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Small Dome Observatory Plans Cheshire


Astropedro
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I've been in and out of both visual and imaging for the last 12 years.  Put simply, I'm well aware that if i had an observatory, i wouldnt be able to leave this hobby for any great length of time regardless of family life, golf commitments(sorry😄), work constraints or anything else that consumes time for that matter. I love astronomy........but........... the setting up of my gear in the dark, with not so good eyesight anymore, has put me off slightly.

So..........I recently built a large 18' x 6' tongue and groove shed to house my tools and for some home business storage.  This has freed up an 8' x 6' area (threabouts) where my old metal shed stood.  I still need to completely empty it and dispose of it.  My partner has no problems with me building an observatory in this space as she too shares an interest in astronomy. Lucky me!! She did say, however, so long as it is aesthetically pleasing.

With this in mind, I would very much like to build a 7' or less diameter dome observatory from leftover timber I have from building my shed and decking.  I will have to get some ply sheets for the dome frame and skin but I'm confident I have enough timber for the bottom half of the obsy whether that ends up being square, round or hexagonal etc.  I was thinking of following "How to build a home observatory" guide on the BBC Sky at Night as it seems to tick a lot of boxes.  I would like to automate it as much as possible too.

My house faces east and I have uninterrupted views to the north, east and south.  At present, I have no pier but dont mind making one from concrete or getting one made from steel. My current mount is an exos-2 pcm8 and I have an unused Altair Starwave 70ED Triplet APO.  I also have a Canon 1100d and a  QHY5ii426C for imaging.  I dont mind getting more gear as needed especially if what I already have is unsuitable.  My primary interest is deep sky imaging but I'm toying with buying something portable to go to a nearby dark site to observe and maybe some planetary imaging.  Was thinking maybe a Nexstar 5 or 6.

 

Anyway.........I've read a fair few threads of SGL members building their own observatories ( WOW!!!) and I would love to hear from you regarding your thoughts on my plans for the obsy and my current gear etc.  I would like to start prepping the ground this weekend if it isnt too cold or wet so any advice would be gratefully recieved.  I have an electric mixer and no shortage of power/cordless tools and diy knowledge and confidence, however, the dome aspect of the build has to be a challenge!!

 

I'll post some photos of the area to be used once its cleared.  The base will be concrete with an isolated concrete cube for the pier.  So long as I have a good idea of the design over the next couple of days, I'll get the concrete base and pier base in over the weekend.

 

look forward to hearing your thoughts.

 

Pete 

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To be honest, if you look through the DIY observatory section you will find very few DIY Domed observatories.  There are several reasons, which is why most of us turned to traditional roll of roof designs.  

Domes are complicated to construct, especially in wood.  It can be done, but the results tend to be extremely heavy and doesn't lend itself to be automated as a result.  Also, every joint is a potential weak point where water can ingress, and to get a decent dome you would need quite a few segments which means lots of potential leak points.  If you MUST have a dome then look at picking up a second-hand commercial fibreglass one and either a matching base, or construct the base from brick or timber depending on your skill set (or budget if you are using a builder).  As a guide the RRP for a new Pulsar 2.2m domed observatory with base is around £3795

There are advantages and disadvantages using domes over traditional ROR construction.  Having the dome driven is IMO a must as the slot the scope observes the night sky with is narrow and the dome will need rotating regularly.   Having a light (compared to a wooden)  GRP dome makes motorising that fairly easy (Pulsar make kits of parts to do so).  If the dome is heavy it will take big motors and draw a lot of power to achieve that.  It's doable, and some members have an almost fully automated domed observatory, but what pitfalls they had to overcome in developing those systems, how easy it was, and whether in hindsight they would do that again is another thing.

You might also want to research any planning regulations your local authority have.  There are height restrictions within certain distances from any boundary fences / hedges and planning application may be needed.  Also check with your household insurance company to see if an observatory is covered under your existing policy.  Some only cover sheds as outbuildings and workshops or observatories are classed as additional cover.  Some insurance companies may decline cover for a dome observatory as it's more of a target and "advertises" the fact that expensive equipment is contained within.  To anyone passing our house, my observatory looks like a large shed, in keeping with the other sheds in the garden, so for us cover was provided.

Other than that, I would advise anyone who has the funds, space and ability to build an observatory to do so.  It takes observing / imaging to a new level of convenience.  

  

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Thanks for the responses guys.  

 

I take your point regarding weight Malcom but unfortunately my budget just wont stretch to a new dome at present.  I have tried the second hand market and cant see much especially in my area(northwest).  With this in mind, I'm still leaning towards a homemade plywood and possibly fibreglass covered dome on a timber clad base.

