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JamesF's observatory build


JamesF

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I've been promising myself that I'd build an observatory for years, but life has just got in the way a bit and I never managed to get started.  Given recent events with my brother however (see posts elsewhere) I decided that I should really get on with it, so ordered some of the materials with the view that if I had the stuff here then I could work on it as time was available.

My plan was always to build in the "upstairs field" (a name given unintentionally by my son to the field at the top of the slope in front of the house) but at the moment there's no easy way to get power there.  That may still happen in the future, but for the time being I had to look elsewhere, which has not actually been too easy as very little (almost none) of the ground around our house is level and some of what is level merely acts as a collecting point for run-off water when it rains heavily.

My chosen site is this, which is next to "The Beer Shack" (which already has a power supply that can be used for the obsy).  The closest four stakes represent the corners of the actual building with the last one where the roof will roll off to.  It's flatter where the cement mixer is, but there was about 100mm of standing water there for much of last winter ?

obsy-build-1.jpg

The size of the obsy will be 4.8m x 2.4m including a 2.4m x 1.2m warm room at the far (north east) end.  I intend to have multiple piers to allow a permanent white light/Ha solar rig to be set up on one with night-time kit on another.  My design isn't too different from Astrokev's current build, but I don't yet know how tall my piers are going to be so I don't know how high the walls will be which in turn means I'm not sure where the door is going to end up.  Once I have the floor deck built and can check sight lines I'll make those decisions.

This gives a better idea of the slope.  I'm not entirely sure how the corner of the stone wall appears to be vertical, but the shed on the top right looks to be leaning quite significantly (which it doesn't).  Local gravitational anomaly, perhaps.

obsy-build-2.jpg

And from the warm room (north easterly) end:

obsy-build-3.jpg

The other major compromise with building here is the view to the south west.  Or more specifically, how some damn fool built my house in the way without considering that several hundred years later I might want a better view.

obsy-build-4.jpg

The view to the south east is similarly obstructed, but by a mature ash tree.  However, I went out the other night and could clearly see Jupiter over the roof of the house so I don't think it will be too bad.  The ash tree is probably on borrowed time too, though I'd not remove it just because it was an obstacle to astronomy.

Once I'd mowed the grass I wasn't entirely happy about the steepness of the slope.  The floor deck will be built off six concrete pads and the pad at the bottom of the slope would have been over 600mm high.  To reduce the height a little I decided to move everything about another metre away from the house.

That done, this afternoon I started digging out the space for the first two pads. Having the right tool for the job should save a lot of time ?

obsy-build-5.jpg

Sadly I was a little slowed down because I managed to jump one of the tracks off the digger.  I knew I needed to check it but I forgot and paid the price.  Fortunately it wasn't too hard to lever back on with a long steel bar whilst holding that side of the digger in the air with the bucket and running the track forward (not recommended practice, I imagine, but probably happens far more often than anyone will admit to ?

I got the shuttering in for the first pad late this afternoon, recycling the base of a trailer in the process, though I have to admit I'm not entirely sure how reliable the ply is any more.  It may not look it, but the spirit level does actually say it's level in both directions.

obsy-build-6.jpg

I managed to get the shuttering in for the pad on the left (also recycled, this time from a shelving unit that has seen better days) as it was getting dark.  Need to check the levels again in proper daylight.

I'd really like these two pads to be a bit lower, but the top of the one in the photo above is only 150mm above ground level and I'm not sure I want to go closer to the ground than that with the timber.  Perhaps 100mm clearance would be sufficient.  I shall ponder on it before I start the next one.

James

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There is actually an ancient (Neolithic?) hill fort less than a mile and a half away, where a pot containing a large number of Roman coins was found in the 1940s.  I've not had any such luck here though.  I did find a very badly corroded French coin from the reign of Napoleon III in the veggie plot a few years back, but other than that my interesting archaeological finds have been limited to dozens and dozens of old-style (thick glass with a tapering neck -- people older than 45-ish who grew up in the UK will probably remember them) milk bottles and a quern stone from a domestic-size grain mill.  The Napoleonic coin is interesting though.  This area has a long, long history of agriculture and is really quite poor overall, so probably not a lot of population movement has occurred outside the locality historically (I'm told the farmer who owned our house until the 1960s only travelled as far as the coast, barely ten miles away, twice in his life).  How did a French coin from the 1850s end up "lost" in a field here?

I have thought about getting a metal detector to see what I can find, but I know that so much household and farm waste has just been dumped everywhere until the mid 1980s that I'd be most likely to find bits of scrap that someone had buried in a hole just to get rid of it.

James

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I've just been out to check the view over the house at the moment.  The Moon is clearly visible and Jupiter is pretty much at the roof ridge height, so I think the house should only block no more than twenty degrees above the horizon.  I won't be able to see some of the Messier objects in Scorpius, but I think I can live with that.

