Mount Stu Observatory mkII

[powerlord]

Hi chaps, So coming up to a year with my plastic fantasic Correx obsy

 

And it's absolutely served it's purpose - getting me out there every single imaging night, weather proof, etc, etc. But it was never intended as a long term fixture - just for a year or so to check this is something I want to keep doing.

I think I'm ready to make something more permanent now. I've decided where it needs to go, and approx the size it needs to be to accomodate my 2 EQ6rs and allow for one of them to have my biggest scope on it (300pds) - around 7x10.. I think 6x8 might be enough, but need to do some more measuring.. 'course you don't get 7x10s in metal, so more like either 8x10 or 6x8.

I am swaying very much towards metal sheds - I like the look (in a black or grey will go with garden, I think making the roof retract will be easier as much lighter, and it has to be a 2 part split retract - as I don't want another 10 feet of my garden with posts and supports on it. So if its a 10x8, the 10 is along the edge of my fence/bounday, with the apex running perpedicular, so I have 2 x 5 feet bits of roof that can roll off to each side, and hopefully pivot down so hang vertically to each side - kinda like @Skipper Billy here :

but in metal

I also like working with metal more - have my own welding gear, etc - so modifying, adding, etc.

 

On the negative side of metal is condensation, but a good DPC on the concrete base, plus inner insulation (silver bubble type probably) will stop most of that I expect. Also, I suppose one might get away with a slab base for a wooden shed (other than for piers), whereas need concrete for metal ? I'm struggling to think of any other negatives though ?

Wood wise - much more expensive, a LOT heavier roof makes the design and construction of roof mechanism far more complex. But no condensation issues.

I'd like to check if I'm missing some angles ?

I already have one 120cm metal pier ready in the garage - with EQ6r mounted and min elevation (if fully rotated west/east - that adds another 35cm, and that seems file to clear the fence. Unfortunately shed is going to be higher than that - unnessessarily, but that can't really be helped. Other than saying if I custom build a wood one, I could make it lower, whereas custom building a metal shed is a LOT more tricky (cutting thing sheet metal, etc). I need to get another similar pier before the build, which will mean either sourcing the metal and cutting/welding myself, or getting a firm to do it I suppose.

I'd plan on automating the shed roof too - and again that is a lot easier if it weighs only a few kg vs .. I dunoo if wood- 100kg+ ? - for metal, a few basic stepper motors etc and I could have it all done.

However, build wise there are a lot more people using wood - and I'm not pig headed and stupid enought to not ask myself why that is ? have I missed something ? Or is it just that generally most people are happier working with wood ? I mean - do some searches here, or on internet and you find hardly ANY sliding/removable/hinged/{whatever keywords you can think} observatories that have been made from metal sheds.. and that does make me question myself a lot.

At the same time most folk though my correx observatory was a mad idea and it's been absolutely amazing to use. So let's just say, while not a contrarian, I don't have a problem walking my own way.

Ideally I'll like to plan it all over the next month or so, and start work in the new year - as it's going in a different place from the plastic fantasic obsy - I can keep imaging in there for now.

stu

Edited January 8, 2023 by powerlord

[Stuart1971]

Here is my flip top version…just 5 foot square, 20mm thick wood and holds a dual side by side rig on an EQ8 mount….cost was £450 all in…

https://youtu.be/6wH2FlGyobk

 

[powerlord]

47 minutes ago, Stuart1971 said:

Here is my flip top version…just 5 foot square, 20mm thick wood and holds a dual side by side rig on an EQ8 mount….cost was £450 all in…

https://youtu.be/6wH2FlGyobk

 

very neat job. concrete or slab base ? and how high is your pier ?

For me to get my two mounts setup though I'd need it to be a lot bigger. And I think that's where that method of flipping roof off might become an issue  - yours two roof sections are only 2.5 feet x 5 (12.5sq ft) . for an 8x10, they'd be 5 x 8 feet(40 sq ft) so nearly 4 times the area, and likely weight a lot more that 4 times, since they'd have to have extra re-enforcing for the wider span.

