusted]

4 hours ago, bwj said:

@Rusted , looks like a great observatory. I you look on Cloudy Nights, in their observatory forum, there are several examples of people who have built observatories on their garage, etc. The piers run down to the ground.,  some using concrete blocks, some pipe. Rusted's pier support would definitely be easier and cheaper.

Thanks. After a long running thread on my observatory build, on C&N, they finally got rid of me.
Because I kept mentioning H-alpha telescope mods in answer to queries. Which were banned from discussion.
I was using a 6" f/8 modified PST myself at the time. You can blame Peter Drew for that. 😉
Fortunately H-alpha telescope mods are discussed at great length by some very clever people on SolarChat!! forum.
Where progress and understanding of the safety, limitations and advantages of modding continues to this day.

 

[bwj]

@Rusted, Sorry to hear about that.

Edited October 17, 2023 by bwj
spelling

[Peter Drew]

Disclaimer.  It was my fault that Rusted got into PST modding, not him being banned from a forum.   😀

[8324689]

Thanks for this and let me ask just for a final time. (Sorry if Im flogging a dead horse!)

 

Would not a wooden telegraph pole 1/3rd submerged and 2/3rds exposed in the earth with concrete not be solid??

just for a C8 and HEQ5 

thanks again 

 

 

Edited October 17, 2023 by 8324689

[Rusted]

1 hour ago, 8324689 said:

Thanks for this and let me ask just for a final time. (Sorry if I'm flogging a dead horse!)

Would not a wooden telegraph pole 1/3rd submerged and 2/3rds exposed in the earth with concrete not be solid??

just for a C8 and HEQ5 

thanks again 

 

Height to the top of the post?

 

Edited October 17, 2023 by Rusted

[Swoop1]

4 hours ago, 8324689 said:

Thanks for this and let me ask just for a final time. (Sorry if Im flogging a dead horse!)

 

Would not a wooden telegraph pole 1/3rd submerged and 2/3rds exposed in the earth with concrete not be solid??

just for a C8 and HEQ5 

thanks again 

 

 

I would say no. 

A telegraph pole erected by BT/ Electric companies still has a fair amount of movement (comparitively) so would not be stable enough as an imaging set up.

Using a tree trunk  salvaged by your brother will possibly suffer shrinkage/ twisting/ flexing as it cures.

[8324689]

Gah. Well back to the drawing board I suppose. Maybe a concrete block tower…. 

 

Rusteds solution is fantastic but perhaps too difficult for me. 

[Swoop1]

Don't completely discount a wooden pier for your rig- you just need to choose the right solution.

I looked at wooden piers when I set mine up. The twisting/ bending issue I pointed out above has been overcome by others.

The way to do this is to decide what profile pier you need for stability at the height you want. Then you construct a pier by joining together 4 length of timber in a battenburg pattern. Using 4 sections of timber helps to keep the pier in shape and straight.

Join them together with long coach bolts. 

See this thread from another forum- https://www.cloudynights.com/topic/397110-backyard-wood-pier/#entry5086111

I think a 12-16" a side pier should give you the stability you need.

Good luck!

[jjohnson3803]

Just for reference:

concrete-block-platform-observatory

 

[Mr H in Yorkshire]

@Swoop1 Completely agree, woodwork has be more manageable than concrete.  

@8324689 Your issue is not material, it's structure. As long as you make braced triangles wherever possible, even wooden poles would  do - but note the plural. 

[Rusted]

Short piers can get away with far more sloppy building skills than tall ones.

Remember that joists are laid on edge. They are also supported from both ends.
The stiffness rises as the cube of the timber's depth. Use depth, not width, in your designs.
Make everything multi-purpose in stiffening your structure. Turn depth at 90º between each member.
A four sided structure with [stressed skin] sheet covering becomes even stiffer.
 
The "four poster" wooden pier threw away enormous potential in bolting the posts tightly together.
Spacers would have increased the cross section, stiffness and spread the vibration modes.

Small spacers at the top and large spacers at the bottom would triangulate the structure.
Cover the newly tapered structure in plywood and you have a smarter design with far greater stiffness.
Such a design would have avoided the stresses of warping of the individual posts.

Use the carport anchors at ground level to support each post.
You gain fine control over levelling and have avoided the vast, ready-mix lorry leaving tracks across your lawn. 😉

 

[Mr H in Yorkshire]

@8324689 Don't be discouraged from a timber structure so quickly. Listen to Rusted's advice and use his design or very similar, it's the epitome of using structure to stiffen the overall construction even though the material is inherently flexible. Look on it as an opportunity to develop a new skill in woodworking, you don't even need to cut fancy joints, just flat overlaps of the bracing on the inside of the uprights, and plywood sheet on the outer faces. Use timber connectors* and bolts or screws if you are not concerned about re/moving it some time.  *Like washers but with sharp teeth that dig into the wood. You can do it all with hand tools, especially battery powered ones.

More complicated is a dome but you even dispense with that altogether and just use a simple box shape with a fold over roof.

You would be very proud if you manage it, I know I would.

Edited October 20, 2023 by Mr H in Yorkshire