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what humidity level for an obsy


iwols

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33 minutes ago, iwols said:

hi all just wondered what level you keep the humidity  at in your obsy,mine is between 50 and 65% but not sure what it should be thanks

My obsy is a 5 foot square, and is roughly around 65-75% humidity, and never had an issue, I also have a 12v 25w heater on the top of the pier which keeps the mount area a little below my quoted figures, that is not 8 hours overnight, when not using, my desiccant dehumidifier is on for just two hours a day, 1 hour in the AM and 1 in the PM, as it’s a desiccant one it works down to 1 degree unlike condensing ones that won’t work well at all below about 15 degrees. 👍🏼

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25 minutes ago, iwols said:

Thanks guys and what do you measure the humidity with please 

I have two of these Bluetooth sensors, and the phone app, tiny little things, one in the obsy and one outside, they are about £30 each on amazon

https://bluemaestro.com/products/tempo-disc-bluetooth-temperature-humidity-sensor-beacon-logger

Edited by Stuart1971
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I keep mine at 60%

You can see from the chart where it was off the first summer and on during the winter.   It's on all the time now as the humidity can be high all year round.

This is my data monitor.  It's been totally reliable for the last two years.  No ongoing costs after buying it apart from 2 aa batteries every 4 months.

 

ObsyChart.png

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This might go against the general consensus,  but with regard to the OP’s question, just how important is keeping an observatory at a constant (low) humidity? I guess that leads to the question how vulnerable is the kit to high humidity and more importantly, condensation. I know my kit can be soaked in moisture after a lengthy imaging session, and so you would like to think that Astro gear would be designed to cope with a moisture laden environment.
I’m sure keeping the kit in a benign controlled environment for as much time as possible will prolong the general as new cosmetic appearance, but what lasting damage is done? I don’t run my dehumidifier 24/7 and after 3 years the kit looks  fine and is still all functioning and there are no blooms or growths on the optics.  I do however, religiously keep the air tight dust caps on the scopes at all times when not in use (~90% of the time). My 7 year old Mesu mount has some slight surface rusting on the 4 screws that secure the Sitech cover but apart from that it looks the same as when it came out of the shipping crate.

As for PC hardware, my laptops and monitor are in an adjacent shed, which is only heated when I’m in it, and they are all still going strong after 3 years.

Modern cars are bristling with sensors, cameras and electronics, but not many of them are kept in an air conditioned garage when not in use.

Ok, for about £6 per month to run the dehumidifier, you can argue why take the chance with all that expensive gear, but in the interests of energy conservation and directing more funds to the Astro spend pot, is their a demonstrable benefit or is it done because it just feels like the right thing to do in these damp islands?

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19 minutes ago, tomato said:

This might go against the general consensus,  but with regard to the OP’s question, just how important is keeping an observatory at a constant (low) humidity? I guess that leads to the question how vulnerable is the kit to high humidity and more importantly, condensation. I know my kit can be soaked in moisture after a lengthy imaging session, and so you would like to think that Astro gear would be designed to cope with a moisture laden environment.
I’m sure keeping the kit in a benign controlled environment for as much time as possible will prolong the general as new cosmetic appearance, but what lasting damage is done? I don’t run my dehumidifier 24/7 and after 3 years the kit looks  fine and is still all functioning and there are no blooms or growths on the optics.  I do however, religiously keep the air tight dust caps on the scopes at all times when not in use (~90% of the time). My 7 year old Mesu mount has some slight surface rusting on the 4 screws that secure the Sitech cover but apart from that it looks the same as when it came out of the shipping crate.

As for PC hardware, my laptops and monitor are in an adjacent shed, which is only heated when I’m in it, and they are all still going strong after 3 years.

Modern cars are bristling with sensors, cameras and electronics, but not many of them are kept in an air conditioned garage when not in use.

Ok, for about £6 per month to run the dehumidifier, you can argue why take the chance with all that expensive gear, but in the interests of energy conservation and directing more funds to the Astro spend pot, is their a demonstrable benefit or is it done because it just feels like the right thing to do in these damp islands?

This is why I just have mine on for a couple of hours per day. It just keeps out below 75% humidity, except after a session, then when I shut the obsy, I run for a few hours to clear any moisture out of the air….

During summer months it’s just not used at all, but I do run a 12v 25w heater on the base of the mount 12 hours a day overnight….this helps a lot and is much cheaper to run that the 300w desiccant dehumidifier….

At the end of the day, air movement plus a bit of heat = no condensation…..

