Astrokev's Obsy Build

[Gina]

If you built your obsy E-W with the scope room facing east, you could have a flap at the top of the wall to lower down and give yourself a better view to the east. That's what I did (though I went further and had some of the wall as part of the ROR). BTW I did a similar thing in measuring the viewing angle restrictions presented by trees and buildings with entry of the info into SketchUp.

[Gina]

If you built your obsy E-W with the scope room facing east, you could have a flap at the top of the wall to lower down and give yourself a better view to the east. That's what I did (though I went further and had some of the wall as part of the ROR). BTW I did a similar thing in measuring the viewing angle restrictions presented by trees and buildings with entry of the info into SketchUp.

[jambouk]

You've measured your angles well, i just used fists held at arms length yesterday when i was working out my visual horizon in a 360 panorama:

[Bizibilder]

I would certainly recommend having the walls high enough to block any neighbours lights - It's amazing just how many folk leave the lights on all night! If you have any streetlights to contend with then make sure they are blocked too. My own Obsy is positioned so that two streetlights ar blocked by houses and, having been so careful to get that right, the council now turns them off at midnight!!

[Astrokev]

If you built your obsy E-W with the scope room facing east, you could have a flap at the top of the wall to lower down and give yourself a better view to the east. That's what I did (though I went further and had some of the wall as part of the ROR). BTW I did a similar thing in measuring the viewing angle restrictions presented by trees and buildings with entry of the info into SketchUp.

Thanks Gina. That's a good idea, but I really want to keep the observatory with it's longest axis parallel to the fence to the west, with the ROR rolling to the north. This is to keep as much of the lawned area as clear as possible. My wife has been very kind in letting me build the thing at all, so I don't want to push my luck there . As Malcolm has suggested, I could always make a drop down wall to the east, which is the same principle as your suggestion, but a bit more design work.

I think I've got all the information I need now to start serious design. Just need a bit of time. We're in the middle of a house extension project at the moment and am also having to make-up a load of flat-pack kitchen cabinets which is also eating into my time!

[Astrokev]

I would certainly recommend having the walls high enough to block any neighbours lights - It's amazing just how many folk leave the lights on all night! If you have any streetlights to contend with then make sure they are blocked too. My own Obsy is positioned so that two streetlights ar blocked by houses and, having been so careful to get that right, the council now turns them off at midnight!!

Hi Roger,

Good idea. Fortunately our village doesn't have any street lights, and we only have one neighbouring house that we can see from our back garden (visible in the panorama shots I posted) which doesn't tend to interfere too much at all. However, the biggest problem is a decorative lantern which is just the other side of the fence behind my tool shed (the brown shed, not the white one, which is on the corner of another neighbours driveway). This is a real pain! Since it's so close to our boundary, I was thinking that I may be able to make some kind of shield at the end of a pole that I could push over the fence to block the light when I'm out observing. I'll have to give this some thought.

[yesyes]

We're in the middle of a house extension project at the moment ....

perfect, so you have all the building tools on site now? I would make use of that and get at least the foundation and pier done while you have a concrete mixer and so on...

[Astrokev]

That's a cracking idea Chris! Unfortunately, the main building work is finished, although the mixer is still sat on the front lawn. I'll have to get a move on to finish the design and hope that it's still here, in which case I'll speak kindly to the builder. That would save me quite a lot - hire costs are pretty steep these days. I've also been keeping an eye out and have been pulling bits and pieces out of the skip that I thought might be useful. So far, I've reclaimed a pile of bricks that I intend to use in the pier base and to fill the pier, to help the concrete stretch a bit further; a few building blocks that I'm thinking of using to help make the low wall for the base ("borrowed" from Malc-c's design), and a fair amount of 4" Xtratherm wall insulation panels for the warm room. Every little helps. Just a shame our house is being clad with tongue and groove cladding!

