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Adam J

Adam J's Mini Roll Off Roof Imaging Observatory

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Hi all,

I am sorry to say that this is not going to be a greatly detailed build thread as the Obsy is already complete, so just a few posts to show you all what I have been up to.

I started a long time back in about mid May working one day per weekend only. I decided to build my observatory as I was having less and less time to image on an evening what with having a 6 month old baby at the time 10 months old now. Essentially I did not have the energy late on an evening to drag lots of heavy equipment outside spend and hour and a half setting up and then find that the weather had turned on me.

So I decided to eliminate setup time and hopefully take better images by building a small observatory to allow me to image on short notice as and when I wanted.

I have a short south facing garden with some short ish trees at the end and so I knew that I would need to build my observatory close to the house to get the views I wanted and by placing the obsy to the east side of the garden I would also be able to eliminate any direct light from the local street lighting (which thankfully is turned of at 11pm anyhow) and next doors bathroom window.

Due to the obsy being so close to the house I wanted to block as little view to the garden and light into the house as possible and so I knew this was going to have to be a compact build. I also decided that the proximity of the kitchen table would allow me to setup my laptop in the house and eliminate the need for a warm room next to the scope.

As a first step i set about working out the minimum sized obsy that could fit a 8 inch F5 Newtonian (as I am unlikely to afford a mount that can handle any more than that for imaging any time in the near future) with my current imaging scope being a SW130PDS mounted on a HEQ5 Pro. This all resulted in a 1.7m x 1.7m x 1.5m (W x D x H) obsy.

I decided that I would keep the scope quite low within the obsy and not attempt to look directly at the horizon as I am surrounded by houses and there is no point in being able to see lower than the roof line, this also gives me better protection from wind. I also decided to raise the obsy floor about a foot off the ground to improve the available viewing angles to the south and allow me to make my roof rails high enough for me to be able to walk under without banging my head, quite important as they are running across the patio.

I am on a budget so the small size also helped with the cost of material and I was able to work it so that the off cuts from the timber cladding and frame were of the correct length to be useful in other areas, hence very little waist wood. This also meant that I went for a concrete pier 25cm x25cm x 110cm made by creating a form using ply wood with internal steal reinforcement rods. The pier base was dug into the ground 70cm x 70cm x 60cm having reached a gravel layer and the water table 60cm below the surface. I poured the base and pillar on two separate weekends as I was mixing by hand and I could not get it all done in one day. I used PVA and the reinforcement bars to tie the two pours together and its has resulted in a very sturdy pier. The top was finished with a adapter plate and a ply wood top with 3 x M14 threaded rods sunk into the top of the pier while still wet.

59a0ae2a1f70c_2017-06-3019_13_38.thumb.jpg.eb8976abc860e11623e29698b3af6c9d.jpg

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I get quite a lot of pleasure from making things myself in this hobby as it gives me a sense achievement when I look at the end result (my images), sometimes it sames me money and other times it means I get exactly what I want how I want it. In this case it means that I decided that I would build the obsy 'enclosure' from scratch. I decided that I wanted to isolate the pier from the observatory itself so as to keep down vibrations (there is a chance that I may decide to observe at some point but only in a minor capacity given my light pollution). The size of the obsy was sufficiently small so as to enable me to use only four supports at each of the corners just so long as I used some nice thick wood beams to support the perimeter of the floor / base in this case 2 x 6 inches. The remaining structure being made from 3 x 1.75 inch beams.

As quite some pressure would be exerted onto the four corner foundations I decided to dig down about a foot and fill with hardcore then concrete and cap with a pair or bricks. I later decided to raise the floor further using concrete blocks when I realized I would not be able to walk under the roll off roof beams without banging my head on them (this change had some consequence later in the build).  Surprisingly with the permission of the wife I was allowed to attach the far side of the roll off roof rails to the side of our extension. The rails themselves are made of 4 x 2 inch beams. I should note that all the wood used in my build has been pressure treated.

59a0b32db9c08_2017-07-0117_19_21.thumb.jpg.8c97c55307a85e9c53a7b276c0d2e0be.jpg

 

Edited by Adam J
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Great work... I can relate, I just finished my obsy yesterday and started polar aligning. I also wanted to keep the cost and size down not too take too much yard space. 

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Nice work, congrats ! Wish you to finish your obsy the soonest and of course... clear skies. :smile:

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Cheers, Guys.

