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Old 05-05-2021, 11:13 AM
Startrek (Martin)
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Dehumidifiers in Observatories

The South Coast NSW is being hammered by heavy rain at the moment and will continue until the weekend.As my Nexdome Obs is water proof from the Dome down to the walls to the base , Iíve noticed a lot of moisture on the floor , the mount and tripod legs ( scope is dry )
Iím thinking a dehumidifier plugged in during inclement weather may reduce the amount of condensation ( rising damp ) in my Obs.
I welcome advice from folk who have had similar issues and how they minimised their moisture problems
Thanks
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Old 05-05-2021, 01:18 PM
glend (Glen)
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One thing I swear by is a heated insulated shroud, over my mount and pier. I Don't have to worry about a tripod, but I do get condensation on my pier. I made an insulated shroud that slides over my mount and about have way down the pier. Attached to my counter weight bar, low down, is a 25Watt decorative incandescent light bulb. This type of bulb produces a good heat for its size but little light ( they have that orange filament glow thing happening). The real purpose of the bulb is to create a chimney effect inside the shroud, the heated air rises creating air flow. I have a small opening at the top where I can feel the warm air exiting the shroud. This air flow keeps my mount dry, and above the condensation point. I have been doing This for years and there is no corrosion or rust on my mount.
As to the scope/s, I never leave a scope on the mount when rain is expected. Just bring it into house. The shroud system does not work with a scope on the mount anyway.
I did have a dehumidifier but all they seem to do is produce water without having much impact. I burnt two out before I gave up on them.
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Old 05-05-2021, 01:36 PM
Startrek (Martin)
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Quote:
Originally Posted by glend View Post
One thing I swear by is a heated insulated shroud, over my mount and pier. I Don't have to worry about a tripod, but I do get condensation on my pier. I made an insulated shroud that slides over my mount and about have way down the pier. Attached to my counter weight bar, low down, is a 25Watt decorative incandescent light bulb. This type of bulb produces a good heat for its size but little light ( they have that orange filament glow thing happening). The real purpose of the bulb is to create a chimney effect inside the shroud, the heated air rises creating air flow. I have a small opening at the top where I can feel the warm air exiting the shroud. This air flow keeps my mount dry, and above the condensation point. I have been doing This for years and there is no corrosion or rust on my mount.
As to the scope/s, I never leave a scope on the mount when rain is expected. Just bring it into house. The shroud system does not work with a scope on the mount anyway.
I did have a dehumidifier but all they seem to do is produce water without having much impact. I burnt two out before I gave up on them.
Glen
Thanks
Good idea
How about a single bed electric blanket ??
Variable heat control and timer , although they not waterproof they can handle a sweaty body lying on them with no electrical safety issues
I could wrap it around the mount and tripod with Velcro straps

Your thoughts ?
Martin
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Old 05-05-2021, 02:53 PM
Hemi
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Hi Martin,

Ive got a skyshed pod and the HTPE can mean they get very hot, and the joins are not water tight without sealant on the joins.
Darwin gets very hot, very humid and very wet. The Pod has performed outstandingly so far. I track the internal temp and humidity with an Arlec smart sensor from Bunnings. Its not the most accurate.

Ive installed a portable AC (12000BTU). Which can cool and dehumidify. Its reasonably effective, given the air gaps in the pod design. I suspect a bigger unit will help cool/dehumidify the pod (and neigbourhood) a bit better. I use foam filler for the gaps which does improve performance significantly.

In addition I use
DampRid buckets from Bunnings
Desiccant caps for the scopes
Telegizmo standard cover (foil, thin and light) for the pier and scope.

Cheers
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Old 05-05-2021, 04:41 PM
Startrek (Martin)
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Quote:
Originally Posted by Hemi View Post
Hi Martin,

Ive got a skyshed pod and the HTPE can mean they get very hot, and the joins are not water tight without sealant on the joins.
Darwin gets very hot, very humid and very wet. The Pod has performed outstandingly so far. I track the internal temp and humidity with an Arlec smart sensor from Bunnings. Its not the most accurate.

Ive installed a portable AC (12000BTU). Which can cool and dehumidify. Its reasonably effective, given the air gaps in the pod design. I suspect a bigger unit will help cool/dehumidify the pod (and neigbourhood) a bit better. I use foam filler for the gaps which does improve performance significantly.

In addition I use
DampRid buckets from Bunnings
Desiccant caps for the scopes
Telegizmo standard cover (foil, thin and light) for the pier and scope.

