Quick n Dirty Mini Observatory

[Ramius (Bill)]

Hi
Thought I would post a quick summary of my version of the “mini” remote observatory. Not 100% finished but close – just need to complete insulation and tidy up cabling. My objective was quick, simple and cheap. I do have a reasonable workshop which streamlines some things but nothing here is complicated. Hopefully this adds to the library of ideas for budget observatories.
The closed size is approx 1200mm x 1200mm x 1500mm tall. It could have been significantly lower if not for my need to maximise viewing angles. Sadly it most resembles a blend of doghouse and outdoor dunny but is also neat and simple.
Hard to say how this will hold up in the weather but I think it should be ok if paint is kept fresh. Light rain has been no problem but remains to be seen how watertight it is in a real storm.


Pier
140mm x 6mm steel pipe welded to 10mm plate plus very short rat cage for minimal flex topped by brake disk mounting plate. The short cage means access to the bolt for Skywatcher mount requires a spanner but is simple enough.


Enclosure
The observatory currently houses an AZ-EQ5 and small refractor or C8 SCT but was designed to (hopefully) accomodate an EQ6R-Pro swinging a 5 inch refractor or 200mm newtonian. Upgrading to an EQ6 would simply required the brake disk be replaced ($20-30).
The low height of the base enclosure relative to the installed mount is critical to maximise the telescope swing radius relative to enclosure footprint. This enabled the enclosure to accommodate a decent size scope while limiting footprint dimensions to 1200mm minimising the number of sheets of ply required. The low base enclosure sides also allows access by simply stepping over the wall eliminating the need for a door.


Enclosure is framed with cut down framing timber (H3 for base) held together with 65-75mm screws. Cladding is Bunnings 6mm structural ECO-Ply simply nailed to frame. Much cheaper than marine ply but still uses waterproof glue unlike interior ply. In the interest of re-use and cost saving I am using reclaimed polystyrene for insulation.
The slide off roof utilises heavy 1200mm drawer runners. These are rated for 125kg. Not sure I would load them to that but they are plenty for this application and do not require additional support.
Waterproofing was a major concern. The top overlaps the lower section on all sides to facilitate this. The removable “door” is framed with aluminium strips for waterproofing and faces south which will seldom receive direct rain at my location.

Cost
Manufactured goods are cheap but basic materials are just ridiculously expensive and screws, paint and bits n pieces would be another $100 if you don’t have them already lying about. Adds up fast even for small jobs but still small beer compared to everything else in this hobby:
Pier - $110
Concrete - $100
Framing Timber - $130
Ply - $160
Runners - $100
Approx Total - $600
Build Time
After several days googling ideas and roughing out the design the build took about a week:
Fabricate pier - 1 day
Excavate and concrete pier - 1 day
Build box - 2 days
Paint - 2 days
Assemble - 1 day

[wasyoungonce (Brendan)]

I love it Bill Built to suit...well done.

[AlexN]

Thats awesome, and about perfect for what I can have in my yard... I've got his bookmarked for winter... Summer in Brisbane, it rains too much to get a half reasonable footing in the ground for a pier, so I'll wait until winter, then try to replicate this reasonably well.. For me, even if the scope comes inside at the end of the night, but the mount stays polar aligned outside, its a win! With my scope being a 1.15m long APO refractor, I think I'll have to settle for that, or expand the dimensions of your mini-observatory a little bit...

[Leo.G (Leo)]

The sliding top won't tip if hit by a breeze or anything?
It looks precariously balanced.
Still, it looks like the perfect set up without the expense and landscaping required for a dome.


I had a similar design somewhere on scrap paper I drew for a large box I'm making (half made, combination health and laziness) for my RC8 and mount to make it somewhat portable if it fits in the back seat of my old Falcon (barely I believe) where the lid would double as a platform for computer, eyepieces and other items. In my design I incorporated some old aluminium adjustable crutches cut down and on saddles to swing down when the lid was open (slide or sliding rail which lifts the lid slightly higher) to give the pivot and slide lid some strength (support leg/legs) when open without any additional weight (minimal) or bulk and they are already made.

[Crater101 (Warren)]

That's very nicely done! I have to admit a touch of envy as to what you've done there, great work. I really hope the rain / weatherproofing holds up for you, and do keep us in the loop on how it all performs.


(As I wonder how I can convince the wife to let me try this idea...)

[AG Hybrid (Adrian)]

oh that is pretty cool!

[Ramius (Bill)]

Originally Posted by AlexN

Thats awesome, and about perfect for what I can have in my yard... I've got his bookmarked for winter... Summer in Brisbane, it rains too much to get a half reasonable footing in the ground for a pier, so I'll wait until winter, then try to replicate this reasonably well.. For me, even if the scope comes inside at the end of the night, but the mount stays polar aligned outside, its a win! With my scope being a 1.15m long APO refractor, I think I'll have to settle for that, or expand the dimensions of your mini-observatory a little bit...