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4 hours ago, tomato said:

This might go against the general consensus,  but with regard to the OP’s question, just how important is keeping an observatory at a constant (low) humidity? I guess that leads to the question how vulnerable is the kit to high humidity and more importantly, condensation. I know my kit can be soaked in moisture after a lengthy imaging session, and so you would like to think that Astro gear would be designed to cope with a moisture laden environment.
I’m sure keeping the kit in a benign controlled environment for as much time as possible will prolong the general as new cosmetic appearance, but what lasting damage is done? I don’t run my dehumidifier 24/7 and after 3 years the kit looks  fine and is still all functioning and there are no blooms or growths on the optics.  I do however, religiously keep the air tight dust caps on the scopes at all times when not in use (~90% of the time). My 7 year old Mesu mount has some slight surface rusting on the 4 screws that secure the Sitech cover but apart from that it looks the same as when it came out of the shipping crate.

As for PC hardware, my laptops and monitor are in an adjacent shed, which is only heated when I’m in it, and they are all still going strong after 3 years.

Modern cars are bristling with sensors, cameras and electronics, but not many of them are kept in an air conditioned garage when not in use.

Ok, for about £6 per month to run the dehumidifier, you can argue why take the chance with all that expensive gear, but in the interests of energy conservation and directing more funds to the Astro spend pot, is their a demonstrable benefit or is it done because it just feels like the right thing to do in these damp islands?

I thinks more the constant dampness that bothers me more than the condensation bit.  I'm happy to see my kit covered in condensation/ice/birdcrap whatever as it means it's getting used.  I'm just not keen on my scopes and cameras sitting in a damp and dark environment 24/7 when not in use.  I think I live in a particularly damp part of the world, and this may possibly different to you.  I'm intimately surrounded by fields and rivers and trees in a rural location (it's not as bad as it sounds!)  In my last observatory (a roll off roof design) screw heads and the EQ6 counterweights and bar started showing signs of rust after 2 years, despite very good airflow.   Given that the dome has much less airflow it felt essential to have a dehumidifier to avoid any damage to future equipment purchases.   I'm not sure about the dustcaps on the scope, surely it will still be damp inside the telescope, as the moisture will get inside and onto the glass?

Anyway it seems to be working as 1.5 years into use of the dome, I've no evidence of rust - its a small price to pay for peace of mind.   I run solar panels and E7 tariff at night so it doesnt really cost me that much in the grand scheme of things.  

 

 

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I agree it’s the sensible thing to do, particularly if the electricity cost is offset in the ways you describe. I note from my humidity logger that peak values tend to occur at the same times of the day, so if you need to make economies, running the dehumidifier on a timer two or four times in a 24 hour period might be the way to go.

Do they have dehumidifiers at Pixel Skies I wonder? Clear skies and no damp to contend with, wouldn’t that be nice? 

Edited by tomato
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well i finished up funnily enough with the elitech temperature and humidity sensor wifi and what a difference it makes to the dehumidifiers built in  controls and the phone app means i can check it anytime without going to the obsy,just hope the controller lasts ,will attach image of before and after fitting the elitech

 

80407943697075813536_All.png.4846d15a58df4164f61aa6ac0f9fd6d9.png

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The humidity question comes down to three effects.

First and most obvious is rust/tarnishing on shiny metal.

Second is allowing (encouraging?) mould growth.
Lenses are the most obvious. But all nooks and crannies where a few dead skin cells or general muck can get left ......

Third is degradation or failure in electronics.

I have plenty of 'no longer bright' metal on tripods, mounts, screws and the like.
On a few scopes I have owned, I have swapped out rusting screws for stainless steel.

I have seen the start of mould on camera lenses unused (but kept in the house) for a long time.

I have seen (in factories) monitors with ice or water behind the front layer due to them not being watertight.
I know in my own obsy that one (standard office type) screen will start to show a vertical stripe if it gets damp. It is fine after warming.

Car electronics is built to a much higher standard than general consumer stuff.
It is generally capable of withstanding temperature extremes, shock and vibration, and adverse electrical events.
The vehicle manufacturers lay down very arduous performance requirements, then the electronics manufacturer must demonstrate compliance.
Think of a coil pack on a petrol engine as a good example. Those things shoved on the end of spark plugs.
Sub zero at engine start. Then at near enough 100C in the journey, then chill after stop, then do it all again. Not to mention the constant vibration from the engine.
They can last the life of the car. We get very good reliablity from car electronics. But this is hard won and costs money.
General consumer products (and I include most scope electronics in this group) are a very different situation.

To mention just one electronic component. The humble multi layer ceramic capacitor.
Anything you own, whether a phone, scope handset, tablet, desk computer, remote control, or car engine control electronics, is full of these.
These are well known to fail after vibration and temperature cycling. It is either mechanical failure, or seals failing allowing moisture and oxygen ingress.
Or you can pay 5x to 10x the price and buy 'automotive' rated parts which have construction differences to overcome the above problems.
These are penny items for the basic specification. In my work the need for reliability far outweighs the pennies.
But if you are making a goto mount on a tight budget, you are counting the pennies.
No prizes for guessing what goes into the average scope mount/handset.

 

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