North Kent Roll Off Roof Build

[Naughty Neal]

The 4 x 2  slide off rails will need beefing up  or replacing with something far sturdier to prevent sag/bowing,  one  could add an additional central support post on both sides. 

 

Edited May 15, 2023 by Naughty Neal

[malc-c]

I agree, the wood used to support the roll off roof needs to be  a little more substantial, or the existing supported by some cross-bracing.  Other than that I think you've done a fantastic job.  

[Graeme]

4 hours ago, Naughty Neal said:

The 4 x 2  slide off rails will need beefing up  or replacing with something far sturdier to prevent sag/bowing,  one  could add an additional central support post on both sides. 

 

3 hours ago, malc-c said:

I agree, the wood used to support the roll off roof needs to be  a little more substantial, or the existing supported by some cross-bracing.  Other than that I think you've done a fantastic job.  

 

Thanks for the input. You're both right of course, I didn't appreciate the total weight of the roof once all the OSB and roof felt was added! The calculation I did to work out the weight required under the legs to mitigate against the risk of wind lifting the roof when rolled off was done quite recently, after I added together the weight of all the component parts. And even then I thought the angle iron would stiffen the 4 x 2 adequately. Probably should have gone for 5mm angle iron but that adds a level of difficulty to the construction. 3mm angle iron is easier to work with but a lot more bendy than I imagined! So the plan now is to put in additional 4 x 2s to the underside of the two that are there now and add two diagonal braces to each one. 

Graeme

 

[Naughty Neal]

It will be better if adding another 4 x 2 , to do so by having it on edge to form a T section beam  plus the bracing for  rigidity.

 

Edited May 15, 2023 by Naughty Neal

[Graeme]

1 hour ago, Naughty Neal said:

It will be better if adding another 4 x 2 , to do so by having it on edge to form a T section beam  plus the bracing for  rigidity.

 

Hello NN. 

I did consider turning the support beams from horizontal to vertical for rigidity but decided to keep them the same as the other timbers. Good job I did now that the steels need most of the width to remain parallel.  I like your T section idea, cheers.

Graeme

[malc-c]

Graeme,  any length of timber used as a beam will be able to support more if used vertically due to the grain structure.  Ideally the beam should be placed on top of the two posts so that the weight gets transferred through the posts (like a compressive force).  If you place the beam between the posts then you are reliant on the screws or bolts taking the weight.  Diagonal bracing will help tie thing together if it's impossible to make these changes at this stage.  Neal's suggestion of turning the existing beam into a T beam by using a 4" x 2" is a good idea.  You could go one step further and add a second beam identical to the existing to for an I beam.  Use a decent waterproof adhesive between the beams and secure with screws every 12-18".

Granted this may seem overkill, especially as they only support the roof when the observatory is in use, but over time the weight could cause the beam to sag and cause problems, so having a belt and braces approach and over engineering things is the best method 

[Graeme]

Thanks for that Malc. Your input is appreciated.  I would agree with all that you are saying. The beams are sitting on a noggin fixed to the post rather than just hanging off the screws because I wanted to get the posts in, concrete cured ready to go before I cut the posts to height so as to allow the beams to be fixed at a perfect horizontal. So they are held with 4 x 3" x 12s at each end in total. 

I think my way forward is to put in two more 4 x 2s to double the thickness of the beams and 4 x diagonal braces to support them and crack on! That should suffice. My first priority is to get the thing up and running so that I can do some astrophotography, it's been a long time! I can monitor the cross beams each time the roof is opened and if I do get some sag in the future I'll add two more uprights. 

Graeme

 

[malc-c]

No problem.  What you have sounds fine, and it's not really going to need "upgrading" immediately.

Lets hope for some clear skies so you can christen the thing 🙂

 

 

[Naughty Neal]

Modern  building design  use T Beams in flooring design now to save weight and costly solid timber joists  , typically a top timber 3 x 2 for example is grooved and a osb board of what ever depth is needed for the span calcs to work are glued in place to maks up  beam.

[Graeme]

I've put in four more diagonal supports under the roof roll off timbers and they're fixed with 6" x 5mm screws. That should do for now!

And I've put the floor subframe in today. Can't put the floor down yet till I've done the air bricks, put a conduit in for a light switch and done a final check for water ingress after it rains.

It's not going to rain tonight, in fact it's forecast clear, So I've set up the mount, the telescope and the lap top. I'm going to have a go at M101 and see if I can capture an image of the supernova that was spotted yesterday. And if it's clear tomorrow too, I'll get some more data, because I can now I've got an observatory!

Graeme

 

Edited May 20, 2023 by Graeme

[Graeme]

Partially successful! The camera failed to download a couple of times and I had to disconnect and re-connect to get it going again. The guiding didn't display an image probably because I didn't focus it in daylight like you're supposed to do! And I didn't seem to be able to focus it in the dark. As a result I wasn't able to guide and was limited to 60 second exposures. But I'm still claiming this as a win since the aim was to set up, polar align, test everything and capture an image of the supernova in M101. I'll have a look today to see if the trees in the distance that I used previously for day time focusing are still visible over my observatory wall.

In the meantime, here's my observatory first light image, single frame, 60 seconds, unprocessed, M101, SN2023ixf:

 

Edited May 21, 2023 by Graeme

[whipdry]

Focusing a guide camera at night shouldn't be a problem, just keep doubling exposure time until you see something to work with... if that fails try using the moon! 

I'll finish with a word of warning once you have the obs sessions up & running tweaking things can become the obsession!