Alex
Thanks - pretty happy with it. I currently have a 8" Skywatcher Newtonian operating in there (just shy of 800mm long) but a 1.15m refector with image train on the end as opposed to offset would be significantly different. I agree you would probably need to demount scope at night but even then you would need to carefully consider the clearance to the roof section in its retracted position.

[Ramius (Bill)]

Originally Posted by Leo.G

The sliding top won't tip if hit by a breeze or anything?
It looks precariously balanced.
Still, it looks like the perfect set up without the expense and landscaping required for a dome.

Hi Leo
I agree it looks it but not really precarious at all. The runners are rated for 125kg so reasonably sturdy. Iwouldnt want to leave it open like that in a gale but short of that its fine.

[Ramius (Bill)]

Originally Posted by Crater101

That's very nicely done! I have to admit a touch of envy as to what you've done there, great work. I really hope the rain / weatherproofing holds up for you, and do keep us in the loop on how it all performs.

(As I wonder how I can convince the wife to let me try this idea...)

Hi Warren
Thanks. No issues so far. We have had a couple of decent storms and bone dry. Also stays at a reasonable temperature in high 30's but i might consider a small exhaust fan and thermostat.

[toppy (Pete)]

Hi Bill,

Very nice build. Not questioning your pier costing but just wondering how you achieved the excellent quality for $110. Could you provide some information about the pier such as diameter and gauge please as I would like to replicate x 4? Also, is that mount base a disc brake rotor, if so, can you advise part number or specs?

Thanks
Pete

[TrevorW]

Just a thought is there space for air to circulate through the box as it can get very hot in there, I know my ob even though insulated will be withing ambient on a 40 degree day

[alan meehan (Alan)]

Love your build BILL well done, I have a roll of roof observatory, but now my neighbor's palm trees are in the field of view, I need to step back further in my yard and since I am doing wide field small mount this would be perfect thank-you for showing this, great

[Ramius (Bill)]

Originally Posted by toppy

Hi Bill,

Very nice build. Not questioning your pier costing but just wondering how you achieved the excellent quality for $110. Could you provide some information about the pier such as diameter and gauge please as I would like to replicate x 4? Also, is that mount base a disc brake rotor, if so, can you advise part number or specs?

Thanks
Pete

Just dropped past this old thread. The 140mm x 6mm pipe for the pier was obtained used from a local metal shop.
The mounting plate is a disk rotor. I don't recall the exact spec (I think the centre hole was 60mm or 61mm diameter) but Repco has a useful search for rotors that includes the centre hole diameter with generally several available under $20. Drilling really requires a drill press.

[Ramius (Bill)]

Originally Posted by TrevorW

Just a thought is there space for air to circulate through the box as it can get very hot in there, I know my ob even though insulated will be withing ambient on a 40 degree day

For the record: The 'box' is fully insulated and has a thermostaically controlled exhaust fan. Still gets pretty warm in summer but not excessively so.

[astronobob (Bob)]

Quick & Dirty, nah, looking Clean, Sharp and On-Point to me.
great way to make Astro Life much simplified and maximise Sky-Time

[Ramius (Bill)]

Thanks Bob
It has absolutely revolutionised the whole process - almost certainly the best investment i have made in this hobby.

[strongmanmike (Michael)]

Originally Posted by astronobob

Quick & Dirty, nah, looking Clean, Sharp and On-Point to me.
great way to make Astro Life much simplified and maximise Sky-Time

Couldn't agree more Bob, great job Bill

Some cool solutions to be had out there, to cater for all

Mike

[toppy (Pete)]

Thanks Bill, much appreciated. The Repco filter works a treat when searching for the correct rotor to match a mount.

Originally Posted by Ramius

Just dropped past this old thread. The 140mm x 6mm pipe for the pier was obtained used from a local metal shop.
The mounting plate is a disk rotor. I don't recall the exact spec (I think the centre hole was 60mm or 61mm diameter) but Repco has a useful search for rotors that includes the centre hole diameter with generally several available under $20. Drilling really requires a drill press.

[Leo.G (Leo)]

Brake rotors can be had for next to nothing if you go into a brake workshop, they pull them off and throw them out. I do a lot of brakes for friends and have several old rotors here (I rarely throw any steel items out) because I use them for varying projects involving presses and rolling steel, they bolt together back to back and work a charm. I'm not sure on welding them I haven't tried that, they used to be cast iron and I hated welding cast even though I was the only one in my fabrication engineering class to pass the unit first go (it's all about pre-heating and post-heating, including heating the welding rods).
It would be no good me checking if I have any suitable for you because postage to melbourne is worth more than the rotor but local wreckers if you know what car they fit, you can't go wrong.
I should check if they suit my purpose for my piers top plate, I was going to plasma cut a 10mm top plate and weld a centre I machine up on the lathe, a disc rotor is sounding so easy and I've seen plenty of members on here using them.