Can I ask why you made it so they flip out to only horizintal rather than just flipping them out the full 270 degrees to they lie vertically against the sides of the shed when open ? did you think it would be too much stress on the hinges or was their another reason ?

I did consider for the larger size, making they flip out in two 'folds' - i.e. one side would flip/fold back on itself 2 feet, then that bit flips back the other 2 feet. But then you have 2 joints in the roof that need to be waterproof (prob via a rubber flange) plus its less convienient and impossible to really automate.

cheers

stu

[Stuart1971]

41 minutes ago, powerlord said:

very neat job. concrete or slab base ? and how high is your pier ?

For me to get my two mounts setup though I'd need it to be a lot bigger. And I think that's where that method of flipping roof off might become an issue  - yours two roof sections are only 2.5 feet x 5 (12.5sq ft) . for an 8x10, they'd be 5 x 8 feet(40 sq ft) so nearly 4 times the area, and likely weight a lot more that 4 times, since they'd have to have extra re-enforcing for the wider span.

Can I ask why you made it so they flip out to only horizintal rather than just flipping them out the full 270 degrees to they lie vertically against the sides of the shed when open ? did you think it would be too much stress on the hinges or was their another reason ?

I did consider for the larger size, making they flip out in two 'folds' - i.e. one side would flip/fold back on itself 2 feet, then that bit flips back the other 2 feet. But then you have 2 joints in the roof that need to be waterproof (prob via a rubber flange) plus its less convienient and impossible to really automate.

cheers

stu

Thanks

the reason for the roof panels only opening to horizontal, was so we could still use the space either side, and not have to keep it perfectly clear so as to be able to accommodate the panels to open all the way, in some ways I wish they did open all the way, as after a nights imaging the panels can be covered in frost, which then does make them even heavier to shut, and then the frost can drip on kit, so have to put a loose cover over if they are frosted up, while the desiccant dehumidifier does it’s thing…

I used 5”  fire door hinges which are superb and very very heavy duty, so no worries there, I did start with 3 hinges on each side as in the video, but now have 5 on each side, and it’s much better…

If I have made the roof any bigger I would have used gas struts to aid with the opening and closing, which would allow for bigger roof panels, that was an option when I was going for a bigger shed, but the design changed to this smaller one, and so they were not needed…it’s perfect for my kit as did not need any room to sit and control, as my conservatory is just 6 feet away, which is where my PC is on my desk….👍🏻

[powerlord]

1 hour ago, Stuart1971 said:

Thanks

the reason for the roof panels only opening to horizontal, was so we could still use the space either side, and not have to keep it perfectly clear so as to be able to accommodate the panels to open all the way, in some ways I wish they did open all the way, as after a nights imaging the panels can be covered in frost, which then does make them even heavier to shut, and then the frost can drip on kit, so have to put a loose cover over if they are frosted up, while the desiccant dehumidifier does it’s thing…

I used 5”  fire door hinges which are superb and very very heavy duty, so no worries there, I did start with 3 hinges on each side as in the video, but now have 5 on each side, and it’s much better…

If I have made the roof any bigger I would have used gas struts to aid with the opening and closing, which would allow for bigger roof panels, that was an option when I was going for a bigger shed, but the design changed to this smaller one, and so they were not needed…it’s perfect for my kit as did not need any room to sit and control, as my conservatory is just 6 feet away, which is where my PC is on my desk….👍🏻

re: opening all the way - that was what I was thinking. just now, but plastic obsy roof sits upside down on grass at night, and is often covered in dew or now frost - and yeh  - also use a desiccant dehumidifier.

I'm 3d printing out some sheds now at 1:15 scale so I can see in 3d as it were what size fits everything, and how to do roof. 🙂

 

[Carbon Brush]

Wood vs metal. But there is more.

