22 replies to this topic

[DOBguyinGA]

Good evening to everyone,

 

I have been following this thread for some time, and I have not ever seen a reference to a pit-style observatory. I do not know if that is really a “thing”.

 

In the north some people have pit style greenhouses, and they seem to work quite well. They are easier to keep warm in the winter.

 

Here is the reason I am asking. I live in metro Atlanta, which is in the Deep South tornado belt. We have already had to spend the night in the basement twice already this year. At one point during the second event the winds approached 75 mph, which is the lower limit for a cat 1 tornado. It got pretty loud.

 

All of the usual styles of observatory would probably have suffered damage in those winds because they are above ground, and built just well enough to stand up. I am thinking of two metal rails on the ground to roll the roof out of the way, and a ramp, not stairs to access the observing area.

 

I would include a warm room for AP, cinder block walls, and a poured concrete floor. 
 

I would appreciate any/all comments on this idea.

 

Thanks in advance.

[PirateMike]

If it rains hard enough, how do you plan on keeping your observatory from becoming a swimming pool?

 

Pirate Mike

 

.

[VNA]

Hello, what about drainage?  Sump pumps? And then power during a storm?

Lots of considerations?

[Shubham]

If it rains hard enough, how do you plan on keeping your observatory from becoming a swimming pool?

 

Pirate Mike

 

.

[Victory Pete]

Cool, sounds like a good idea. I have a basement that doesn't leak. I think a sump pump and lots of crushed stone would take care of any water seepage.

Edited by Victory Pete, 20 June 2025 - 06:44 PM.

[kgb]

There is the Hartness Turret Telescope.

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[John Rose]

Seems to me I read of a major facility that built a reflector observatory similar to that. Not totally underground. But the rear end of the scope was below ground.   Apparently the idea was to help maintain the objective at an even temperature. The downfall was the scope was too close to the ground and it was not above "ground effects".  So the "seeing" was not as good as expected. 

[auroraTDunn]

Drainage??? Just build as a massive french well with french drainage. At least it would work in my side of the country where rain is not that big of an issue. Georgia, on the other hand gets alot more rain in shorter periods of time so yeah flodding 'could' be an major issue and needs heavy planning.

But I can think of many advantages, wind protection, more even heating cooling, ect. But another major issue to  deal with being that low is thermal, and in Georgia humid thermal lift which is more pronounced the closer to the ground you go so seeing through turbulent air is 'slightly' more of an issue - maybe. 

 

Not sure how much a wonderful idea in Georgia it would be. But out west? Hmmmmmm, interesting concept that could be worth exploring!!!

[kgb]

I seem to remember someone on Cloudynights having a below ground observatory. It was pretty cool too, if I remember correctly. Pretty certain it had a copper dome. I’ll see if I can locate it.

Also, it appears there is nothing new under the stars. This topic has been discussed before:

https://www.cloudyni...nd-observatory/

Edit: Found this while searching:
https://www.cloudyni...nd-observatory/

Edited by kgb, 20 June 2025 - 07:29 PM.

[TOMDEY]

Cool idea! --- Could also design it to function as a Fallout Shelter! The roll-off roof could be a slab of reinforced concrete a few feet thick. The skies would undoubtedly become Bortle one --- great for enjoying those ~little fuzzies~ Tom

[DOBguyinGA]

Good evening everyone,

 

It seems this site has been up long enough for ideas to recycle through newer members like me. This appears to be one of those cases.

 

My home has a basement, and no sump pump. The house is a bit over 20 years old, and there is zero evidence of a water problem. So proper sealing against ground water appears to be a viable alternative here. We rarely get snow, and if we do it will just be a dusting that burns off about 10 am the next morning. I doubt this is something that would work up north in locations that receive significant snowfall.

 

Anyway it was an idea for me to explore. Thanks to everyone for their comments.

[star acres]

Bare cinder blocks are very porous and alkaline. All concrete work is about subtleties. This is not an impossible idea at all but not cinder blocks.

[speedster]

The better question may be, "Has anyone built a pit observatory twice?"  Lessons learned from the first one would kill the thought of a second one.  It can certainly be done but everything about it is working against you.

[gordtulloch]

Good evening everyone,

 

It seems this site has been up long enough for ideas to recycle through newer members like me. This appears to be one of those cases.

 

My home has a basement, and no sump pump. The house is a bit over 20 years old, and there is zero evidence of a water problem. So proper sealing against ground water appears to be a viable alternative here. We rarely get snow, and if we do it will just be a dusting that burns off about 10 am the next morning. I doubt this is something that would work up north in locations that receive significant snowfall.

 

Anyway it was an idea for me to explore. Thanks to everyone for their comments.

Depends on your ground water situation. I live in a swamp (not literally but the groundwater here is abundant) and if my sump pump fails during a rain event I'm going to get water in the basement. Sealing is not the issue, there's no way you're going to seal a house against water incursion. You need to manage drainage and direct it away from the house, which is what weeping tiles and sump pumps do.

 

So building a pit observatory requires a very long term detailed understanding of the groundwater situation and active measures to manage it. 

[Shubham]

This is one of those things that are best described as “a disaster waiting to happen”.

[nof]

Ulugh Beg tried that some years ago in Samarkand. I visited there once and it is quite a construction. You stand underground in a channel and observe through the tunnel.
https://en.m.wikiped...Beg_Observatory

[archer1960]

Well-constructed poured concrete floor and walls, with the walls projecting a foot or so above the soil surface could probably be sealed well enough to keep liquid water out, but humidity and condensation is going to be a big problem in a Georgia summer. I don't see how you get past the seeing issue, though (pun intended).

[vsteblina]

Not technically a "pit obervatory", but I looked real hard at putting an observatory at deck level.  The flat roof of the observatory would be an extension of the deck.

 

Currently the current observatory is below the deck level, so it would not be much of a change in sky visibility.  The advantage is the spring winds are blocked in most cases.

 

I did not really investigate how waking on the roof of the observatory would work.  We live in a desert, so the rainfall issue was not a huge problem.  Snow melt, on the other hand might have been more of a problem.

[152ED]

Another idea to beat high winds would be a shallow geodesic dome with the top 1/3 removable.  You know it's an aerodynamic shape when all the flying saucers have that contour (only the ones that visit earth - the deep space ones are all orbs)

[DOBguyinGA]

Good evening everyone,

 

Actually, there is a high variability of reported sightings. Please see: https://unidentified...apes-and-sizes/

 

or 

 

https://newspaceecon...rted-phenomena/

[CharLakeAstro]

In the sticky thread "post a pic of your observatory",  there is one observatory which was built partially below grade. The owner had to comply with HOA height rules. 

[TxStars]

Would be better to build it at ground level then pile soil against it to keep it cool..

[900SL]

The only basement below the water table that didn't leak, in my 30 years of experience, was a caltite concrete basement we designed, forming part of Albert Bridge House in London. This was 10m from River Thames wall..

Edited by 900SL, 07 July 2025 - 05:59 AM.