Cheers
Hemi,
Thanks
We donít have extreme humidity like the north , thankfully
My problem is not so much humidity, itís the amount of rain bucketing down all day and night
My NexDome is water tight but even though itís on a deck 400mm from ground level , thereís so much water hammering the Dome plus moisture in the air on the inside and around the dome edges on the deck , that somethingís gotta give
I used waterproof silicon around the base on the outside , looks like Iím going to have to seal the inside as well
The air is so wet and clammy at the moment , bad week
Itís going take a few days for the inside floor of the dome to dry out
Long term I may have to fit a 150mm angled flashing around the exterior base of the Dome for this type of bad weather
Thankfully the gear inside is ok but mount and tripod legs are damp ( scope is dry )
Cheers
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  #6  
Old 05-05-2021, 05:54 PM
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lazjen (Chris)
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For my dome setup, I've got it on a raised platform. The pier comes up through the floor as you would expect, and next to it I've got a hose that's the drain for the dehumidifier - so the water extracted exits the dome. I've got a timer to start it early in the morning and I run it for some period of time depending on how humid the conditions have been. This last few months it's been on a lot to deal with the high humidity.

I have not noticed any problems with mould, etc in the dome or with the equipment.
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Old 05-05-2021, 07:14 PM
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h0ughy (David)
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I have always had a dehumidifier. The original one had issues after 12 years continuous service. Just bought a new one with double the capacity and I run it at 50 percent.
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  #8  
Old 05-05-2021, 11:38 PM
Hemi
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Quote:
Originally Posted by Startrek View Post
Hemi,

I used waterproof silicon around the base on the outside , looks like Iím going to have to seal the inside as well

Cheers
My pod sits on a composite deck, the floor of the pod is a waterproof/ breathable membrane, beneath a waterproof laminate floor. all the wall joints are sealed with Sellys clear storm. I didnít seal the floor yet (inside or out) as despite two severe wet seasons ive not had any ingress. My plan was to seal at the floor inside as well after fitting the laminate tight to the side walls, but it hasnít been needed so far. The telegizmo cover protects from the heat, but also provides insurance should the roof leak in a tropical storm.

Last edited by Hemi; 05-05-2021 at 11:55 PM.
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  #9  
Old 09-05-2021, 07:44 PM
Startrek (Martin)
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The rain finally stopped after 4 days straight dumping 8 to 10 inches of rain on my NexDome
The rain was that heavy it was bouncing from the ground up into the air
My deck is 400mm from ground level
Carpet ties are soaked so pulled them all out to dry out the deck boards inside
All gear inside Dome including mount , scope and workstation are fairly dry
The carpet tiles have to go so need another waterproof solution
Re seal around exterior base of NexDome with waterproof silicon
Seal around inside base of NexDome with waterproof silicon
Apply 2 coats of Bond Crete on deck boards inside Dome
Fit 13mm or 20mm thick closed cell EVA foam floor mats or tiles with interlocking edges to floor of NexDome leaving a 20mm gap around the perimeter
Hopefully the above will keep the floor relatively dry after a 3 or 4 day deluge

Any comments or further suggestions ?
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  #10  
Old 09-05-2021, 08:24 PM
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Hi Martin...this wont sound crazy if you think about it for longer than the time it takes to dismiss it out of hand....get a tarp that covers the lot to ground level...you need not have it on most of the time but when it is clear you are in for a week of rain cover the lot...the dome and deck...I say this because I bet it is the only way to stop all water in those really wet periods...do all your water proofing for sure..and this approach will allow you to keep your carpet tiles...think about it..piece of mind for under $100...
Alex
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Old 09-05-2021, 08:36 PM
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peter_4059 (Peter)
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I've got a solar powered fan that sucks the hot humid air from the high point in the obs to the outside. At the low point (floor level on the opposite side) I've got a vent. This doesn't deal with bulk water ingress due to poor design however so far there has been no issue with moisture issues despite our humid and wet Brisbane conditions.
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Old 09-05-2021, 09:16 PM
Startrek (Martin)
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Quote:
Originally Posted by peter_4059 View Post
I've got a solar powered fan that sucks the hot humid air from the high point in the obs to the outside. At the low point (floor level on the opposite side) I've got a vent. This doesn't deal with bulk water ingress due to poor design however so far there has been no issue with moisture issues despite our humid and wet Brisbane conditions.
The NexDome is an excellent design , all my gear is dry after the deluge but when rain is hitting hard surfaces like pavers surrounding my dome and bouncing back up to the underside of the deck boards then you have to seal the deck boards from any ingress
An alternative was to to pour a 100mm slab on the ground which I didnít want to do due to being a permanent slab ( my deck and Dome can easily be dismantled and relocated if needed in the future ) and Iím a long way from the road for a cement mixer to pull up and pour into wheelbarrows which would have to pushed up a steep driveway or concrete pump etc..$$$ it would have been a hand mix and pour job ( pain in the butt )
A 100mm slab would have flooded as well due to the deluge
The deck was the best solution and still is , just have to seal and waterproof the deck
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Old 09-05-2021, 09:20 PM
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peter_4059 (Peter)
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Quote:
Originally Posted by Startrek View Post
The NexDome is an excellent design , all my gear is dry after the deluge but when rain is hitting hard surfaces like pavers surrounding my dome and bouncing back up to the underside of the deck boards then you have to seal the deck boards from any ingress
An alternative was to to pour a 100mm slab on the ground which I didnít want to do due to being a permanent slab ( my deck and Dome can easily be dismantled and relocated if needed in the future ) and Iím a long way from the road for a cement mixer to pull up and pour into wheelbarrows which would have to pushed up a steep driveway or concrete pump etc..$$$ it would have been a hand mix and pour job ( pain in the butt )
A 100mm slab would have flooded as well due to the deluge
The deck was the best solution and still is , just have to seal and waterproof the deck
me too