I didn't consider metal in 2007 when planning my build.
There were far less observatory examples on the web either as photos or videos.
There were few ready made metal sheds around as examples or starting points. Those I saw were very poor.
Plastic sheds at the time had 'Wendy House' all over them.
SWMBO did not think a bottle recycling bank (aka Pulsar dome) was acceptable on the garden.
So wood was the known material and readily available.
I am competent (well I think so) working both metal and wood.
My big departure from the norm was to use pond liner instead of roof felt. An excellent choice still sound in 2022.

If starting today, I would do quite a few things differently.
Partly due to my design mistakes and partly because the equipment used in the hobby has changed.
But on materials today. I think combining the best aspects of wood, metal and plastic in a bespoke construction is the way to go.

Not thought through but.....
A metal framed plastic roof will keep weight to a minimum and be low maintenance.
Wood sides mean it is easy to screw/glue brackets to hang things like eyepeices, dovetail bars, tripods, counterweights, etc.
Metal sides mean the thieves can't pry off a couple of planks to get in.
Plastic to the ground is ideal for keeping moisture at bay. But needs a hard (wood?) cover so a dropped tripod leg doesn't poke a hole.

Lots to think about. Looking forward to reading how you get on.

David.

[powerlord]

all good points. I was thinking of lining the inside with foil insulation. I don't really have much I want to store out there - most stuff will be in the house except maybe the 300PDS. As I have now, I'd probably just move my metal shelving unit to it - which is both a storage unit, and power source (it has custom build 5v/12v PSU and aviation sockets to connect the mounts with eveything they need.

I believe metal shed are really light - the actual sheet metal is very thin (0.3-0.5mm) so roof should weight nowt anyway. I will probably spray paint it white though as I learned with my plastic obsy - black roofs make it get very hot very quickly, even in the spring and with fans for ventilation. But you talking about plastic got me thinking rather than paint, it might be worth doing exactly same thing I did with plastic obsy  -added a layer of white correx on the roof - not only does this reflect the heat, but it's corrugated internal structure means it acts as  an insulator (from sun on summer, from frost in winter.

Floor wise, yes something over the concrete - though metal  sheds have a metal frame base that bolts to concrete, so easy to lay something like laminate over it and make it look nice ?

Security wise, I reckon there's maybe nowt much in it  - if someone wants it, they'll get in. I use wireless blink cameras just now for security and will continue to do so. I'll probably use an electric lock for the door, controlled by a wee esp32 I'll build so I don't need to faff with keys - I have an alexa dot in the obsy just now for similar reasons - it means I can control things by just asking it, rather than fannying around switching things. 'alexa turn dehumidifier on' 'alexa turn mount power off' 'alexa arm observatory' .

the only thing you have to ensure is for stuff like opening doors, you can't give it a pin, so you have to have a secret way of doing it. For example, to open by garage door (since there is also an alexa in the garage and you don't want someone just being able to shout 'alexa open garage door' at my garage door), I have it saying (words changed here of course) - 'ALEXA FISHY SQUIRREL PICKLED BEETROOT' - and voila garage door opens. 🙂

 

[aleixandrus]

On 13/12/2022 at 12:24, Stuart1971 said:

Here is my flip top version…just 5 foot square, 20mm thick wood

Hi! Very interesting topic. I don't want to divert the main discussion topic but...

- Size and roof opening system may condition the material. @Stuart1971, love you obsy! Do you feel 5 feet too narrow? What about wall height?

- Have you considered 'sandwitch panels' as this one? I don't know if this is the correct term in English but I'm considering this material for roof and walls as it is an all-in-one solution (wall structure, thermal and water insullation, decoration...). You only need a simple metal framing for the main structure.

[Carbon Brush]

On security. I won't give away any specifics or big secrets on open forum. But a few pointers.
My build predates the birth of Alexa and other voices in the cloud.

Ensure the strong points are not obvious from the outside. Don't give the villains any pointers on where to start.
For example the ordinary wooden door has standard shed door hinges. But inside there is a big metal bar.
If they think they are making progress, they continue. If they meet obstacles, they are more likely to move on.
Make opening (without alarm trigger) conditional on at least two interlocked strong parts moving. you soon get used to this.

