Quote:
Originally Posted by Joshua Bunn
So a question, I'd be interested to hear the opinions of you ladies and gents on whether or not you think putting the scope at 8-9m above ground is a waste of effort in terms of getting better resolution images. I've read and heard that getting above the ground based level seeing conditions has a positive effect on the FWHM of your images.
Who thinks it's possible compared to having the scope at ground level?
Josh
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Quote:
Originally Posted by Paul Haese
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As to the seeing effects at ground as opposed to 8 meters up; whilst I have read there can be significant gains made it would depend on the size of the scope installed, what the focal length/image scale will be and the local seeing conditions. I suppose it also really depends on what you intend to do with the system in the long run. Is this going to be a research grade system, will you be trying to attract scientists to use the equipment at hire? If not I guess you have to ask yourself if it is worth the effort to elevate the rig. Can't answer that for you.
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What Paul said!
My approach to building an obs has always been entirely empirical and based on half a dozen or so basic dos and don'ts and the number of dollars I have AND the fact that I'm an engineering ignoramus.
Dos & don'ts:
- thermal mass is bad, mmm-kay! So no concrete pad for me .... and don't put your obs next to a house (ooops! ... but my excuse #4 below))
- a pier footing should be substantial and isolated from the observatory structure
- the telescope pier should be >=5mm thick buttressed aluminium or steel tubing anchored to the footing and be about 250mm in diam to minimise deflection and resonance .... and it should NOT have a bird cage on top!!!
- should have convenient access (the older you are the more important this becomes!)
- should allow adequate ventilation
If I was an engineering genius, like you
, would I build a tower obs? Probably not, because I've never seen anything
definitive to say that seeing is
noticably better at greater than 3m above ground level (the aperture of my scope is about that). I can imagine it
may be better, but I'd be guessing that it would be marginal at best compared to normal seeing conditions.
Having said that, unless No. 4 in my list above rings true for you, I'd press on.