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Newbie Observatory Build

Ian Thrax

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Let me just say that I have been on the site for a while, but this is my first thread.  So if this is the wrong place or I infringe any rules, codes of conduct, etc.  It was not my intention and would ask the moderators to let me know ASAP.

Part 1 the first attempt at a Roll on Roll off roof!

I got into the hobby about a year ago and soon decided that I needed an observatory getting old and setting up on cold nights isn’t a good mix. 

Whilst looking for ideas and other peoples common sense solutions I found SGL, loads of great ideas especially on this forum, so a big thank you to all of the people whose ideas I just straight up pinched or pinched and modified (eventually) to suit what I had to work with.

Made lots of mistakes along the way, plenty of rough carpentry, rougher electrics and terrible electronics.  So sorry if I trigger the OCD crowd, but this is what I did with what I had, warts and all.

 I hope that if someone else is thinking of doing an Obsy build but are being put off by their lack of experience, that this (tongue in cheek) thread, and I am sure the comments it will generate, may just give them an idea of what to do or not to do and show them that even a complete Newbie like me can come up with a rudimentary obsy set up that is good enough, for me, if no one else. 

Didn't take too many photos during the build so excuse any gaps in pictures!

What I started with.

4.32m x 3.24m Pent roof garden shed, full of garden stuff, bit damp, a bit leaky, but with light and electrics.

Never got a full shot of the interior but this will give you an idea.



First thing I decided was I needed a hand powered roll on roll off roof, wanted to keep it stealthy to fool the local villains, so no big framework with supports and guides for me, she who must be obeyed wouldn’t let me either!


So, I went with 1 leg and large castors on the bottom, so with the roof closed it wouldn’t encroach on the beloved’s domain.  I knew I would have to do something about the leverage on that or it would snap right off! So made a removable strut at about 45 degrees 1 mt long that went from roof to leg, sort of helped but was never going to be the solution!


However, I could see the sky, cloudy as usual but I had an indoor view of the heavens! 

No pictures of the roof roller system, but it was 50mm fixed castors attached to the roof, running in 50 mm wide steel channel attached to shed, the whole thing must way 300lbs if it’s an ounce lumpy, and stiff could it be any better!!

Well yes because one night that bloody leg snapped right off and left me standing there like Atlas, somehow with my life flashing before me I managed to get the roof pushed back far enough to be able to let go without it clobbering me, and thus was the first design flaw shown to me.

After much pleading, jewellery purchases and promises of future gifts, she who must be obeyed, leased me the patio that I had paid for, and gave planning permission, hoorah.


So, this is what I eventually ended up with, still hand operated, but with a lot less adrenalin involved which can only be good for my dicky ticker.

To be continued, if there is any interest and the moderators don’t kick me out?

Next instalment the eagle nebula also known as the creation of the pillar.

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Nice obsy. Thanks for sharing your experience - it is a challenge to try make the roof supports aesthetically pleasing, but your story shows their importance! 

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I can't speak on behalf of all the moderators but this one loves the post and what you are building.  I look forward to seeing more.

One suggestion - do you think your better half would be happy with future gifts of say ..... mounts, scopes, eyepieces etc?


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Thank you Mike, unfortunatetly she cottoned onto that one when I was buying her, dewalt and snapon tools🤣  Jean is a gem really and never gives me too much grief, just enough to keep me on my toes! 

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Ian, looks a good project, thank you for sharing.

The errors or design flaws made me smile, I would love a push off roof,
but the supports are an issue as very in view of the house.

How are you mounting your scope/s?
or is this a future posting??


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Believe me the supports are very in view of the house and were a little difficult to get through planning.  All will be revealed in future posts but I have a celestron AVX mount, remember I was totally new when I ordered my equipment, if I knew then what I know now, it would have been a Skywatcher NEQ6 with the eq cable.   Not the best mount out there, if you have plenty of budget go for it, but I think it would have been better for what I want to achieve. I work away a lot and desperately want to make this observaatory fully remote, difficult with  any celestron, as soon as you kill power you have to be there to press buttons when you turn it back on!!!

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Hi Ian,  nice work, I use a rope and pulleys to open  and close my roof. could you use a similar set up. Although i have a "warm" room at one end of obsy and the rope goes up the deviding wall. just a thought.  ??

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The Creation of The Pillar

Ok now I have a hole where the roof used to be, so I get a much better view of the clouds and the extra light allows a much better view of the floor of the shed, not good, do we go for a pier?

 I can fit a tripod in there no problem, but I am not a small chap and as I walk around the floorboards sag and creak alarmingly not a problem when I am getting the lawnmower out. But visions of my intended target wobbling around as I move and my mount working overtime as the guider tries to maintain track convince me, a pier it is.

I have never designed a pier before so back to SGL to see what others have done, great steel tubes with all manner of welded gussets bolted to huge concrete blocks. Automated ones that slide up and down at the press of a button like something from thunderbirds.  Superb though they are and excellent solutions I am sure, they are all beyond my meagre means and even lesser abilities.