  I build campervans for a living and I've noticed that 3.6mm ply is fairly strong and very light.  Cant say the same for 25mm ply that I would have to use for the dome frame but I'm curious to work out what the timber weight alone would be.  Then if it's already a hefty thing, maybe just fibreglass tape all the joints, sand down any rough edges and give it a few coats of what I can only imagine to be very expensive waterproof exterior paint of some sort.  Fibreglass on the exterior sheets might be an option too.

I'm ok with planning so long as I dont go over 2.5 metres high which I have no intentions of doing.  Was thinking of 4 or 5 foot sides and a 3.5 foot high dome.  

Automation...........Again point taken Malcom.  I have no doubt I will end up having to cobble together some sort of drive system rather than something off the shelf if i go down this route.  I can see windscreen wiper motors or something similar...............Hopefully I can keep the weight low enough for this not to be too much of a headache.

Never even thought of insurance............I'll get on it as wont be long before this gets mentioned by my partner!!

Swop........good point.....I will run a length of plastic pipe through the concrete base for cables galore.  

Although I'm fairly confident in my skillset to build this, I do see complications. The door, making it weatherproof and secure, and automation.  Hopefully you wonderful ladies and gentleman can assist me when I stall or stumble.

 

Why do I get the feeling this is going to take longer than I thought...........

Completion before xmas perhaps?...............pleeeeeaaase.......😊😊

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Pete,

A pent roof shed with roll off/ on capability will still look pleasing- no less so than the current metal shed. This will have the advantage of avoiding the complexity of building a dome and might also include a bonus pergola to support the roof?

If the pergola idea doesn't cut it, fold away supports can be added like in the build project in this months Sky at Night mag.

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I built a 3m/10' Baltic Birch, plywood dome three years ago.
Despite using the "finest" marine sealer, at £40 per tube on the joints, my dome now leaks like an inverted sieve.

Successful plywood domes usually lead to fiberglass overcoats.
The cost is horrendous, time consuming and smelly. The result is an uneven, matt, chopped strand appearance.
Not the high gloss you had hoped for. Not unless you make a mold and lay up your own gores or larger segments.

Domes limit your useful space if you go for a round building. Or an octagon as I did first time around.
A rectangular building provides far more useful room.
Unless you have unbroken views to the east, south and west then observatories are only useful for refractors.

I like domes and I am presently converting an agricultural dome into a 14' Ø observatory.
Six months in and I am still struggling [daily] with the 3D shutters. 
I am retired and can throw countless hours at the project in the privacy of a detached, rural, back garden.

Peter Drew's barrel domes, at The Astronomy Center, are a far better alternative to a hemisphere.
Flat sheets of aluminium, with a nice gentle curve and lots of room from the square footprint.
They need rolled hoops for the edges.  I couldn't get a local engineering company with a machine bender to make the hoops.
Woodworkers could make a Baltic Birch ply copy of these all metal, arched domes.
The appearance is entirely a matter of taste. My wife didn't want a huge one dominating the back garden.

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Pete,

I know you have your heart set on a dome, but for the reasons mentioned above, and covered in my previous post I would seriously urge you to reconsider your plans.  You want something that is going to be secure, dry and doesn't require a lot of maintenance.  Granted it's now a decade ago since I built my 2.2m x 4.8m observatory, and with current shortages building materials have shot up in price, but I still managed to come in at under £2K for the building materials, £500 of that was on quality shiplap.

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This gives me a 2.2m x 2.8m scope room, and a 2.2m x 2m warm room (now workshop).  In that 10 years the only issue I have had has been a small leak that developed 18months ago but a felt patch fixed that.  Other than that  I replaced the door to put a window in it and it's now treated to an annual coat of dark oak preserve

obsy2016.png.30d6671353435bcdf5b204a5c894c400.png

 

Electrics:

Seek the advice of an qualified sparky.  It will need armoured cable, and that typically has to be on its one circuit from the consumer unit.  I was lucky, we have a feed to a consumer unit in a brick built shed, which already had 2.5m  twin and earth armoured to a light on the patio which could be reutilised.   You can't simply lay some armoured cable on the ground, it has to be surfaced mounted or buried in accordance with  part 19 rules.

Data:

Lay in external CAT 5 (or 6) between the observatory and the house.  Also use ducting with curved pipes rather than sharp bends, and feed in a couple of draw cables whilst assembling the ducting.  When pulling through low voltage power or USB cables between the observatory and mount tape another draw cable to the front of the cable so you draw through a replacement at the same time as the USB cable.

