Observatory on roof?

[garymck (Gary)]

Hi,

I may soon have the opportunity to house a telescope on the roof of a 3 story home in Northcote in Melbourne. The home has uninterrupted 360deg views of the sky that can never be built out. I'd love to house a scope there for imaging (light pollution notwithstanding). The problem is that there is no way to put a pillar in to the ground. The roof of the home is a tiled entertaining area, so I cant do much more than put the scope and a small roll off type cover. Vibration and movement from the house is the obvious problem. Does abyone have any suggestions for isolating/minimizing such movement? How to mount the pier? - I have a portable pier, and also an unused 10" diameter steel pier I could use - or perhaps a lightweight tripod on pads might be better? or do I need to start saving for some form of AO unit?

thanks for any suggestions,
cheers
Gary

[cristian abarca]

Hi Gary I looked into doing this when I did my renovations and I encountered too many problems. Apart from the vibrations ( the pier woold have to go all the way to the ground) ,there was the issue of the weight. I needed a whole new truss design to hold the weight. Secondly the water proofing was going to be difficult. The cover on the roof had to be of certain specification to be able to withstand strong winds as well as heavy rain this would make it heavy an a little impractical. The heat was also a factor. I'm summer you get the heat from thereof cavity and in winter from the heating. It can be done but for me it was am issue of money. I ended up building an observatory in the back yard for a fraction of the price.

Regards Cristian

[Murat (Mark)]

Hi Gary, I too had thoughts about a rooftop telescope.

Notwithstanding the opportunities for better 360 viewing, don't forget that less than 30degrees altitude is generally not ideal due to atmopheric interference with seeing conditions.

Rooftop introduces further light pollution and the need to create light shields. This is easy to do.

Another concern is atmospheric seeing interfered by air turbulence due to thermal effects of being on the roof of a house. This can affect the clarity of planets and nebulae for instance, and depending on what your goals are, you may choose a smaller area in the backyard with more limited viewing area. Please read the information in this link:

http://www.ayton.id.au/gary/Science/...Ast_seeing.htm and

http://www.telescope-optics.net/turbulence_error.htm (local air turbulence section)

There is of course the cost and inconvenience of rooftop setup/viewing consideration for most of us, but yours seems easier to set up.

Why don't you first try some viewing in the back yard (if this is an option for you), and contrast the seeing conditions with the rooftop first. Virbations will not be your only concern.

I must say I am out of my league a little here and you would be well advised to seek the response of more seasoned forum contributors/astronomers in this forum. Check also cloudy nights forum for ideas about rooftop observatories.

I suspect from the tone of your query that you are simply asking contributors for advice about how to make it work on the rooftop, rather than asking should you do it on the rooftop. Please clarify your question in this regard for us also.

Regards and good luck,
Murat

[garymck (Gary)]

Hi Murat,

your'e right, I need to make it work as well as possible on the rooftop, here is no other option for me. I can think of a large number of possible problems, but since it's the only option I have for a permanent setup, I'll just have to make do.

It may be that the limitations mean I can't do it, or that I need to use an AO system to help with the Vibes, but I'm sure I'm not the only person who has attempted this!
cheers
Gary

[steve000 (Steve)]

Sounds like a good idea however vibration will be an issue.. take a look at this link. its a video of the moon taken from an observatory on top of a 12 story building at QUT in qld. http://nerdipedia.com/tiki-index.php?page=observatory

12 storys and 1000's of tonnes of concrete.. take a look