I used an aftermarket car alarm. These being intended to work over a wide temperature range, and have a low power requirement from a 12V battery.
They will trigger (with or without delay) from simple switches. Like door unlocking, or opening, or roof sliding. Arm/disarm is by secure key fob device.
A wire in the (wood) shed side will break (triggering alarm) if someone tries to pry off a plank.
Use more than one alarm siren. Smashing off the obvious sounder is too easy. Make them loud.
If it is painful to stay in the shed, that is more important than waking all the street.
Make the inside is loud and bright on trigger. They won't stay!

 

[powerlord]

Here's my scale model 'Wendy observatory'.  1:15.

Scope is my biggest 300pds.

Shed is a 6x9 metal on on ebay.. I think this will work, but will need limit control for low east or west.

Everything to scale. Basic eq mount made, so I can move it around and check.

[adyj1]

[Fair disclosure: my DIY competence is inversely proportional to the unreasonably high ambition I have for my projects.]

I built a metal shed ROR obsy last year. Got an 8' x 4' from Amazon: Apex Roof Storage Shed (Grey, 8x4) ( in green). The 4' width was a limitation of space, but my 150PDS/EQ6 fits neatly. 

First warning: the metal is very thin and flimsy, with structural rigidity being provided by the roof pinning the walls together. Strengthening the roof is a double-edged sword - you want to try to keep the weight down, but need the roof to stay absolutely rigid for your motors and runners to work reliably. I used a not-excessive wooden frame and this added a fair bit of weight (which at least has the advantage of stability in windy conditions). I see you are planning use stepper motors, so you'll need to make sure they are man enough for the weight of your strengthened roof. Are you thinking of using the heavy-duty drawer runners, or v-groove wheels? I used a gate motor for automation (a la astrobloke) but then again my roof is all in one piece. 

The sliding doors on this type of shed are ultra-flimsy. I've had to move the handles up the doors so they are closer to the 'hanging runners'  at the top to open them smoothly. I've fitted a locking hasp to the outside for security, but this is more to put off the casual thief than a determined burglar. I'm expect the visible CCTV cameras covering the garden, shed and back gate are the biggest deterrent. I suspect a rambo-style hunting knife would open up the shed door (or walls) like they were nothing more than sturdy parchment...  😞

Mind you, there's a fair chance any thief would knock themselves out on the beams that run out at about 5' high either side of the shed door (for the roof runners) - I know I've banged my head on them more times than I count - and I'm the eejit that put them there 🤣

HTH

Ady

[Stuart1971]

1 hour ago, aleixandrus said:

Hi! Very interesting topic. I don't want to divert the main discussion topic but...

- Size and roof opening system may condition the material. @Stuart1971, love you obsy! Do you feel 5 feet too narrow? What about wall height?

- Have you considered 'sandwitch panels' as this one? I don't know if this is the correct term in English but I'm considering this material for roof and walls as it is an all-in-one solution (wall structure, thermal and water insullation, decoration...). You only need a simple metal framing for the main structure.

Thanks…

It’s plenty of room, for my set up, and to get round it if needed, check out my other video on the YT Chanel, which is a complete walkthrough of my rig, will give more of an idea of the size, and you will see it’s fine for me…As for wall height, it is the native height that the shed was, so lowest point is approx 5’ 10” and the ridge is well over 6 feet, I am 6’2” and it’s fine for me

When using a dual side by side set up as I do, then one of the scopes will always go down below the wall height before the other, so I do have to watch that, especially if is the guide scope as if I do not notice then causes issues as you would imagine….

[Swoop1]

Re the second pier height being insufficient, could you POUR a concrete base that is part above ground by the required height to raise it?

[scotty38]

1 hour ago, powerlord said:

Here's my scale model 'Wendy observatory'.  1:15.

Scope is my biggest 300pds.

