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Shelster1973

Contemplating Obsy.....

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Have just moved house and am contemplating building myself an obsy.

The developers have kindly left me with not the best garden in the world (unless I was a mountain goat) as you can see in teh pic below

08B69DC6-4D4F-4743-ABC5-930893D198F4.jpeg.8665b27577d45953f87fca7a6192bfc0.jpeg

The garden points north west and I can just about see Polaris to get things aligned.

What I was thinking is to do a roro towards the left of teh garden as seen above with the roof rolling over the bank.

Was just wondering if people have any good suggestions?  Am also trying to work out a budget for it, so any ideas on coatings?

My thoughts for the rolling gear would be to use the captive ball rollers that you see inside plane cargo areas.  That way I do not have to worry too much about perfectly parallel rails.  Am also probably not going to have a warm room as house is very close and can link with Cat 6 cable, so can remotely control everything from my spare room.

Base wise will probably keep it very simple and just have the obsy sat on blocks, with a large concrete block for the pier, so all is isloated

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Use what you have you have to your own advantage: :thumbsup:

I'd grab as much height on that bank as you can. To avoid later blocking of your view of the sky.

You don't need a big flat slab of concrete. Use buried, pre-cast concrete, carport 'anchors' and timber posts.

Then build a level plywood floor on joist hangers hung off the posts. Or even use long coach bolts and notches.

You can use the space underneath the floor for garden toy or lawnmower storage if there's room.

Be careful you don't put anything too tight to the boundary fence in case 'Planning' is required.

Local conditions vary.

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Aye, have thought of going up the bank a bit, but worried about encroaching on sight lines for neighbours.  If you stand on teh top of the bank then you easily see into peoples bedrooms.  Yep, it is that high

Like the idea of sunken posts though.  Will give it some proper thought when I get back home from festive visitings

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Hi, as you are not having a warm room due to close proximity to the house have you considered a dome ? This could be installed high enough up the bank so that when your scope is at it's lowest usable altitude it can't see anyones bedroom window just to appease the local complainers 😋 like others on here including myself once you start on a self build the costs slowly mount up which makes a dome price very appealing and super easy to install. Just a though mate 👍

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Depending on budget, and all things considered, I think a commercially built dome option would probably work out more expensive than a ROR. A sliding roof can be relatively inexpensive, depending on what covering you choose to use.

It is also surprising how the total costs can escalate, so would suggest careful planning of your budget. My build costs follow the pareto rule perfectly, with exactly 80% of the costs being accounted for by 20% of the materials.

Looks an interesting site there but as Rusted said, use the landscape to your advantage in your design. If planning consent is a consideration, I wonder where they would take the average surrounding ground level from?!

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Thanks for all the advice so far, greatly appreciated. 

Did think of a dome, but have ruled it out as am not too keen on the aesthetics of them.  Know they are the best for functionality and space, but......

Also for the groping as high as I can, am not wanting to build above bottom level because as well as the over looking peoples houses issue, behind the back fence is a public footpath that it on open ground/parking area, so do not want to advertise the fact that there is something interesting in there by it being visible.

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I wondered what was behind the fence.  Yes, a dome would no doubt attract attention.  A relatively unassuming garden shed is what I went for as an observatory - nothing posh looking.

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Posted (edited)
On 09/01/2019 at 22:48, Astrokev said:

Depending on budget, and all things considered, I think a commercially built dome option would probably work out more expensive than a ROR.

.

Edited by Guest

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By having the roof rolling off over the bank you mean to the right in the photo?  Or rolling away from us?

I can appreciate not wanting to stick it on top of the bank, advertising your telescopes to all and sundry, but I might be tempted to set it into the bank a bit, even if only a couple of feet as a way of utilising space that might otherwise not be much use.  You could use railway sleepers or something like that to make a retaining wall.

I might still be tempted to put it on the right hand side, but that's hard to judge without a better feel for location.

In fact, a few more sleepers on the other side and you could backfill behind them with the spoil to make a little raised seating area that would be in the sun most of the day.

I'm getting carried away now, aren't I? :D

James

Edited by JamesF
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33 minutes ago, LeeRich said:

Obviously !! But with a considerable amount of less effort and hidden costs as  you are realising Kev! As for an unassuming shed if I were a thief i would look for tools rather then what a dome may house ? but each to thier own. It was merely a suggestion 😋 I will be most interested with your choice and progress. One to follow for sure.

Sorry maybe I misunderstood. I thought you said a dome price was appealing. I didn't really have any hidden costs and certainly nothing specifically linked to the roof. I don't have my cost list to hand (typing this on my phone) but from memory my roof cost around 400 in total. EPDM was the most expensive element, but that was my choice. I could've used felt for a fraction of its cost. The rail and wheels were just over 100 as I recall. Other than that it was just timber and a few sheets of OSB.

