Warm climates and Backyard Observatories

[lazjen]

I'm in the process of working out what backyard observatory I'd like to set up as I've reached the stage that I'm like something more permanent that I can use more quickly during fickle weather conditions like we've got now.

I'm currently thinking of a roll off shed design, mostly because it's likely to be significantly cheaper than a dome.

I am concerned though about what I need to consider for this given Brisbane conditions - hot and very humid - plus (the possibility of) tropical storms/winds.

Will I need to insulate the walls/roof to reduce internal heat during the day? If I do that, am I likely to be affected by the insulation at night?

What's the best way to handle the humidity?

Any tips or thoughts appreciated. I'd especially like to hear from people in a similar environment to myself what challenges they've encountered / overcome. Thanks.

[ZeroID]

I'm in Auckland, NZ. It gets pretty muggy here although not as hot over your way of course.
My roof is insulated to reflect heat away, my walls are not insulated, you want the Ob to cool down to local ambient. My floor is raised which encourages breezes and draughts to move the air. If you can encourage natural ventilation, low air inlets, higher outlets and still keep the bugs and creepies out it's the best answer.
Cool off for me is to open the roof as soon as the sun gets down to the horizon. Muggy is what you live with, aircon seems not to work too well with the roof open :question: :lol:

[lazjen]

Ok, that makes sense. Encourage a natural flow of air. Maybe put one of those whirly-vents on the roof.

I did actually consider a/c for when it was closed to dehumidify, but I'd prefer a more passive solution.

Do you have any pics of your setup?

[AstroJunk]

A free standing air-conditioner (3-400 bucks) is the only way I could properly protect my gear during the wet season. Just put it on timer for a couple of hours a day when the humidity is monstrous for prolonged periods and the observatory is not in use courtesy of the clouds.

Can come in handy too on hot dry days to bring the observatory down to the expected ambient a few hours in advance...

[lazjen]

I had a look an your website - your observatory is a dome, right? Does it have any ventilation (when closed :) )? If not, I can well understand the need to the air-conditioner.

I guess I can construct using a passive ventilation system and add the a/c later if it's not enough. If I add a/c I think I'd like to add solar panels to offset the power cost, but that would be another challenge too (connecting to a move-able roof).

[ZeroID]

Nothing clever to see on my setup, it's just a cheap tin shed that 'leaks' air a lot. The roof used to leak water but I fixed that and gave it an double skin insulating effect with a silverised car Tarpaulin which puts an airgap between the roof and the tarp. I may add some foam insulation next time, the tarp should last about 3-4 years and it is cheap and easy to replace.

I'm lucky in that the Ob sits inside it's own small fenced off area which provides a big degree of side shading and the aspect is southerly which is where all the cool clear breezes come from. The only wall that gets much sun is top half of the north wall and the roof. East, West and South get almost none.

I've heard it suggested that planting bushes on the sunny sides to shade the uninsulated walls will help as well. As you say if you can do it for free all to the good.
Airvents in lower sth walls with gauze filters to keep crawlies out might be a good start.

[AstroJunk]

Yes, it's pretty weather tight. I know of one dome with a metal lattice floor which is great for airflow, but lets the critters in - and snakes love cosy observatories!

I had considered putting in some vents, but I had the aircon sitting around and it just works so well (even the smallest unit is designed for a room much bigger than an observatory, so it doesn't take long to rip the humidity out of the place :thumbsup:

[lazjen]

I'm surrounded by buildings on most sides, except the east (it's got the streetlight :rolleyes: ). So while the site gets a good dose of sun during the day, by late afternoon it's in the shade, so that will be helpful.

The afternoon winds tend to come from the east as well, so that will be useful for mid to late afternoon cooling/ventilation purposes.

Given the torrential downpours we can get here, I'm going to have to make it as weatherproof as a house.

And because I don't have the tools, the skills and barely the time, I'll have to hire people to get it done. Fun times ahead. :p

[AstroJunk]

it ***Might*** be worth considering a Sirius dome then. They aren't cheap, but neither is a custom shed, and they are as easy as anything to put together, last a lifetime and can be easily moved ...

My primary reason for the dome was that I could control it remotely, but that's another story...

[lazjen]

I did get prices for a Sirius dome, but I suffered some sticker shock when I saw how much it would cost (I'd like to go automated as well).

No matter what I do, I need to get some base down (concrete slab), a pier on it and power to it. So they're basically fixed costs.

I just have to work out what's cheaper: the dome + its automation gear versus the roll off shed and it's automation gear (seems simpler and cheaper - open/close roof only, no aligning with the scope). Weather detection system would be the same either way, so I don't have to factor that into the decision.

I also have some delusions of getting another scope at some point and setting it up at the same time and thought a roll off would be easier for that.

[AstroJunk]

I had a sticker coronary...

There are plenty of permanent observatories in the area - you should book yourself a tour of a few to get ideas.

[lazjen]

There are? A tour - who, what, where, how? :)

[AstroJunk]

Start with me as a dome archetype, and I'll put you in contact with appropriate others with various sized roll-offs. I don't know of any automated roll-offs in SEQ though, you are going to have to go and see Paul Haese in SA for that!

[lazjen]

Ok, that sounds like a plan. I'll PM you.

[moont]

I put up a roll-off roof observatory in March 2003 in Blakeview, a suburb of Adelaide. It was used up to 100 nights a year until we moved in 2012. No problems with mechanism sticking or jamming. The rails were standard shed door rails and rollers turned upside down. Paid $1400 in 2003. Had another manufactured in about 2009 for place up in country SA and paid $2175 but that's inflation for you! As I do photoelectric photometry, tripod on concrete in backyard is not steady enough. Surprising how walking around on even a thick concrete slab causes noticeable vibrations and a breeze plays havoc with a telescope in the open. Chose roll-off roof observatory mainly due to price. It is a very good solution for a warm climate like Adelaide as you quickly reach ambient with roof rolled off. Also, can slew around quickly without having to move a dome. Walls are sufficient to dramatically attenuate effects of wind and block out most stray light. I was able to do photometry on even quite windy nights and with neighbours backyard lights on. Trick for good sliding roof is to assemble frame first and get the roof rolling before concreting posts in. The colorbond sheets should be put on last. As I don't have a website happy to answer questions and send photos via email. Example of published work from Blakeview observatory at: http://www.aavso.org/sites/default/files/webpublications/ejaavso/v34n2/156.pdf

[lazjen]

That sounds pretty good. I'll PM you my email details. I'd be interested in how you did dealt with the concrete slab vibrations too.