Then I see a post where a chap used a tube and filled it with concrete creating a strong fixed pier.  I seem to hear my father’s voice saying “Keep It Simple Stupid”, and the decision is made concrete it is.

So now to tackle the floor, do I remove it lock stock and barrel and replace the whole thing?  Hell no I am cheap AND lazy so find the joists and cut a hole in the floor.


The ring you see next to the hole is a slice of the tube I intend to use to help me decide on the size of the hole.  250mm bore culvert piping, don’t get the field drain stuff, its full of holes to let water in, I’ll leave the rest for you to work out!  Once I have the hole cut, I cut additional timbers and framed the hole to help support the floor.

Next is excavation for the pier foundation.


Dug down about 2  1/2 feet, the hole was about 20” x 24” ish, I know people go bigger and deeper but any construction is only a s strong as the weakest point and when you see my solution for supporting the mounting plate, you will know why I wasn’t concerned about the concrete!

Then came the rebar and conduit for wiring


I also lined the top of the hole with some 4mm thick plastic sheet, this allowed me to raise the concrete level slightly above the floor and once removed it would leave separation between the shed and the pier.

The Tube, The Pour, and the Mounting Plate


I used four pieces of timber to hold and align the tube to pour the first 20 inches or so, then when the concrete was supporting the tube, back in with the plastic edging and on with the pour.


Now you can see why I wasn’t too bothered about a 2 1/2 foot foundation the studding is the weakest link.

Alas here another moment of realisation dawned, as I looked at my creation, feeling rather like Doctor Frankenstein must have felt.  I thought, why the hell didn’t you run the conduits up inside the tube, you tube! 

Initially I was disappointed with this, but having made multiple changes to cables, data lines and junction box locations, I realised that on the outside has definite advantages for flexibility.  So if you do something that isn’t quite right, don’t beat yourself up, if it works in the end its all good.

Obviously you need to set the support plate and studding (12mm Stainless Steel) while the concrete is still wet and preferably point it north.

Well that’s pretty much the pier construction done, topped off the tube a little over full to allow for settling/shrinkage, shouldn’t have bothered, it didn’t.

Next I manufactured a adaptor plate copying the dimensions from the top of my tripod.


This was installed and levelled off using an engineer’s spirit level


Time to install 12v PSU and some cables



You can just see 3 12v power sockets in front of the multi meter, the other cables are USB powered extension lead and Cat 5 ethernet cable.

Now I know it isn’t the prettiest and probably not the safest electrical installation either, but it works just fine and the wife hasn’t cashed in the insurance yet, so again, apologies to the OCD crowd if this is triggering you, but its just fine for me for now.  

Mounting and connecting scope to come.

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Thanks for the suggestion Andy, all suggestions and ideas are welcome, why reinvent the wheel, this part of the build happened at the back end of last year during my Covid vacation.  I have since pinched another great idea on here from another SGL member who was most helpful and will be given full credit later in the post, the roof now opens at the flick of a switch, if you can put up with my incompetence there will be pictures and explanations further down the line.👍

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Scope and Peripherals

On goes the mount andother bits.


Then the Scope and peripherals


So main items

William Optics Zenithstar 81 APO

William Optics Flattener Flat 6A

William Optics 50 Uniguide guide scope

ZWO ASI Air Pro connected via Cat 5 direct to home network.

ZWO Asi 294 MM Pro Cooled Main Camera

ZWO Asi 120mm Mini guide cam

ZWO 7 pos Filter Wheel 36mm

ZWO filters LRGB and HOS unmounted 36mm


Old laptop

Celestron AVX Mount

Red dot HAWKE rifle scope as a finder

4 Port USB 3.0 powered hub

The setup works well and once set Polar alignment is rock solid so all I have to do is roll off the roof, wake mount from hibernation, take picture with ASI Air Pro, plate solve and sync. 

Then its off into the house and run whatever sequence I chose from my main PC, the asi air app is made for android, not PC.  But I found an android emulator called BlueStacks, which allows me to run the app flawlessly on PC, another bit of software to start up but well worth it.  I also run BlueStacks on my observatory laptop and all works seamlessly with the ASI AIR Pro.

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Now for Part 2 Automating The Roof

Now never one to be happy with a simple solution, I started to wonder how to automate the roof, others had done it so why not. 

Well one good reason is an off the shelf solution isn’t cheap so back to SGL to go pinching again.

I found an excellent post from an SGL member who used a ford KA wiper motor with chains and sprockets to operate his roof with great success.  I contacted him via SGL and he was extremely helpful, I have sent him a message asking if I can mention him in this post, as it is he who deserves the credit for this idea, however he hasn’t replied yet so shall remain anonymous until I hear from him.

In his version the motor works on a 3 position switch and a motor controller, pos 1 Opening, Pos 0 Off, Pos 2 closing.  As I had already started to consider turning the observatory into a remote setup I thought I could modify his idea to allow remote opening.


As you can see from the above it is no longer simple, but not that bad!

The bottom pulley of the 3 is the windscreen motor, top 2 idlers, by reversing the motor you can open or close the roof and the 2 limit switches stop it in the right position, simples. 