http://www.iceinspace.com.au/forum/s...d.php?t=141024
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Old 09-05-2021, 09:21 PM
Startrek (Martin)
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Originally Posted by xelasnave View Post
Hi Martin...this wont sound crazy if you think about it for longer than the time it takes to dismiss it out of hand....get a tarp that covers the lot to ground level...you need not have it on most of the time but when it is clear you are in for a week of rain cover the lot...the dome and deck...I say this because I bet it is the only way to stop all water in those really wet periods...do all your water proofing for sure..and this approach will allow you to keep your carpet tiles...think about it..piece of mind for under $100...
Alex
Alex
Thanks
Excellent idea
I do have a NexDome tarp but it only covers the Dome ( not the walls down to the ground )
If I can seal the deck ďproperlyĒ, it will keep the floor inside relatively dry even through periods of rain like last week
Cheers
Martin
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Old 12-05-2021, 12:10 PM
ad602000 (Pete)
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damp observatory

Quote:
The deck was the best solution and still is , just have to seal and waterproof the deck
could you not make a floor on the deck from the waterproof board used in showers and bathrooms and then use the same waterproof paint on goop used to put on that board to seal and waterproof it and instead of wall /floor tiles as is the practice in bathrooms use carpet squares. It wont let water in if done properly.
the tiny gap I had between walls and slab leaked but not after I applied the above, its also quiet paintable.
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Old 12-05-2021, 03:24 PM
Startrek (Martin)
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Originally Posted by ad602000 View Post
could you not make a floor on the deck from the waterproof board used in showers and bathrooms and then use the same waterproof paint on goop used to put on that board to seal and waterproof it and instead of wall /floor tiles as is the practice in bathrooms use carpet squares. It wont let water in if done properly.
the tiny gap I had between walls and slab leaked but not after I applied the above, its also quiet paintable.

Thanks for the suggestion
After the rain stopped the floor deck boards dried out in a day ( 8 to 10 inches of rain in 3 days doesnít happen every week ( maybe once or twice a year here )
Iím thinking of leaving the floor ( just deck boards ) as is but just reseal the Dome base inside and out properly and a coat or two of bondcrete
If I lay a completely water proof membrane floor like a shower it reduces my ventilation and in summer the Dome will be like a sauna
The main thing is all my gear is dry , thatís the main objective I think
Thanks
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Old 13-05-2021, 10:38 PM
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muletopia (Chris)
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eva tiles and under

Hello Martin,
I have the interlocking EVA tiles on my 2.3M Sirius ob, and as you said I have the tiles to about 25 mm from the wall.

The ob is bolted to a concrete floor and the tiles sit on interlocking plastic grating about 30 mm deep which in turn sit on the concrete floor. The floor has drainage channels cast in it. As dehumidifier I have two pots of Zilch as I do not have mains power at the ob. I have never had a wet floor with this arrangement.

This has kept my permanently mounted scope dry and mould free for some years. I must say though that as a precaution I keep my eyepieces in as sealed plastic container with silica gel sachets.



Just my experience
Chris
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Old 14-05-2021, 07:37 AM
Startrek (Martin)
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Originally Posted by muletopia View Post
Hello Martin,
I have the interlocking EVA tiles on my 2.3M Sirius ob, and as you said I have the tiles to about 25 mm from the wall.

The ob is bolted to a concrete floor and the tiles sit on interlocking plastic grating about 30 mm deep which in turn sit on the concrete floor. The floor has drainage channels cast in it. As dehumidifier I have two pots of Zilch as I do not have mains power at the ob. I have never had a wet floor with this arrangement.

This has kept my permanently mounted scope dry and mould free for some years. I must say though that as a precaution I keep my eyepieces in as sealed plastic container with silica gel sachets.



Just my experience
Chris
Chris,
Thanks
Sounds like a well thought out interesting design that works well for you
Cheers
Martin
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Old 12-06-2021, 02:34 PM
SteveJP (Steve)
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Dehumidifier recommendations

Hi,
I wonder if anyone can recommend a dehumidifier suitable for a NexDome?
Ideally
  • Power consumption in range 50-100W (240VAC)
  • Has a drain - or can have DIY drain fitted
  • Not requiring button presses to turn on, so it can be remotely or automatically turned on with just control of A/C power.

Thanks
Steve
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Old 12-06-2021, 06:49 PM
glend (Glen)
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Steve, I have burned out two of the cheaper ones available on the Net, they both failed where the power cord enters the unit, melted stuff. So look for ones suitable for continuous duty, and they are not cheap.
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