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Bringing in Telescope from the Cold...

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#1 SeaDog35

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Posted 22 February 2020 - 07:33 AM

Good Morning All, Had the scope out early this am to check out the planets. It was cold, to us, here in Florida, 54 degrees. Yes, I know, that's funny, to a lot of you folks. I was wondering is there anything to know about bringing in the scope from the cold outside. Precautions? 



#2 cookjaiii

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Posted 22 February 2020 - 07:54 AM

Wrap it in a vapor barrier (e.g., case or plastic bag) before you bring it inside.  Bring it in and let it warm up thoroughly before opening it up inside.  After a couple hours, you can open the vapor barrier and let any residual condensation dry out.

 

You just want to avoid having moisture from the inside air condense on the cold surfaces of your equipment.

 

Keep in mind that moving outside from a warm humid environment to a cold outside environment can cause condensation inside your OTA, so it's good to store your OTA in a vapor barrier with silica packets.

 

Your temperature differentials are minor compared to what us northerners face, so this advice may be overkill, but then again, we may not have the same high humidity you have there in Florida.


Edited by cookjaiii, 22 February 2020 - 07:55 AM.


#3 mac57

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Posted 22 February 2020 - 07:57 AM

Put your caps on before bringing in your scope.  The house will be much more humid than outdoors and dew will form on the optics.  Same goes for eyepieces.  


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#4 MalVeauX

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Posted 22 February 2020 - 08:44 AM

Good Morning All, Had the scope out early this am to check out the planets. It was cold, to us, here in Florida, 54 degrees. Yes, I know, that's funny, to a lot of you folks. I was wondering is there anything to know about bringing in the scope from the cold outside. Precautions? 

Nothing to worry about...

 

Dew forms when the surface is significantly colder than ambient and the dew point is based on humidity, which here in Florida, from 11pm to 6am is essentially 99% humidty, so the dew point is ambient temperature essentially. Having your scope out in the cold, and coming into your warmer home, it will likely form condensation when you come inside, if the humidity in your home is also high, but once the temperature acclimates, it'll stop. The only thing to perhaps watch for is that if water condenses on your optics and evaporates there, it may leave behind some residue, but nothing damaging, just something to clean every now and then.

 

Here in Florida it's usually the other way around though. We take our stuff from our cooler air conditioned homes out into the hot humid ambient and our stuff gets fog/dew just by going outside :p

 

Very best,


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#5 junomike

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Posted 22 February 2020 - 08:46 AM

I cap my OTA's and place them in the case (if applicable). IME the larger Newts rarely (If ever) Dew over as opposed to a Refractor or SCT.


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#6 star drop

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Posted 22 February 2020 - 08:58 AM

Is there a possibility of storing your telescope in a shed outside?



#7 John Fitzgerald

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Posted 22 February 2020 - 08:59 AM

Cap them, wrap in plastic vapor barrier, then in a blanket.  Bring inside, and don't uncover until a few hours later, and then make sure it is all dry.



#8 John Fitzgerald

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Posted 22 February 2020 - 09:03 AM

Put your caps on before bringing in your scope.  The house will be much more humid than outdoors and dew will form on the optics.  Same goes for eyepieces.  

Cold optics will likely have temperatures below the inside dew point, and moisture will condense on them.  Covering with airtight barrier is very important. Let them warm slowly also.



#9 SeaDog35

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Posted 22 February 2020 - 09:27 AM

That all makes sense. Pretty much what I did. Capped all eyepieces and put a sheet over the OTA. Now, as MalVeauX mentioned, taking the scope out from the air conditioned, 73 degree, low humidity, house, out into 78 degrees and 85 % humidity, that's another problem. For night viewing I have been taking scope out , on carport and covering with sheet, turning fan on and waiting 1-2 hrs before viewing. Any thoughts on that? 



#10 Tony Flanders

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Posted 22 February 2020 - 11:38 AM

That all makes sense. Pretty much what I did. Capped all eyepieces and put a sheet over the OTA.


A sheet doesn't cut it. You need a completely sealed environment. For a Dob, make sure that both the front and rear ends of the tube are sealed. When in doubt, the traditional solution is to use shower caps. As long as the tube is sealed inside, it makes no difference if it collects a little condensation on the outside.
 