[Gina]

What's wrong with T&G cladding on your obsy? Match the house as well

[Astrokev]

What's wrong with T&G cladding on your obsy? Match the house as well

Oops. Typo on my part there Gina. It should've read "Just a shame our house is NOT being clad in tongue and groove cladding!" Sadly, the extension is standard bricks and mortar!

[Gina]

Ah yes - I did wonder

[Astrokev]

For the main wall frames, I'm wondering what size timber to use. I'm currently looking at 38 x 89mm studding. Would this be OK?

Thanks

[badgerchap]

Looking good there

[Gina]

For the main wall frames, I'm wondering what size timber to use. I'm currently looking at 38 x 89mm studding. Would this be OK?

Thanks

Well adequate I should say I used 47 x 75mm for my framework - with around 45mm spacing.

[Digz]

2x3's, as Gina suggests should be more than sufficient. Just remember that you need to add horizontal noggings between each stud at about halfway up the stud to help strengthen it and reduce the desire for the stud to want to twist.

[malc-c]

I used standard stud work 38mm x 63mm from Wickes on 400mm centres. However of the 110 lengths I purchased on line a good 15% were of poor quality (warped or twisted) so if you go down that route it's worth taking the time to personally select each length as Wayne did in his build. The alternative is 2" x 3" on 450mm centres as Gina and Lee have suggested. I would also add that fitting diagonal braces here and there will really improve the sturdiness of the framework.

[fwm891]

Kev, Not sure just how far down the line you are with the design/build at the moment. What I did was to build a small scale model (weather was bad so couldn't do much else) from my design just to make sure everything fitted as I had a very limited space to place the obsy.

Posts #35 and #39 in this thread:

The final job was done with a great deal more confidence (still need to do a final paint job....)

[Digz]

Cant beat a bit of model making to test designs before real world manufacture!

[Astrokev]

Kev, Not sure just how far down the line you are with the design/build at the moment. What I did was to build a small scale model (weather was bad so couldn't do much else) from my design just to make sure everything fitted as I had a very limited space to place the obsy.

Posts #35 and #39 in this thread: http://stargazerslou...20#entry1586534

The final job was done with a great deal more confidence (still need to do a final paint job....)

Great models! I had considered trying to make a model but, if I'm honest, I'm not sure it would add much value (for me anyway) to what can be achieved in Sketchup. That said, the challenge of making an accurate scaled model must be very satisfying!

[fwm891]

Kev, I made a model because I had a very tight site (6x6 ft approx), I had the mount and the scope so it was easy to measure everything on a tripod to get the balance points, turning circles etc (remember the dew shield) and made a model to suit.

The NEQ6 and MN190 + accessories all fit quite nicely in the 1.8 x 1.8 metre interior dimensions. I don't have a warm room attached to the obsy but run cables a short distance to the conservatory. Now things are drying out well I'll paint the exterior. It just got left as treated timbers last year after the build.

Good luck

[Astrokev]

I'm really struggling with planning the wall and pier height to enable me to be adequately shielded from the wind and elements, whilst also giving reasonable low altitude views, whilst also giving adequate ceiling height in the warm room - a common problem I know.

If the walls are high I get good headroom and wind protection...but I can't see anything

If the walls are low I get good views but am exposed to the wind and have to stoop to get in the warm room

Two options have occurred to me -

1. Have high walls and make drop down panels to the south and/or the east (as done by some other builders) = good headroom, protection and views.

2. Have a split level floor, with the scope room floor being raised. This would be a bit of a compromise but would give good warm room headroom, and reasonable views & protection, without the need to make drop walls.

Has anyone considered Option 2 or tried this approach? Would it work d'you think?

Something like this -

[r3i]

I'm really struggling with planning the wall and pier height to enable me to be adequately shielded from the wind and elements, whilst also giving reasonable low altitude views, whilst also giving adequate ceiling height in the warm room - a common problem I know.