I decided to go with sliding gate v-track rails and v-grove wheels for the rolling gear primarily to reduce rolling resistance as the roof did end up heavy as I build things to last. 4 x wheels one at each corner works well for the size of building.

I decided to roll the roof off to the north as the house is exactly north south orientated and this would allow me to partially roll the roof off and get a good view to the south while providing additional shelter.

To allow extra clearance for the scope I build the roof up about 45cm at the back and 20cm at the front, this also allows sufficient clearance for me to be able to walk inside the obsy without banging my head although I am only 5'6'' so that is not a huge clearance required. I actually started out with a much larger height to the south (as seen in the picture) but then measured the total height which was over 2.5 meters and so I reduced it so that I was not above the legal maximum for a garden building.

You can also see the cladding starting to go on. I used seasoned dry untreated 18mm ship lap as I have had problems with shrinkage in treated cladding before causing gaps to emerge as they often take dry wood and treat it causing it to swell and then place it straight onto the shelf. The ideal is to leave it to dry for a while before applying it but I dont have time for that. The off cuts from the 2.4m lengths of cladding on the sides are exactly the correct length to clad either side of the door.

59a15e4d4cedd_2017-07-1714_56_21.thumb.jpg.9334aa2c102c679d423728e4b7d48d27.jpg

Edited by Adam J
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This is looking splendid – I like a pent roof: it looks good on a small shed, is strong, and doesn't need much of a pitch to be effective.   I also chose a north-south alignment with a roll-off towards the north, but not having the skills you do, I had to get someone else to build it.  Good luck with the completion (and subsequent use!)

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5 hours ago, AKB said:

This is looking splendid – I like a pent roof: it looks good on a small shed, is strong, and doesn't need much of a pitch to be effective.   I also chose a north-south alignment with a roll-off towards the north, but not having the skills you do, I had to get someone else to build it.  Good luck with the completion (and subsequent use!)

Thanks, but its already finished :) I was just poor at updating progress along the way so am doing a little write up post completion.

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Excellent job, well done. Looks really sturdy.

The pier is similar in width to my obsy build (I'm just building the pier at the moment). I've been wondering for some time whether this would be too thick, but your build has re-assured me! Please take a look at my thread.

I appreciate you've already finished your build, but would be good to see lots more pictures. Thanks

Kev

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Ok....I just remembered that I left this thread hanging several months back, so this is going to be kind of skip to the end....

Essentially it was lots of hard work but a complete success in the end. I have been using this for a few months now and its vastly improved my imaging. Seems to have held up really well in all the winter storms so far. Could not be more happy with my tiny little obsy. You can see the warm room in the background of the third picture ;)

Long story short its a 6ft x 6 ft rolling roof with a flap at the south side.

I will take some internal images and post them soon.

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Thanks for looking!

Adam

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Looks great - congrats on finishing, getting up and running.

On 05/02/2018 at 00:04, Adam J said:

You can see the warm room in the background of the third picture ;)

Nice - and it has its own bathroom! :D

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Very nice what’s the flap for at the front for Neil 

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Very nice. Love the colour scheme too.

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1 hour ago, gtis said:

Very nice what’s the flap for at the front for Neil 

As the obsy is so small in order to allow the scope to see down to 20 degrees above the horizon (any lower is obscured by houses anyhow) without the walls further limiting the view it needs to be mounted high in the obsy.

That means that the top of the scope actually pokes above the obsy walls when in the home position. The flap foldes down to allow the roof to be rolled off while the scope is in the home position (pointing up) without it collecting the scope with it in the process.

Although the 130PDS scope in the earlier images sits quite low, I later extended the pier by 10 inches to account for the increased height of the obsy from adding the cement block supports late in the design process. 

Edited by Adam J

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I see it’s not part of the roof

i also like the colour scheme 

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I've been trawling around the net and SGL getting ideas for my own obsy when I stumbled across this!!. Your house and dobsy position is virtually indentical to my own so thanks for the pictures and build information, brilliant stuff, thank you.

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On 08/03/2018 at 22:32, ro88ieuk said:

I've been trawling around the net and SGL getting ideas for my own obsy when I stumbled across this!!. Your house and dobsy position is virtually indentical to my own so thanks for the pictures and build information, brilliant stuff, thank you.

No problem at all, if you have any questions please feel free to ask. 

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