Now, as MalVeauX mentioned, taking the scope out from the air conditioned, 73 degree, low humidity, house, out into 78 degrees and 85 % humidity, that's another problem. For night viewing I have been taking scope out , on carport and covering with sheet, turning fan on and waiting 1-2 hrs before viewing. Any thoughts on that?


You could keep the thermostat at 80 and use fans to keep yourself cool. Save lots of money, too.

The only alternative is to do the bring-inside routine in reverse. Bring the scope outside fully sealed, and don't use it until it has reached ambient temperature. Or apply heat, such as a hair drier, to expedite the process. Or use a staging area such as a garage where it can warm up unattended without worry about theft.



#11 ascii

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Posted 22 February 2020 - 02:04 PM

In Florida, I haven't experienced much more than a light fogging of my scope's exterior upon bringing it in on a cold (by Florida standards) night.  Keeping all of my exposed optical surfaces and scope openings well capped until it reaches ambient has been sufficient.  I've never seen any evidence of condensation or its residue on my optics later on.

 

Summer has been another matter, as other Floridians have mentioned.

 

My wife likes it quite cool in the house.  We sometimes get summer dew points up into the low 80's Fahrenheit.  There has been more than one occasion where large amounts of condensation have formed on the scope when I place it outside to warm up.  There was enough condensation for large drops to fall and splatter on the porch floor.  I've used towels to dry it and a hair drier to gently warm it up.  Even then, just keeping the optics capped was sufficient.  Anyway, that's been my experience with my Maks and refractors.  I have no experience with other types of scopes in this environment.

 

Also, the summer temperature and dew point in most Florida garages will be little different than they are outdoors.



#12 SeaDog35

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Posted 22 February 2020 - 03:37 PM

I'll go set some shower caps. As for setting the thermostat to 80 and turning the fans on, I'm thinking not, Mr Tony. We could do it, if we had to. We get uncomfortable at 76 degrees. I know, we are sissies. I'll do the shower caps and I have some really huge plastic lawn bags that I'm sure will cover it, maybe try one of those. I only have a carport. I have a 20 ft container out back, for storage, I could put it in there. But , it gets hot in the summer. I can see an 8ft square observatory, in my future. Maybe 10ft. Probably put one together for cheap enough. Next year maybe. Thank You, Gentlemen



#13 John Fitzgerald

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Posted 22 February 2020 - 07:16 PM

We keep the house at 77 to 78 in the summer.  I still frequently get condensation when moving things outside after sunset.   If I put them out a couple of hours before sunset, it doesn't usually happen. 



#14 thomasr

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Posted 22 February 2020 - 08:55 PM

Even if you drape a simple fleece throw over the OTA when you first bring the telescope indoors, it will:
1) act as a temperature buffer to prevent flash condensation on the cold metal surface, and
2) quickly wick away any moisture that does form

Sent from my LM-G820 using Tapatalk

Edited by thomasr, 22 February 2020 - 08:55 PM.


#15 clintmk89

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Posted 22 February 2020 - 11:59 PM

Glad this got brought up, had my Z8 dob get pretty damp when I brought it inside the house (70F) from outside (33/35F). I wasn’t to sure if I did the right thing by opening it up and aiming it downwards. Guess for next time I’ll put the shower caps back on both ends and let it sit for a bit still aimed down before I open it up.

#16 phillip

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Posted 24 February 2020 - 02:58 PM

Won't be the correct choice for all, but I've enjoyed simply keeping the XT8 Dob in trunk of my car. Always thermal ready.

 

I don't find alignment much of an issue, tho needed same as when it was taken in and out of doors. 

 

Worked great for me over the years..

 

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#17 Mbinoc

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Posted 26 February 2020 - 01:20 PM

Good Question, after seeing the replies I realised that what I have been doing is all wrong.

 

I have been bringing in my telescopes un-capped and pointed downwards thinking I should let them thoughly dry off before re-capping.


Edited by Mbinoc, 26 February 2020 - 01:21 PM.