James

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1 hour ago, Uplooker said:

Great start James, I will follow progress with interest.

It feels very positive to have started.  I think I've been promising myself this since my son was nine or ten and he's just turned fifteen ?

I suspect it's going to be quite a long journey.  I have someone lined up to make the piers though he's apparently a bit busy fixing farm implements at the moment and doesn't reckon he'll have much time for the next month.  He has a good reputation, but I'm still not sure I want to pour the concrete for the pier bases until I have the actual metalwork to line up the mountings.  I know I could provide him with a jig with the actual hole positions, but working in IT for thirty years very much gives you the mentality that "if it can go wrong, it will go wrong".  And whilst I can easily get power from the "beer shack", I really ought to upgrade the cable between there and the house and provide a proper earth.  I want to run hard-wired networking from the house too as the wifi connection I have to the beer shack at the moment is a bit hit-and-miss.

If I'm in by the time the clocks go back, I shall be very happy.  As will my wife, who will no longer have astronomy gear cluttering up the house.

James

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Good luck James ?  I thought my observatory site was steep but yours is worse!  Mine is much the same size though the warm room takes more of the area.  Mine is also on 6 concrete blocks.  With hindsight (wonderful thing!) I should have built my scope room bigger with two piers (or more).  Swapping heavy scopes is a nuisance.  But my widefield imaging is moving outside the main observatory onto a Skywatcher Pillar Mount with DIY fork mount and DIY 3D printed mini dome.  So I too am building a new observatory but on a tiny scale ?

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Glad to see you are finally getting around to this build, it has been a long time a coming.    Quite a challenging site for a build, but will be good to have a raised deck/base as the floor, which should keep you and the equipment safe from any flood waters.    I'm sure that West Country builders built the shed square and the dry stone wall is still standing, so blaming camera distortion.     Are you rolling the roof off uphill towards the house, or going for extra long legs on the downhill end and does this affect the warm room?   Hope you get the time and weather to enjoy the build and some clear skies this autumn and winter to sit back and enjoy the views.

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Good luck mate, I’m now re starting my obsy build after taking the original down. Just some quick advice For this build would be take your time you’re waited along time for this and it will probably cost more than you plan. I built a great observatory (ROR) and then made all my mistakes on the connections and internal layout part. Cheap cables are not your friend,forget any kind of usb repeater cables and if your going to have a pc permanently set up in the obsy keep it as close to the pier and mount as possible to avoid long cable runs. USB hubs are a pain so if you have to have one spend the money on a decent one that’s powered (Startech). Please don’t think I. Being negative just I had to learn the hard way and like yourself I waited along while to build an obsy only to be disappointed because I tried to cut corners on the budget when it came to the connections. Again good luck and I look forward to seeing this progress.?

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1 hour ago, Gina said:

Good luck James ?  I thought my observatory site was steep but yours is worse!  Mine is much the same size though the warm room takes more of the area.  Mine is also on 6 concrete blocks.  With hindsight (wonderful thing!) I should have built my scope room bigger with two piers (or more).  Swapping heavy scopes is a nuisance.  But my widefield imaging is moving outside the main observatory onto a Skywatcher Pillar Mount with DIY fork mount and DIY 3D printed mini dome.  So I too am building a new observatory but on a tiny scale ?

I was tempted to make the warm room larger, but when I actually looked at how much space I use when I'm working day-to-day it's not a huge amount so I'm hoping that what I've planned will be sufficient.  It's quite possible that I won't have the main door entering the warm room which should free up some space.  It all comes down to the wall height really, though given how low the doors are on some commercial observatories perhaps that shouldn't be such a worry :)

James

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1 hour ago, SnakeyJ said:

Glad to see you are finally getting around to this build, it has been a long time a coming.    Quite a challenging site for a build, but will be good to have a raised deck/base as the floor, which should keep you and the equipment safe from any flood waters.    I'm sure that West Country builders built the shed square and the dry stone wall is still standing, so blaming camera distortion.     Are you rolling the roof off uphill towards the house, or going for extra long legs on the downhill end and does this affect the warm room?   Hope you get the time and weather to enjoy the build and some clear skies this autumn and winter to sit back and enjoy the views.

Thanks Jake.  The plan is to have the roof roll off over the top of the warm room with higher legs to support the rails.  I did consider having it roll the other way, but it seemed logical to have the roof roll away from the southern end where it won't obstruct the view.  Having it roll that way also means I don't have to think about how to get a decent seal between the rolling section of the roof and the warm room roof.  There are advantages to going the other way though, so I might change my mind yet :)

James

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My warm room is far larger than I need or even want.  In fact I'm considering converting it to a summerhouse, making it dual purpose ?  When I built the observatory several years ago many things were different.  Nowadays, I control everything (except the roof) from indoors and the astro control has gone from desktop PC to laptop and now to Raspberry Pi on the pier.  Only the main power supply and backup battery remain in the warm room and they could be moved to the scope room if I wanted - onto a shelf.  ATM the warm room is just another place to collect rubbish ?

