7Wells Observatory Build

[JamesF]

35 minutes ago, Astrokev said:

I must try that if I can't download the free version

https://www.sketchup.com/sketchup/2017/en/sketchupmake-2017-2-2555-90782-en-x64-exe

Any good to you?  Or

https://www.sketchup.com/sketchup/2017/en/sketchupmake-2017-3-116-90851-en-dmg

for MacOS.

[Astrokev]

16 minutes ago, JamesF said:

https://www.sketchup.com/sketchup/2017/en/sketchupmake-2017-2-2555-90782-en-x64-exe

Any good to you?  Or

https://www.sketchup.com/sketchup/2017/en/sketchupmake-2017-3-116-90851-en-dmg

for MacOS.

great, thanks James. I'll give it a try  

[laser_jock99]

On 08/04/2019 at 20:54, old_eyes said:

I am thinking of using polyester coated corrugated steel as the cladding for as much as possible - I like the low maintenance aspects and it fits with the rural environment. There are sheds like that all over the place! Not sure of cladding for the asreas where the roof runs as corrugated steel would stick out too much. Possible half-timbered?

Any immediate thoughts, particularly looking for the stupid mistakes that more experienced eyes immediately spot.

Cheers!

I used plastic coated, galvanised steel cladding on my obsy build- dark green to blend into the landscape. It seems to have weathered the storms okay and to be honest looks as good now as the day we put it up- no rust or detoioration to the finish. I'm in the process of planning another shed with same material.

Timber frame

 

Dark green, sheet metal walls fitted to frame.

 

Finshed off the two visible sides in waney edge pine cladding.

[old_eyes]

 

 

 

2

15 hours ago, laser_jock99 said:

I used plastic coated, galvanised steel cladding on my obsy build- dark green to blend into the landscape. It seems to have weathered the storms okay and to be honest looks as good now as the day we put it up- no rust or deterioration to the finish. I'm in the process of planning another shed with same material.

 

I think it might have been your build that set me off on the corrugated steel idea. It is a lovely structure. As you say, maintenance free and looks like loads of other stuff in a rural landscape. I had forgotten, or not noticed, the timber cladding; presumably on the house/garden side.

In my design, I have the roof sitting over the warm room to allow for lower side walls, and to try to avoid possible equipment clashes. The problem then is I have certain areas to clad where the corrugations would stick out too much and I need something flatter. Timber might do the job nicely.

[laser_jock99]

5 hours ago, old_eyes said:

In my design, I have the roof sitting over the warm room to allow for lower side walls,

I got round the need for having lower side walls by parking the scope in the 'upside down' position- I think I'm unique in doing this!

[old_eyes]

OK. Having listened to everyone's advice, the current design looks like this:

I have raised the height of the side walls to 1.5m, and put the necessary 1:40 rake on the roofline. Raised the pier height slightly to maintain reasonable horizons, which helps with the view to the North over the warmroom. I experimented with reducing the size of the warmroom to get better horizons, but within the agreed footprint, you don't gain much horizon and lose a lot of warmroom. Tan(theta) is not your friend.

 Added an outward opening narrow door to the rear of the warmroom and a sliding door between warmroom and telescope area. 

Simple hinged end flap that will in some way be locked to the roof and weatherproofed to stop rain getting in. Moved the rails up to just below the wall height to shorten side members of the roof structure. F H Brundle v-groove wheels now intended to go inside the rood frame so that the frame comes out to the edge of the rails allowing a cladding overlap to further weatherproof.

Roof only just clears the expected position of current imaging scope, so if I go for a longer OTA, future remote operation could be a problem. I can always lower the side walls again once I have spoken to my metal frame fabricator friend.

I plan the bulk of the cladding to be coated corrugated steel as with the @laser_jock99 build.

Couple of specific questions:

With F H Brundle v-groove wheels, do they come with a ball race, and what size of bolt should be used to secure them?

I am planning to run ethernet to the observatory in the same trench as the power. I had assumed that common mode rejection would be good with cat6 and I could just bung it in the same trench, but I have read a number of comments from electrical engineers that you need 300mm separation. I am pretty sure nobody has mentioned that on this forum, so wondered what the practical experience was. We haven't got a lot of noisy stuff connected to the power so I had hoped everything would be pretty quiet.

All advice and thoughts gratefully received!

[JamesF]

Looks good.

The V-groove wheels come in a variety of sizes and styles, but not all of them have a ball race as far as I'm aware.  Some also come already fitted into a bracket for mounting.  It's probably worth a browse around their site to find the design that works for you:

https://www.fhbrundle.co.uk/groups/13SWV__V_Groove

How big/long a trench were you planning for the power?

James

 

[laser_jock99]

Looking good so far.

