Observation

[Visionary]

Via a complex set of circumstances I have the opportunity to build an observatory. Due to some unique topography the possible sites for the observatory are limited.Understanding that insulation of oscillating vibration and movement generally requires a pillar mount. How realistic is it to consider building an observatory utop my house, a third story? I understand that it wouldn't fit the establish and tested observatory construction norms. If I was to place the scope on a Giant Tripod rather than a pylon would the mount be sufficiently stable for "general astronomy"? I am not trying to set records with the observatory I simply an easier way to enjoy Astronomy.
I have a Civil Engineer coming by home next week for a sketch and brief. I am not looking for world beating Astrophotography just simple planetary imaging and one of the larger nebula etc:
Even before the meeting next week I am making an allowance of some 50k for the project, the price of a pool. In considering this it will be impractical to include a pylon in the build. Having previously worked on a number of projects were the abolition of oscillatory vibration was necessary I am confident that I can effectively mitigate the worst if vibration through the structure.
Living on the out rim of the Sydney basin, I have surprisingly dark skies. So.... What are your thoughts, proceed or save my money?

[xelasnave]

I don't think you will be able to do any photography and suspect you will be limited to visual observing.
Apart from the possible flexing of the house heat from your home may also cause problems.
I don't know anyone who has done similar.
I will be interested in what others think but personally I like my pier sitting in bedrock away from the heat sink I call my house.

[Visionary]

Your points are well make and each point is perfectly valid. Hopefully I will get a few responses so that when the Engineer comes by I can list all the issues prior to moving beyond the White Paper phase.
Again many thanks Aleaxander. If there is anything else you can think of that would impede the function of a "roof top observatory" please let me know. I think the appointment is towards the end of next week.
Cheers

[doppler]

Check out some of cometcatcher's atrophotography. He has taken some amazing pic's through a kitchen window....on a stadard heq5 tripod in a highset queenslander(timber floors).

[ZeroID]

Hi David,
It's been done before, Cloudy Nights, the US Astro Forum has several members who have done it with reasonable success. The two main probem areas are vibration and thermal distoortion off nearby hot roof surfaces that are cooling.
Depending on circumstances piers have been built through two stories and been adequate for imaging with care. House construction is important obviously, a concrete block construction being obviously more solid that a wooden structure for example.
For visual purpose it certainly can be done, for planetary imaging using video stacking it is still workable. For DSO longer exposure imaging it would need to be pretty solid and isolated from house activities but at high ISO with a DSLR and 30 -60 second exposures, why not. Might pay to send the rest of the family to the movies maybe but it is workable. Your budget ( wish it was mine !! ) gives you some options.

I would suggest that if you cannot get a pier down through the house\garage then I would look to put very solid beams or steel across two lower floor walls that were directly above foundations. That would be the best option of isolating any floor vibrations. And image after evryone has gone to sleep.

Good luck with your idea, keep us posted if you go ahead. In these crowded living days you have to look at every option to follow your passion.

[Kunama]

David,
My brother and I built such an observatory for an elderly fellow in South Australia many years ago. His house had been extended with a 'parent's retreat' added as the second floor. The second floor room was about 4 metres across the short aspect and 8m long.
We ran two 12" steel I-Beams across the floor at one end of the large room.
These beams sat atop steel posts that went through the floor onto the ground floor slab. Six posts in all, 4 of which were located in wardrobes on the ground floor, two became 'Feature Columns' and were clad in gyprock.

We then installed a 2.7m x 4m false floor 300mm above the actual floor with 10mm isolation gap to the beams. The false was floor was carpeted as were the tops of the steel beams. Two smaller beams connected the larger ones and carried the pier. A polished redgum step ran the full width of the 4m room.

Someone else was going to be building a dome. I never went back to see if it was completed.

[speach]

Yes without any question at all. Here is a pic of my 'observatory' as you see it's around 3m up , and I take photos through a 1500mm focal length and 800mm f/l scopes. the only limitation is that while the photo sequence is going I'm not able to move around, moving causes vibration.
I first tried a central pier but that wasn't stable enough, so I'm now using a tripod with a strop that's tensioned so it pulls down from the centre of the mount.

[iborg]

Hi

Your engineer will almost certainly think of this, but, placing the observatory above the bathroom / toilet area would probably give an advantage of extra walls, close together, and improve stability.

Better, as suggested above, piers down to the ground or concrete slab.

Enjoy spending the money!

Philip

[AussieTrooper]

I looked at doing it this year whilst my house is undergoing renovations. The cost would have hit $150K, due to the requirement for independent piers that had to go through established walls in the house.
I pulled the pin on it.
Hope you have better luck than I did!