@Shelster1973 you say a dome is best for functionality and space. Not necessarily. It's obviously down to personal choice and domes certainly look the part, but the slit can funnel air currents in front of the scope as compared to a more open design, and the dome needs to be moved whenever you change target or during long imaging runs (automation is possible of course, but with that comes extra effort and cost). 

I personally favour open designs so I can see more of the sky, but that's just personal preference. 

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On 26/12/2018 at 13:02, Shelster1973 said:

 

My thoughts for the rolling gear would be to use the captive ball rollers that you see inside plane cargo areas.  That way I do not have to worry too much about perfectly parallel rails

That sounds a really interesting approach! I've never seen those used before. Look forward to seeing that come to fruition if you decide to go down that route. 

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1 hour ago, Astrokev said:

I personally favour open designs so I can see more of the sky, but that's just personal preference. 

Good for you Kev but that's exactly your point.....personal peference.

There is no hard ship in moving a dome between objects, ridiculous statement. Also why are all professional observatories domes and not ROR ?? Surely that is testament to it's design is it not ? Hense cascading down to the amateur  🤣

I love my dome even more so then my previous ROR but like you say it's personal peference and I would never go back to a ROR now i have the luxury of a dome. 

Edited by Guest

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If you look at my thread you'd see I used large industrial drawer slides for my roof. While I tried my best to build everything plum and straight, carpentry is not my day job, so the building is ever so slightly out of true here and there. The slides gives a little so while generally they are parallel it's not perfect. They are perfectly parallel to the ground though, achieved via self leveling laser level.

One of the reasons I use the slides is that you don't have to worry about a lot of things like how to keep the roof from lifting in gusts or support beams for the roof to roll onto. It also means (other than my lack of workmanship) that it looks like a regular garden shed when closed.

Edited by cotak

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Back in the 80's I built an Octodome on a 3 x 3 mtr , 1.5mtr high wall base. Plenty of roof height (2.7mtr) and space to move....

The sliding top also used those industrial sliding door rails (excellent!) and it has a couple of doors on one face to view low objects without sliding the roof back. I also "acquired" a couple of reject double gazed windows from the high speed train and added them. 

This housed my 12" f5 used for visual SN search.

Worked 110%.

 

Observatory 1984.jpg

canopus320_1984.jpg

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As a recent builder of a plywood dome I would warn of the huge hidden costs.
The power tools alone added to the bottom line. I needed them for vital accuracy.
It would have been far, far cheaper to have bought one of the popular GRP models.
They just didn't do one large enough which would take my big refractors.

The presence of No Man's Land beyond your fence is a very serious matter.
Not only is it wide open to security issues but the dangers of any "amateur" excavation placing the public at risk.
You don't want any inviting, flat roofs which short circuit the added security of that valuable drop.
So stay away from that fence!
Plant an extremely prickly hedge below the fence now so it has a chance to grow. Firethorn? Berberis?

This is a very difficult site by any standards. So a dome is completely out of the question.
A dome shouts that there is somebody in there peeping out from the darkness.

A roll off roof with walls just above head height makes you invisible.
You can't see them below the wall height because your view is blocked.
There are no heads moving about in full view.
You may lose a bit of sky but it is well worth it.
What the eye can't see the heart won't worry about.

No widows on the side facing any other buildings than your own.
No windows on the side facing the fence for security reasons.

My earlier suggestion of buried concrete carport anchor blocks would protect the bank from major excavation.
I'd probably split the roof into two halves moving parallel to the fence.

Use free image handling and drawing software on your photos to see what works best for you.
You can clone various materials onto the picture to see whether planks, vertically grooved ply or blocks make most sense.
A green surface might disappear into the lawn. A row of potted conifers or tall shrubs so soften the appearance?
A trellis is traditional and can be freestanding on a rolling roof support structure to disguise the building's presence.

 

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7 hours ago, LeeRich said:

Good for you Kev but that's exactly your point.....personal peference.

There is no hard ship in moving a dome between objects, ridiculous statement. Also why are all professional observatories domes and not ROR ?? Surely that is testament to it's design is it not ? Hense cascading down to the amateur  🤣

I love my dome even more so then my previous ROR but like you say it's personal peference and I would never go back to a ROR now i have the luxury of a dome. 

Hi Lee. 

All I was trying to do was respond to the comment that domes are best for functionality. I'm sure moving the dome between targets is indeed no great hardship. That wasn't my point. My point was that, based on my own experience, it is one more thing to consider when doing a functional comparison of designs. Shelster was asking for suggestions and views and I was simply offering thoughts to consider. 

Read any textbook about obsy design and  the comments I made are generally mentioned. Again just something to bear in mind. There are of course advantages of a dome - they block outside light getting in, and offer more protection against wind, which can be downsides of RORs. At the end of the day the builder should do their own comparison of pros and cons and decide what is best for their situation 🙂.

As for professional obsys using RORs, the size of the roof needed would create a massive obstruction when rolled off which is probably a major reason they're not used. 