Alarm:

Fit some form of alarm system.  Having 120bd sounder going off 1m away is a big discouragement to anyone who ventures in there when not wanted !

 

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May have spotted a used fibreglass dome.  Trying to negotiate for it as it's a bit over budget and a 4.5 hour drive away in what would have to be a rented flatbed truck or Luton van.  It's a tiny bit taller than I would have liked too but I can always sink the base a few inches so long as I sort out good drainage.  It looks like its functional and just needs a clean up and maybe a good coat of paint.

 

Will let you know how I go on.

 

Still undecided if i dont secure it.  I did originally plan on a ror but talked myself in to a dome.  Now, after speaking to you guys, I find myself torn.  I read somewhere on here that you can still image in high winds with a dome.  Is this true or are you still at the mercy of the elements somewhat?

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7 hours ago, Astropedro said:

May have spotted a used fibreglass dome.  Trying to negotiate for it as it's a bit over budget and a 4.5 hour drive away in what would have to be a rented flatbed truck or Luton van.  It's a tiny bit taller than I would have liked too but I can always sink the base a few inches so long as I sort out good drainage.  It looks like its functional and just needs a clean up and maybe a good coat of paint.

 

Will let you know how I go on.

 

Still undecided if i dont secure it.  I did originally plan on a ror but talked myself in to a dome.  Now, after speaking to you guys, I find myself torn.  I read somewhere on here that you can still image in high winds with a dome.  Is this true or are you still at the mercy of the elements somewhat?

Good luck with getting the dome. :thumbsup:
Don't bury it! Height is everything when the planets are low.

You can image provided the wind is not blowing directly into the dome.
I peg a doubled wind break net across the lower half of the observation slit if the wind is a problem.
Morning solar imaging is certainly possible with a Sou-westerly. I do  it all the time.

You get a nice sense of shelter in a dome.
Allowing you to observe and image in mere moments from making the decision to go out.
Close up in seconds when you feel the rain in changeable conditions.
I would no longer be an amateur astronomer without my [raised] dome.
It completely transformed my retirement.
 

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I have both a RoR and a dome. I managed to get a pulsar dome second hand and last year refurbished it. It's not automated, did think about it but eventually didn't bother. 

I personally don't prefer one over the other although on cold days in winter I like sitting in the warm room in the RoR and the scopes out in the cold, lol. 

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Well.........he won't budge on price and its going to cost me at least £250 to collect it by the time I've hired a van bug enough and factor in fuel for 9 hours driving.  It looks like a pulsar.  9 foot high by maybe 7 foot wide.  Needs a good clean and a coat of paint.  Other than that it looks fine.  Asking price is £1500.  If I could get the price down 2 or 3 hundred I would probably buy it.

Anyway.......loving your obsys guys n gals.  All good advice and I thankyou for your sound reasoning and arguments for both domes and roll offs.

Stuart.....love the simplicity of that!  Looks a nice shed too.  I don't need a warm room as my living room/dining room is only a few feet away from where it will be sited.  I already have an outdoor socket I can tap into for power too.  I also have a self build large shed and workshop right next to where the obsy will go too.  Could always make room in there for somewhere to sit with a laptop etc.

That's a nice setup malcom.  I remember reading some of your posts when I was living in Spain a few years ago.  I may still go down the ror route yet.  I have a bbq and decking area next to the site though so i would have to negotiate with my partner as it will alter the plans somewhat.

Just thinking.....is a used pulsar worth £1800?  If it even is a pulsar I wonder.....

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33 minutes ago, Astropedro said:

 

Just thinking.....is a used pulsar worth £1800?  If it even is a pulsar I wonder.....

I'm guessing that its the one in Kent

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I'm not sure if its a Pulsar, if it is then it's possibly an early version.  But at £1500 plus the delivery that's still half that of a new one.

The advantage of new is that that it will have 12 months warranty, and if you want to spread the cost, choose the three instalment plan via paypal. If you later want to motorise the dome you know the drive will fit and will work.

Bottom line is that its your cash, and ultimately your observatory.  This DIY section is filled with examples of home build observatories from £300 sheds from Argos through to £10,000 fully automated domes.  We all built them the way we did for various reasons and had different budgets.  Do you pay £2K for a second hand dome, petrol, hire charges, and any other expenses associated with renovation (the rollers look as if they need replacing - something a friend had to do when he got a second hand dome), or pay £3K for a new one that won't need anything else and should work out of the box.  - Only you can make that choice

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Be aware that if it is a mk1 Pulsar (Possibly 2.1 metre rather than the current 2.2 metre) that you will have problems with the Pulsar automation. From what I've read on other threads people have had no end of trouble.