If the walls are high I get good headroom and wind protection...but I can't see anything

If the walls are low I get good views but am exposed to the wind and have to stoop to get in the warm room

Two options have occurred to me -

1. Have high walls and make drop down panels to the south and/or the east (as done by some other builders) = good headroom, protection and views.

2. Have a split level floor, with the scope room floor being raised. This would be a bit of a compromise but would give good warm room headroom, and reasonable views & protection, without the need to make drop walls.

I guess a decision should also take into account the height of the folks who'll be regularly using the observatory. For once being vertically challenged worked in my favour so I have got away with 1.8m tall walls in both the scope and warm rooms (though the pitched roof and casters etc. on the scope room roof mean there's a lot more head room in there).

I went for a fold down flap on the end (South East) wall and this has worked well for the occasions when I've wanted to see right down to the horizon (recently Saturn and the Moon for example). The 1.8m walls have given good wind protection as it gets a bit breezy here from time to time.

Deciding on the best wall height does take a good bit of thinking about

[fondofchips]

I guess a decision should also take into account the height of the folks who'll be regularly using the observatory. For once being vertically challenged worked in my favour so I have got away with 1.8m tall walls in both the scope and warm rooms (though the pitched roof and casters etc. on the scope room roof mean there's a lot more head room in there).

I went for a fold down flap on the end (South East) wall and this has worked well for the occasions when I've wanted to see right down to the horizon (recently Saturn and the Moon for example). The 1.8m walls have given good wind protection as it gets a bit breezy here from time to time.

Deciding on the best wall height does take a good bit of thinking about

I've thought about the wall & pier height & my shed builder has told me the walls will be 6' 6" (2.03 metres) high. Concreting in the pier mount isn't easy to get to an exact measurement so I've opted to work out the pier height AFTER the shed is erected. Then I will use the EQ5 mount & tripod to work out how high the pier needs to be, hopefully using an observing session to work out the height as close as possible. My friend who is making the pier has already obtained the materials so there should not be too long a delay before I get my pier. If anybody has a better way of working out the relationship between wall height & pier height I would like to hear it.

[Bizibilder]

I think we all put far too much emphasis on being able to see as close to the horizon as possible. In the UK it is often very murky at anything below 20° elevation and we have the advantage that things "rotate" into view quite conveniently. I accept that a good southern veiw is really helpful but it is not the end of the world if you don't - my own view south is blocked by two large trees (that belong to two different neighbours).

After using my own observatory for three years I am now in the process of a rebuild and upgrade and I intend to raise the wall height by 6" in order to allow more room inside for both the scope and myself.

The only times that I have really needed lower walls is for viewing the Sun when I come in from work in March and September - I have got around this by having a semi-portable EQ5 on a pier, this can be positioned to "extend" my Solar viewing season. I also miss out on Mercury and Venus (sometimes) but even lowering the walls by a foot would make little difference as the view is blocked by houses.

I do wish I had a better southern view - but when I built the observatory I knew the trees would block part of my view no matter where I placed it.

[malc-c]

Have to agree with Roger, unless you have perfect southern skies right down to the horizon clear of light pollution then there is no need to get hung up on trying to achieve views of less than 20 degrees.

I looked at a split level scope / warm room, but having a step up is one more hazard to worry about in the dark. It can also lead to lower head room in the scope room or low head room through the opening between both rooms. I guess it all depends on your physical height. If you are 6' 10" then that is going to be the min head room for the warm room walls as you would otherwise have to stoop. One possibility in that case would be to dig out the foundations so that the floor is a foot or so below ground level. But this will generate its own issues in trying to damp proof the structure.

Often a permanent set up in an observatory is a compromise. For me anything low in the west or north is out, mainly due to trees and the fact I didn't incorporate a drop down flap in that side wall, as I thought it might weaken the structure too much. This meant that observing / imaging things like the recent comet was a challenge. But then having the ability to be up and running in a matter of minutes with all the other benefits having an observatory gives outweigh the limitations it has