Peter

[Graeme]

2 hours ago, whipdry said:

Focusing a guide camera at night shouldn't be a problem,

Thanks Peter, I've always managed it before now but matching the guide camera focus to the main camera focus when using an OAG is a lot easier during the day. I had a look at it today but the trees in the distance that I used before are no longer visible due to the observatory wall! I could take the OTA off the mount and bring it out where it can see the trees but I'll probably just keep going out to the observatory and tweaking it some more!  😀

Graeme

[Graeme]

And here's my processed observatory first light image:

 

 

64 x 60 second subs, 10 darks, 30 flats, 30 dark flats. Captured with NINA. Stacked and Processed in Pixinsight.

Not bad for an unguided image but I probably need to watch some more processing videos! It's been too long!

Graeme

[Graeme]

Well that's the outside all done! I used the remainder of the roofing felt to cover the gable ends. I think it works but not sure if I like the roofing tac nail heads, it might need some sort of trim around the edge. But for now I need to crack on! Using a different type of wood on the last strip at the top of the walls might have been an error, probably should have got some more feather edge boards and cut them to fit. Then I would have got a better colour match. I've knocked out the bricks for the air vents but I need some sort of anti spider mesh before the vents goes in. I must do something about that gap at the end of the angle iron when the roof is open, but that can wait for now.

 

 

 

Need to crack on with the inside now!

Graeme

 

[Graeme]

Got a floor now! Got a temporary table too which will get replaced by a fixed desk. But I can get up and running with the laptop.

I need to get the mains cable and Cat 5 cables in from the garage next. 

 

 

I've got a pier that's sprayed black, a mounted mount with a telescope on it and it's a clear night tonight! 

 

 

Shame about the Moon!

 

 

[Graeme]

The cables are pulled into the pipes and the pipes are boxed in. I fitted a desk which matches the drawers, made out of the same G Plan teak, veneer wood. If it's clear tonight I'll be setting up the guiding. If it's cloudy I'll re-do my darks library.

[Naughty Neal]

It's looking good Graeme , but for me it is too techy .  Techy is stuff I don't really understand , one reason why I don't have a hand hed phone.

[Graeme]

7 hours ago, Naughty Neal said:

It's looking good Graeme , but for me it is too techy .  Techy is stuff I don't really understand , one reason why I don't have a hand hed phone.

Cheers Neal

I love a bit of techy!

 

Edit: Also, the flat frame light box is not too techy, it's left over white LEDs, cardboard and duct tape covered in some A1 white paper!

Graeme

Edited June 18, 2023 by Graeme
Addition of non techy item description!

[LongJohn54]

Don't worry about your roof runners and supports, they look plenty strong enough.  Mine are 3 x 2 timber (horizontal) each backed up with two strips of 1 inch angle iron which makes for a very lightweight construction.  My roof weighs about 220Kg and I stand on it when opened (another 95kg) to trim back next doors leylandi. Eight years on and they are still straight and level.

Your obsy looks great. 👍

 

 

[Graeme]

9 hours ago, LongJohn54 said:

Don't worry about your roof runners and supports, they look plenty strong enough.  Mine are 3 x 2 timber (horizontal) each backed up with two strips of 1 inch angle iron which makes for a very lightweight construction.  My roof weighs about 220Kg and I stand on it when opened (another 95kg) to trim back next doors leylandi. Eight years on and they are still straight and level.

Your obsy looks great. 👍

 

 

Thanks Long John.

I hope my build lasts as long, 8 years should see me out! 

Graeme

[adyj1]

(I posted this info earlier to a different thread in reply to a comment by Greame, but I think it probably belongs here)

I followed astrobloke-and-joe's ROR guide (with a few tweaks) with this motor from Amazon (currently £140,got it pre-pandemic for just over £100)

CO-Z Electronic Gate Opener Kit Automatic Sliding Gate Opener for Gate Up to 600KG 200W Gate Opener Motor with 8 Gear Racks and Remote Controls (200W)

(and a follow-up post on that thread);

 

Ah, Mr Heath! Meet Mr Robinson 😆

(the other end of the 'shelf' on which the motor sits is attached to an adjacent shed just out of shot.)

My top tip was to use galvanised steel cable channelling (95p/m) to guide the roof along the beams, rather than the very expensive heavy duty track normally used with proper gates;

(the other way up 😉 )

 

Ady

[Graeme]

Cheers Ady. 

Mine's in the post! The initial inertia to open my roof is a bit high due to the friction of the side timbers, so I hope the motor can cope. I might have to grease up my moving parts!

Graeme

 

[adyj1]

2 hours ago, Graeme said:

Cheers Ady. 

Mine's in the post! The initial inertia to open my roof is a bit high due to the friction of the side timbers, so I hope the motor can cope. I might have to grease up my moving parts!

Graeme

 

Well it certainly has plenty of grunt, although having friction doesn't sound ideal.

NB: When you open the box, the rack is right at the bottom - it looks like you've emptied everything out but there's another box... 

[Graeme]

So here's the inside. There's two runs of mini trunking. One for 230V and one for 12V and comms. The big white box is my cardboard and duct tape flat frame box. It's mounted on hinges to swing out to the telescope when in the parked position. It's 12V supply comes from variable output on the Pegasus PPB sitting on top of the pier, so that I can control it from within NINA. The small white box will house a DHT11 temperature and humidity sensor. I need to drill some holes in it! The medium box will house two Arduinos and two relays. The two conduits to the right are for the security camera and the supply to the roof motor. The low level shelf hides cables and provides somewhere for the 12V bench supply.  

Also comes in red!