Shed is a 6x9 metal on on ebay.. I think this will work, but will need limit control for low east or west.

Everything to scale. Basic eq mount made, so I can move it around and check.

There is no way that scope is balanced.... Amateur hour.... 🤣😂

[powerlord]

2 hours ago, adyj1 said:

Are you thinking of using the heavy-duty drawer runners, or v-groove wheels?

I'm more thinking a sort of captive wheel beyond either edge.

So as you (lets talk manual for now) push the roof off, it is free to tilt down as you push, till when it gets to the middle it is fully vertically lying next to outside of roof.

Need to find a good source of wheel/rack sort of solutions so I can see what is available. At present I'm thinking something similar to what one of my 3d printers uses. is that a v slot wheel ?

So they'd be some sort of guide/rack along the outside edges of the roof sections themselves, and on the shed, only 1 or maybe 2 v wheel sets. so as the middle clears the last one (which is maybe 1/4 way in, it is then free to 'fall' down the way. and with a bump stop at the end of the guide rack, that will rest on the final edge wheel, supporting the roof in it's dangling down mode ?

does that make sense ?

trying to learn about new stuff like this is interesting, but it is often a pain trying to find the right keywords to actually start finding the info you are looking for. I can see it all in my head clearly.. 😋

[adyj1]

You're right, I'm not sure I'm using the right terminology either, so I'll try harder 😉

I'll show you what I've done, but I'm certainly not suggesting it is the best way to do it. I just know it hasn't fallen off. Yet.  

I used Skelang U-groove gate wheels from Amazon in the end (rather than v-groove):

Probably engineering overkill (and I used 6 so that the roof doesn't 'flex') but I wanted a high level of confidence it would last longer than a summer ;-). (In hindsight, I've seen nylon grooved wheels that are a similar size but would probably have done as well).

Here is a picture of my roof mid-build. The dark wood is an extra run of old pergola struts which raise the sides of the roof and give me better clearance for my scope, which I decided to add during construction and now realise is a key contributor to the weight... (I extended the shed's back wall up to the lip of the roof, so that the dark wood roof base is actually only 3-sided):

 

I've seen proper gate v-channel used for the runners, but boy is that expensive 😮 - 12mm metal galvanised steel channel from Wickes at a pound a meter worked great for me (fitted the other way up to the pic). 

I have a 3d printer, and I would worry that it is asking a lot of the v-groove pulleys, they are quite small and I would worry about the weight of the roof.  

I'm not trying to deter you  - having seen your success so far I'm sure you'll figure a way to make it work. As I see it the challenge is to brace your roof sufficiently without adding too much weight.

Hope this helps

 

 

[powerlord]

Looking into it more, I'm thinking 2020 aluminium extrusion v slot.

This would be fitted to the edges of the roof, both strengthening it AND providing the rail, while adding not a lot of weight.

On the shed for each of the 4 sides of roof, there would be 2 opposing horizontal nylon v wheels just off centre.

at the end of the extrusion I have a hole through it and a pin that can go in, locking it.

This provide the final 'lock in' of the roof sections.

The extrusion on the edge outer corner will extend around 10 cm.

On the shed, a second set, this time of 4 wheels, will be mounted out the edge on a hinge so the set of wheel are free to be either horizontal or vertical.

You remove the pin, and as you push out each half of roof, it clears the centre wheels. It is now only supported by the hinged outer wheels. You now replace the pin.

So, as you push it further out, it will naturally get heavier at the outside and start to pivot down.

at the end of the extrusion there is the pin, to when fully hanging vertically the pin on top of the wheel hinge supports the light weight of the roof section.

I think I'll have to model this in solid works to see if it all actually works.

Stu

[adyj1]

Sounds like a lightweight way to do it, for sure. Looks like I might be wishing you did this before I did mine 😉 

Good luck! 