If you stretch the budget to use armoured mains cable- then the metal shielding will surpress any RFI coming out of it.

https://uk.rs-online.com/web/p/products/0379126/?grossPrice=Y&cm_mmc=UK-PLA-DS3A-_-google-_-PLA_UK_EN_Cables_And_Wires-_-Electrical_Power_And_Industrial_Cable|Sy_Cable-_-PRODUCT_GROUP&matchtype=&pla-394215423796&s_kwcid=AL!7457!3!243856868087!!!g!394215423796!&gclid=EAIaIQobChMImZvJmJzu4QIV1ITVCh2bPwzwEAQYAyABEgLrXvD_BwE&gclsrc=aw.ds

It would be better for burying and more resistant to rodent attack too (a big problem for me).

 

[old_eyes]

@laser_jock99 trench is about 65m. Yes cable will definitely be armoured SWA.

[old_eyes]

1 hour ago, JamesF said:

Looks good.

The V-groove wheels come in a variety of sizes and styles, but not all of them have a ball race as far as I'm aware.  Some also come already fitted into a bracket for mounting.  It's probably worth a browse around their site to find the design that works for you:

https://www.fhbrundle.co.uk/groups/13SWV__V_Groove

How big/long a trench were you planning for the power?

James

 

It’s quite difficult to work out which wheels have ball races, and there aren’t dimensioning diagrams for all. I saw the caged version, but it doesn’t fit the metal roof frame I am planning. Trench is 65 m.

[JamesF]

3 hours ago, laser_jock99 said:

If you stretch the budget to use armoured mains cable- then the metal shielding will surpress any RFI coming out of it.

That was my thinking, too.

James

[Gina]

Yup!

[old_eyes]

Okay - after a visit from my son and daughter-in-law who live in California, it is back to work.

Following discussions over placement with my gardening and wildlife conserving wife, we decided to shift the proposed location away from the middle of the field to the side against a hedge.

This has the advantage that the trees to the south are less obtrusive and the hedge to the north is something I can deal with myself without heavy machinery.

This diagram shows the current angle to the horizon in blue, and the limiting angle created by the observatory walls and roof in orange.

 

The spike in the landscape to the NE is a dirty great Sycamore that I might or might not have the energy to deal with (I hate Sycamores!). The stuff from W round to N is mostly hedge that could be reduced to a horizon of about 20 deg without too much effort. The large trees to the S have pretty much been taken out of the equation.

I could reduce the height of the warm room to improve the view to the N, but is it really worth it. It would mean taking the warm room from something I can reasonably stand in to something which is a perpetual crouch. I am inclined to say that is good enough, but if anyone thinks differently, shout!

In the meantime, stuff is starting to arrive, so I need to get on with things.

These are the cables and conduit for power and ethernet. Waiting for the trenching people to confirm a date to dig a 70 metre run.

[old_eyes]

Took a few days off to break ground on the observatory, only to be hit with torrential and persistant rain. I think it is the observatory building equivalent of the permanent cloud setting in when you have just taken delivery of a new scope, camera, eyepiece or whatever.

So have had to write-off this week and hope for a chance again in a couple of weeks 

[old_eyes]

Actually made a start.

I am now the proud possessor of a lot of wood:

And courtesy of my builder neighbour a large hole:

Conreting tomorrow after we have finished the shuttering, but first I will have to bail out the hole. When you sit on the spring line, holes do tend to fill up!

Anyway, things actually happening which is very exciting.

Edited June 27, 2019 by old_eyes

[JamesF]

Digging holes is such much easier when you have the right tools for doing it

James

[Swoop1]

1 hour ago, JamesF said:

Digging holes is such much easier when you have the right tools for doing it

James

I find it is better to have someone else with the right tools.....

[Gina]

But they might not dig it right.  Might be round instead of square, want it here and they dig it there...  etc... 

[JamesF]

11 minutes ago, Gina said:

But they might not dig it right.  Might be round instead of square, want it here and they dig it there...  etc... 

And we know what happens to people who complain about that sort of thing

James

[old_eyes]

8 hours ago, Gina said:

But they might not dig it right.  Might be round instead of square, want it here and they dig it there...  etc... 

Now THAT is going back a ways! The wonderful Bernard Cribbins. Along with “Right said Fred” the soundtrack of my youth.

[Gina]

Yes indeed.

[Swoop1]

So we had a cup of tea.........

[old_eyes]

Next step - pouring the pier block

And sinkthe bolts for the pier.

All I have to do is wait a week now. This will be difficult. I could never obey the instruction "wait until the glue is fully dry befrore the next step" in Airfix models.

The hole was slightly bigger than originally planned so took almost a tonne of sand and gravel.

[JamesF]

Good stuff :)

James

[laser_jock99]

Good to see some progress.