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After some thought I have decided to lower the two pads I have already constructed shuttering for so I can reduce the height of the north east end.  When I make up the ground later I'll make sure it doesn't come right up to the top of the pad.  I intended to put some DPC material between the timber and the pad anyhow, so that should protect it from damp.

James

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Thanks for the plug to my build James ?.   Really interested to see how yours develops.

I spent ages battling with wall and pillar heights to try and get the best horizons without needing to stand on top of a step ladder! At the end of the day it's often a compromise I think. I'm still not sure I've got mine right, and am already thinking about whether to put an extension on my concrete pier. My design is based around a large-ish Newtonian with a high eyepiece position, but I'm now likely to be using a frac, and possibly an SC if funds allow, so I'm now likely to be grovelling on the floor to access the eyepiece!

Lovely part of the country you're in and I imagine you get some pretty dark skies. You've got loads of space there which I'm very envious of.

My maternal family hail from down your way (Yeovil/Chard), so I know what you mean about it being an historically poor area. All my family were ag-labs with no fame or fortune that I've so far been able to discover!

Will be following your build with interest. I pass your way regularly to visit my daughter at Falmouth Uni, so if you need a pair of hands for some grunt-work just let me know!

Kev

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Thanks for all your comments and offer of assistance, Kev ?

Perhaps I should err on the side of caution once I get to working out pier heights and choose something that can be relatively easily made higher with an extension rather than going for something high and then finding that it needs to be lower.  Once I have the floor height sorted and can position a few things to test them out then I'll see how things go.

I was hoping to get more of the shuttering sorted this evening but after three hours on poolside this evening, much of it with a group of not entirely enthusiastic teenage swimmers, I just haven't got the energy any more so it will have to wait until tomorrow.

James

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17 minutes ago, JamesF said:

Thanks for all your comments and offer of assistance, Kev ?

Perhaps I should err on the side of caution once I get to working out pier heights and choose something that can be relatively easily made higher with an extension rather than going for something high and then finding that it needs to be lower.  Once I have the floor height sorted and can position a few things to test them out then I'll see how things go.

I was hoping to get more of the shuttering sorted this evening but after three hours on poolside this evening, much of it with a group of not entirely enthusiastic teenage swimmers, I just haven't got the energy any more so it will have to wait until tomorrow.

James

For what it's worth James, I used SketchUp to model pier/wall heights etc. It has useful angle measuring functionality in addition to it being a great drawing tool. I found it invaluable (although until the scope is actually mounted on the pier, perhaps I shouldn't say that just yet!).

Edited by Astrokev
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That sounds like a good plan.  Perhaps I should start that this evening.  I did my original obsy design in Sketchup (scarily, looking at the file dates that was in August 2011!)  Quite possibly I need to remind myself how to use Sketchup anyhow, what with the 3D printer project that is coming over the summer.

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Well, I have the skeleton of the walls and floor in place in Sketchup, having spent a bit of time in the small hours remembering how to drive it.  Problem is that's tempted me to see if I can fit in three piers ?  The options are to have them in a straight line down the middle or move them off-centre, two on one side and one on the other.  Could be a little snug in places, but I'm thinking I only really want one for occasional observing as most of the time for visual I'd get the 10" dob out, so if there's not so much space around the other two then cameras don't exactly take up a great deal of space...

I just can't help myself, really.  This happens every time we start something.  When we had the cellar made habitable earlier this year the old stairs had to come out because they were rotten and I found myself thinking "a spiral staircase would look really nice there".  And as some of the utility room ceiling had to be taken down due to damage from the recent leak I suggested we could get all the lighting sorted in there as it's never been quite what we wanted.  Everything seems to turn into an opportunity to do something more complicated ?

My epitaph will be "He could always turn two hours DIY on a Saturday morning into a month-long project"

James

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This is what I've been playing with this evening ?

obsy1.png

The pier centres are at least 800mm from the walls and no closer to each other than 1300mm.  South is pretty much at the top.

The walls are 1500mm high and as best I can measure the angle from the DEC axis to the south top corner is about 25 degrees, and about 32 degrees to the closest part of the wall.  I think that's workable, though I might lower the walls a little more.  The piers are 1200mm high, 900mm of which is above the floor height.  I could lift the height of the piers a little instead of lowering the walls, though the advantage of having 300mm below the floor is that there's room to get to the bolts from underneath should it be required later.  Or I could just make the piers taller.  Whichever way I think I'll need a drop-down flap on the south west end as there won't be clearance over the telescopes otherwise.

If I don't use this layout then I'll probably drop back to a two-pier design with the piers on the diagonal to get the best spacing between them.

James

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