Then I started to mess about with it, wanting to operate it remotely I got a 4 way 12v relay board that is Wi-Fi controlled, the relays work in parallel with the switch so I can have manual or auto from the black selector switch pos 1 auto, pos 0 off pos 2 manual. 

The peripherals are all powered from a laptop style 12v power supply, but the motor pulls 9 amps and the PSU is rated to 5 so I used a 12v battery in the system to supply the motor, this also connects to the peripherals, which gives me backup if the power goes off I lose the house Wi-Fi but I can still use the switch to open/close the roof.

The bright orange lump is a resistor and a buck converter, side by side, used to recharge the battery.  The 12v PSU is connected to the resistor to prevent the battery drawing more than 2 amps and the buck converter increases the voltage to about 14.7v to allow a full charge to the battery.  This means the battery is always topped up and ready to go.

There are other things going on as well, relays for roof locks and a position sensor so I cant operate the roof if the scope isn’t in the parked position, an essential precaution!


Once the roof is shut, I have 2 of these magnetic 300 kilo pull strength locks fitted at either end of the roof, opening the roof automatically cuts power to them allowing it to open.  When closing the roof, it hits the closed limit switch and powers the locks automatically clamping the roof shut. 

Please excuse the god-awful brackets!  I was never a carpenter so rough and ready there, but I was once a toolmaker, and would have sacked myself for those!  However, lack of material meant they had to do.


Here it is all tidied up behind an OSB panel with access hatch on, still a mess behind it, but hey, at least you can’t see it.

Now I would like to say all this went smoothly with no errors from me, alas we all know that isn’t true!  This is 12v stuff and is relatively safe to use, 240 to one side of the PSU so careful there though.  But as you need to reverse the polarity to the motor to change direction it is very easy to get a dead short causing, bangs, sparks, magic white smoke and sudden intestinal problems!  Several electronic components were harmed in the making of this system. 

Please be aware, if you do try and replicate this system 12v is unlikely to kill you by shock (not impossible) but could well cause a fire if cables short out and overheat! 

So all joking aside I do have an idea of what I am doing and have thoroughly tested the operation of the circuit with a fire extinguisher to hand, until I was satisfied that it was safe to close up and leave unattended.

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The magnetic locks are a really nice idea as a way to automatically add some significant hold-down force - that should help a lot against wind!

The whole setup looks great - what position sensing approach are you using to check for parked vs non-parked?

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Using 2 magnetic switches in series on RA and Dec axis of the mount, when the scope is parked safely, they are both closed and it gives a safe indication to the dragonfly, which will then allow the roof to be closed.  Seems to work well but may well look to upgrade to something more accurate later, but the switches are cheap and work really well so may not?

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Heading towards automation

I have now re-done the roof rails and rollers for V track and 80mm gate rollers, once I finally found F H Brundle and bought what I wanted in the first place.

I have also added a Lunatico Dragonfly, which has replaced the Wi-Fi relays, it allows much greater flexibility.  The 12V power supply has also gone onto the wall next to the dragonfly, housed in the junction box on the left with an IP camera for surveillance.


A Hitec Astro weather deluxe provides a safety monitor for weather and sky conditions. 


Next I sorted out connectivity and 5V power options The black box is an 8 way internet switch, the yellow box is a Wi-Fi repeater extender and lower black box is a USB, 12 hub charging board giving 5V at 2.1 amps so powers switch, Wi-Fi repeater and IP security camera.

You can’t see it in the photo but I also have a pass through powerline for internet from the house so no drop outs on Wi-Fi.


Using an old Lenovo laptop to control everything with NINA and AsiAir app installed, this laptop was tediously slow, so upgraded hard disk to SSD and put 8 gyg of ram in, vast difference.  Processor still slow but boots in 30 seconds and much quicker overall.


Decided to put a UPS in and hope to monitor power and internet VIA Ascom drivers so If I lose either Ascom will give an unsafe condition and NINA will park scope and close roof.  The UPS runs all peripherals, Laptop, Dragonfly, main 12V power supply to mount USB 5V supply, etc. 

Tested it and everything functions after power loss, roof has own battery supply to motor so no big drain, will last more than long enough to do what I want it to do.


Coat of paint on the inside.


Tidied up the outside a bit, lousy picture.


So nearly there, well nearly across the start line, have to find out how the bloody cameras work next, can’t even see where you put the film!

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Trying to get NINA working with everything but having a real mare.  First problem Hitec Astro is only 32 bit so won’t work with NINA 64 bit had to install 32 bit version, now works.  But whichever version I use NINA will run a sequence brilliantly without guiding, but as soon as I try to add guiding to the sequence, I get an error message saying it can’t download the images!!!!!!!!!  Really killing me so any advice greatly appreciated as NINA is key to getting everything working together.

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It all looks very impressive, Ian! There will be some great pictures to come from that setup once your guiding problem has been sorted.

Have you tried doing the guiding just using PhD2, bypassing NINA?

Good luck with it,


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Cheers Rolf, I thought about it and may well end up doing that but NINA reacquires and forces calibration after star lost or meridian flip so would be nice if I can get it working!!  

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