Ady

[ollypenrice]

I think condensation is a 100% non-issue. I have a number of metal-roofed roll offs and all I do is have them lined with sheets of rigid insulation material. These are corrugated roofs so the sheets only touch where they touch but, even so, there are no drips. If there were, I'd fix the flat sheets to the corrugated metal by using expanding foam. On two of the roll-offs I've built I used alternatives to corrugated steel but that is not a mistake I will make again. If you can make the whole thing in steel then I'd do so in a heartbeat.

Olly

[powerlord]

here's a dodgy animation of what I'm talking about.

 

 

[powerlord]

11 hours ago, ollypenrice said:

I think condensation is a 100% non-issue. I have a number of metal-roofed roll offs and all I do is have them lined with sheets of rigid insulation material. These are corrugated roofs so the sheets only touch where they touch but, even so, there are no drips. If there were, I'd fix the flat sheets to the corrugated metal by using expanding foam. On two of the roll-offs I've built I used alternatives to corrugated steel but that is not a mistake I will make again. If you can make the whole thing in steel then I'd do so in a heartbeat.

Olly

what insulating material did you use olly ?

stu

[adyj1]

10 hours ago, powerlord said:

here's a dodgy animation of what I'm talking about.

 

A rather whizzy animation, to be fair. The description comes to life!

[Stuart1971]

You do have to consider where you are in the country and what country for that matter, when it comes to material to build from, I personally would not use metal here in the UK, as condensation would be bad, it’s an issue with domes too, and the one thing you don’t want with Astro kit, is condensation.

I had  a metal shed in the garden a few years ago, and it was well vented, but for a few months of the year the inside walls were soaked constantly..it really put me off using one for an obsy, the wooden one I have now, is perfect, and the only time I use the dehumidifier, is after a session for a couple of hours, as there is usually some frost on the inside of the roof, where is been folded open, and it gets rid of that very well.

Just my twopeneth…👍🏻

[powerlord]

2 hours ago, Stuart1971 said:

You do have to consider where you are in the country and what country for that matter, when it comes to material to build from, I personally would not use metal here in the UK, as condensation would be bad, it’s an issue with domes too, and the one thing you don’t want with Astro kit, is condensation.

I had  a metal shed in the garden a few years ago, and it was well vented, but for a few months of the year the inside walls were soaked constantly..it really put me off using one for an obsy, the wooden one I have now, is perfect, and the only time I use the dehumidifier, is after a session for a couple of hours, as there is usually some frost on the inside of the roof, where is been folded open, and it gets rid of that very well.

Just my twopeneth…👍🏻

I think you are right that it is an issue that needs addressing. If you do nothing, there will be lots. But unlike a shed, where you don't mind it and just leave it, I think it can be tackled pretty easily with  a simple thin barrier of some sort of insulation - that stops humidity getting to the metal, and the insulation stops its surface getting cold enough to form on top.

I think for me, I'm pretty much convinced metal shed is best. And I'm probably going for a 9x6 - it's not quite big enough to not have to worry about where the 300pds is pointing if it's on - but I don't want to have a massive shed just for the month or so a year I have the 300pds setup - I can put up with just having to be more wary of where my gotos and tracking goes when I'm using it. And that give a 4.5x6 roof section, which feels managable for a manual slide, though tbh I think the design will be more optimised if it's built motorised from day 1. I'm still trying to work out in my head what that will look like, but at present I'm thinking 4 steppers - one each corner, driving fixed toothed belts. In the new year I can get a bit of 2020 extrusion and some v wheels, and put a POC together with a stepper motor and see if it all works in principle. I'd like the whole roof to retract or go back in under 5 seconds.

out the box, metal shed is gonna be flimsy, etc and need work. But so would an off the shelf wood one. And wood has doubled in price - you'd not make that nice tongue and groove shed of yours for that money now.

stu

p.s. joking about 5 seconds. though that would be cool.

[EarthLife]

Also, metal sheds make for very nice faraday cages  .. could be good, could be not so good.

If you have any wireless comms between shed/house etc using antennas inside the shed then communication could be severely restricted. if it becomes a problem then just mount say any wifi antennas on the outside of the shed.