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5 hours ago, Merlin66 said:

Back in the 80's I built an Octodome on a 3 x 3 mtr , 1.5mtr high wall base. Plenty of roof height (2.7mtr) and space to move....

The sliding top also used those industrial sliding door rails (excellent!) and it has a couple of doors on one face to view low objects without sliding the roof back. I also "acquired" a couple of reject double gazed windows from the high speed train and added them. 

This housed my 12" f5 used for visual SN search.

Worked 110%.

 

Observatory 1984.jpg

canopus320_1984.jpg

Back in the 80s I was  trying to figure out which nappies were more gentle on my bum :D :D 

But honestly, this is an awesome scope. 

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Thanks!

Yes, it was one I designed and built....worked very well......

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It made the front cover of the popular Japanese astronomy magazine....

canopus320_1small.jpg

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Wot Kev said.

A dome does provides more shelter until you have to point it straight into the wind.  ⛄
A dome largely blinds you to the night sky except in clamshell form.
A dome can have thermal issues. So called: "Dome seeing" as built up warmth flows out of the slit.
A dome can provide deep and comfortable shadow for the observer during solar imaging.

There really is no best observatory for everybody.
Start with an open mind and write down ALL the pros and cons and be brutally honest.
Ask yourself whether you have all the skills to put something together yourself.
There is no loss of face paying for professional help. Nor buying something off the peg.

You must have enough funds AND FREE TIME to complete the project.
Double or triple both if you follow the usual amateur build.
An observatory without a weatherproof roof, or dome, is no observatory at all.

You do not need an observatory to be a serious amateur astronomer.
Some of the best imagers in the world do not own an observatory.

Old age can provide an incentive for more shelter.
No more carrying heavy, wet or icy stuff in and out and you enjoy almost instant gratification.
An observatory can rekindle lost interest from cold nights wasted on a lawn watching the clouds roll in.
With any proper shelter you can be quickly taking advantage of short clearances because you are always set up.
It provides somewhere to sit quietly instead of watching Netflix.
It should provide serious security for expensive equipment.
If the observatory does not provide all these advantages then why bother?

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Old age can provide an incentive for more shelter.
No more carrying heavy, wet or icy stuff in and out and you enjoy almost instant gratification.
An observatory can rekindle lost interest from cold nights wasted on a lawn watching the clouds roll in.
With any proper shelter you can be quickly taking advantage of short clearances because you are always set up.
It provides somewhere to sit quietly instead of watching Netflix.
It should provide serious security for expensive equipment.
If the observatory does not provide all these advantages then why bother?

Totally agree.  I go to astro camps and set up monthly throughout the year.  But in the winter months I am restricted to staying at home in Bortle 8.  I would not bother imaging from my LP location if I didn't have an obsy but having one with the kit already set up I can get up and running within a very short time.

Obsy's also provide a good wind break.

Carole 

 

 

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2 hours ago, Rusted said:

It provides somewhere to sit quietly instead of watching Netflix.

Now that one point is enough of a reason in my book to make an Observatory a worthy thing.

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Again, that is all for the input. Am just looking for ideas and thoughts at present, so please don’t go falling out with each other over this. Everyone’s input is valuable. As they say, apionions are like a***s, everyone has one and they mostly stink 🤣

anyway, here are two more pics of the proposed space but taken from my bedroom window so you can get a better perspective of things. Plan now is to manipulate one of these on my iPad and sketch a rough idea of where I want it730FD093-62A8-42F9-BA32-04896EA630F7.thumb.jpeg.cdfe10b7e9fad232867f41e8a514929a.jpeg4C567FFB-45C5-48D1-88E7-CEA7F13F5402.thumb.jpeg.a816f5d1f0653a5b7d1444b12f90bff1.jpeg

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3 hours ago, Rusted said:

There really is no best observatory for everybody. 

You must have enough funds AND FREE TIME to complete the project.
Double or triple both if you follow the usual amateur build.

Old age can provide an incentive for more shelter

An observatory can rekindle lost interest from cold nights wasted on a lawn.

Agree on all points, especially those above!

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Good for you and, like many, I'm one of those that has never looked back having built mine.

You will not find a definitive answer here as to what type to build.  Mostly because there isn't one, but also anyone with one will probably propose and support the type they have, be it ROR or dome (or some other very clever designs that have been presented in other builds).

You need to decide how much room you are willing to, and can, dedicate to the observatory and see what best fits this footprint whilst providing all the points you need it to.  Domes generally, in their standard form, take up less room by way of overall footprint.  However, ROR's are generally easier to control if you intend to automate or motorise at a later stage as you have no mount/dome synchronisation to consider.

I don't favour either, I think they both have merits, but it must suit what you want or need, not what has suited other's needs.

Good luck with the build whichever route you end up going, I'll keep a keen eye.

Edited by RayD
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