I did look into a dome using a Pulsar short-wall dome on a fabricated base, but in the end decided that the costs were multiplying out of control. Went for a RoR in the end despite the shelter from the wind that a dome provides.

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25 minutes ago, DaveS said:

Be aware that if it is a mk1 Pulsar (Possibly 2.1 metre rather than the current 2.2 metre) that you will have problems with the Pulsar automation. From what I've read on other threads people have had no end of trouble.

And this throws another variable into the works.....

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Yes spot on......that's the one Malcom.  Its the only one I can see anywhere on the Web second hand.

So I'm guessing I won't be able to use an off the shelf automation kit if I went down that route.  Nothing is easy is it......🤣🤣.

My head hurts.......🤣🤣🤣

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Life is never easy :)

I think you need to find out from the seller exactly what make and model the observatory is, and if they are vague, find out its history and how they came to have it.  If it is their own observatory then they should know its age, make and model.  If it does turn out to be a MK1 pulsar then yes, based on the above information an off the shelf ready to run drive system would require a lot of fettling to get it to work.

EDIT:

A quick google and came up with this 

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Which confirms its a pulsar.  But as their new domes are totally smooth and unsegmented then this suggest it is an early version

In fact further research and its an original - have a read of this document and you can see one of the originals form 2000 which is the same as the one in the listing

Edited by malc-c
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Thanks for the detective work malcom.  Made my mind up....its not worth that much.

I've just enquired on astroshop.eu regarding a nexdome.  Seen mixed reviews but mostly positive.

Where have you seen a pulsar for £3,000.  On their site they're closer to 4k.

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I really would not go down the dome route unless you plan to motorise too, as you will soon get fed up with going outside to move it round…also they are prone to condensation, so you will need to cost one of those into the price, and best to get a desiccant version, more expensive to buy and to run, but will work very well down to 1 degree. I went through all the thought process you are going through two years ago, and am glad I went the way I did…
Just my twopeneth.. 👍🏼

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No that dome isn't worth it. I bought a 2.7m full height pulsar dome for £1,500 a few years ago. It's not automated and I personally don't mind. I do however sit in there under the stars listening to the owl's and foxes. Attached is my refurbishment. Long story but I had moved house and left the dome till I could pick it up during the first lockdown and thieves thought it contained something nice and tried to break into the empty dome, lol. It was a nice project though. 

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My apologies, the price was for the short height dome - the 2.1m standard is indeed £3795

The nexdome is listed as being under £3K at £2960 (inc VAT - which presumably is at UK rates?).  But being outside the EU you may have to pay duty to import it into the UK following Brexit.  

I'm hoping its just their website that is at fault as I wanted to find out how much the shipping cost would be given the size, and this was the result when I placed the product code into their website on the shipping page, yet the table below shows the standard UPS for <44kg being £78.51, up to £194 for UPS Express

 

shipping.png.702402be3dce904f73bf53682b7d1873.png

Hopefully they will get back to you to confirm the price, shipping and if any additional taxes or duty would be payable

I know I've said it's your money etc, but you could get a far better alternatives for the £3k  -  If you do reconsider and look at traditional wooden ROR observatories, DONT place an order with Home Observatories UK - other forum members have been waiting more than 12 months for their observatories and two have resorted to recovering their deposits via the small claims courts.

Even though my observatory is 10 years old, the equipment is always dry, and I can be up and taking that first image in less than 15 minutes on a good night.  I don't have to worry about any issues with the dome matching the Earths rotation, and thus can run sessions all night from the warmth of my living room via RDC to the observatory PC.

That observatory that Stuart built from a small summer house looks very sturdy and practical.  Such a building would make an excellent replacement for the metal shed you currently have.  I'm sure they can offer larger if you wanted more space.  My scope room is approx.  6.5' x 8'  and I can easily walk around the 200P without having to limbo around it !  I would even wager a pack of donuts that if your went down the same route as Stuart you could build the base, purchase the building and materials to modify it, and lay in all the power and data for the same amount you would spend on just purchasing a commercial  dome.

But as I said, its your money, your choice and your project... 

 

 

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Nigella raises another point.  Security.  The majority of low life are still able to recognise what a dome observatory is.  Even if they don't, the fact that it doesn't look like any other domestic outbuilding draws them to it.  If you live in the sticks then things may be different.

Her video also highlights that you still have to factor in the construction of the floor and base.  Personally give UK weather I would have used exterior grade ply rather than a particle board for the floor, which at todays prices can add a further £200 to the budget.

 

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