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View Full Version here: : How high are your walls?


pmrid
08-08-2011, 07:50 PM
I'm re-inventing my obs by adding a warm room and raising the walls. It's a roll-off design with 2 piers. The original walls were only 1200 high and I had to devise some quick-and-dirty panels to block the wind. But there remained a real weakness in that when the roof was rolled back, the roof tended to act as a funnel and air often rshed through the obs despite the panels.
So I've decided to make the wall panels permanent on all 4 sides and they are now at 2100. Also, I have cut my piers down so they are at most 700mm abouve the floor level. But I'm using big mounts and big scopes so that's quite a good height for me. But the high walls have put some new limitations on the sky I have to work with and the time also. I was wondering what others have done in relation to walls. I recognise of course that most domes behin with high walls and a good deal less visible sky. I was really thinking about people with roll-off systems.

Peter.

[1ponders]
08-08-2011, 09:06 PM
Mine are 2000 Pete with the roll off roof. I don't find them any limitation.

ZeroID
09-08-2011, 09:53 AM
Depends a wee bit on the distance between walls. Mine will be 1950 south wall, 1850 north wall and 1800 apart but the pier will push the mount up so I get to about 25 degree sth limit. It's all soup below that anyway.

ballaratdragons
09-08-2011, 08:49 PM
A good way to work out how high to have your walls is to place your scope pointing at 30 degrees altitude.
Make your wall height to match that angle. Anything below 30 degrees in the sky is rubbish.

Obviously the height will depend on the distance from scope to wall.
A large obs will end up with a slightly higher wall.

pmrid
10-08-2011, 03:09 PM
Loved the illustration Ken. Thanks.

Since I'm at -27South, I am using the scope in the CWD position as the guideline. That seems to be pretty right. I plan on keeping my north wall partly fodling so I can catch some of those elusive northern delights occasionally. The others are now fixed at 2100 high. All I have to do now is paint them - and that is one of my least faourite jobs.

Peter

GrampianStars
13-08-2011, 06:54 PM
My Obs walls are 2.00 mt. heigh and fold down to 1.50 mt. if required
Keeps the wind out when up. :thumbsup:

asimov
13-08-2011, 08:08 PM
Mine are 1.8M high, With the scope slightly offset to the SW & the obs is 3M sq. I can get to everything that I'd like to see or image.

Alchemy
13-08-2011, 09:25 PM
I had my previous observatory, around 1.85 m the height was determined by allowing the pole finder to work, so it needed to get a fix.

The positives of high walls are, protection from wind, security,
The downsides are obviously no access to lower egions of the sky.... For long focal length work this is not such a problem, but for comets which can be quite low this can be disappointing

My last observatory allows the whole building to roll away, given I went to a refractor, the wind is less of an issue than a large newt.

Paul Haese
14-08-2011, 07:11 PM
1.8m for mine. That works well.