#18 Frisky

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Posted 26 February 2020 - 01:34 PM

Just a note on what I do, and I'll soon be the world record holder for observing in the cold frequency. I take my scope back into the house and put it back on the tripod and let everything sit there until there's no sign of it being steamed up. About 15 to 20 minutes. Then, I cap it up and it's as good as new the next time out. I've done this over 600 times, and it's always colder outside than inside. I've done it at 73 degrees inside and minus 24 outside! No problems! This business of babying a scope and eyepieces is for the birds.

 

Joe



#19 laedco58

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Posted 26 February 2020 - 01:43 PM

My Z-12 isn’t house broke. It lives in a unheated shed. Al Nagler told me no harm would come to my NP 127 as long as it was dry, if I capped it and returned it to its case before bringing it in the house. My SV80A gets capped and brought in, but lives on its mount.



#20 ascii

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Posted 26 February 2020 - 02:00 PM

Lots of great advice about capping the scope before bringing it inside, except for those times when it is exactly the wrong thing to do.

 

On hot humid nights you should leave the scope uncapped when bringing it inside.  You don't want to trap hot humid air inside the scope and bring it into an air conditioned house.  You'd end up with puddles of water condensing and getting trapped inside the scope for who knows how long.  Wait for it to cool and dry off before capping.



#21 Don W

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Posted 26 February 2020 - 02:11 PM

I never cover a scope that I bring in from the outside. Just let it warm up and any condensation that forms will evaporate.


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#22 mac57

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Posted 26 February 2020 - 02:50 PM

SeaDog35-Be careful of salt residue, as you are so close to the coast.  Salt is not your friend.  I'm suffering with you, being in DeLand.  Have a blast, Mark



#23 laedco58

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Posted 26 February 2020 - 03:39 PM

Lots of great advice about capping the scope before bringing it inside, except for those times when it is exactly the wrong thing to do.

 

On hot humid nights you should leave the scope uncapped when bringing it inside.  You don't want to trap hot humid air inside the scope and bring it into an air conditioned house.  You'd end up with puddles of water condensing and getting trapped inside the scope for who knows how long.  Wait for it to cool and dry off before capping.

What is this air conditioning you type of?



#24 Frisky

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Posted 27 February 2020 - 01:54 AM

Don W. has it right. Bring the scope inside, let the condensation evaporate. Just takes 15 minutes or so, and cap it and the eyepieces. 

 

Joe



#25 Sketcher

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Posted 27 February 2020 - 05:09 PM

I was wondering is there anything to know about bringing in the scope from the cold outside. Precautions? 

Yes, there are things you should know about:

 

If moisture is permitted to dry on (evaporate from) an optical surface, one will end up with material (water spots) being deposited on that optical surface.  Now, some people don't consider this to be anything to be concerned about and just go ahead and allow these deposits to build up on their optics.  There are others who also show little concern, but prefer to frequently clean the deposits from their optics.  Still others employ preventive measures, and don't allow moisture to condense on their optics in the first place -- alleviating the need for frequent (or in some cases, even much rarer) cleanings.  There are those in the second group who will "cringe" at the thought of keeping one's optics so pristine as to not require any regular cleanings; but that's their problem.

 

Another concern for some (there are always some who couldn't care less) is moisture ending up inside one's optical tube assemblies.  This can cause thin, smoke-like films to develop on inside surfaces or, in extreme cases, water-spots.  This can be a bit more difficult to remedy, so some of those who permit this to occur don't try.  One solution that one occasionally sees is the selling of the telescope before the problem gets to be overly obvious.  But as with external water-spots, this also is preventable.

 

And finally, there's moisture that ends up being trapped inside an OTA or between optical elements for a long enough period of time for itty-bitty living organisms to grow, multiply, and, in some cases, eventually eat away at some of the glass.

 

So, those are some things that one ought to be aware of.

 

Precautions?

 

Well, as we've seen in some of the responses, some people don't bother with taking any precautions.  I have precautions that I take; but mine aren't very popular (I've shared some in the past -- learned my lesson) so I'll just say, if you're interested in taking preventive measures, look into how and under what conditions moisture condensation on optics takes place.  How can moisture get inside my OTA? etc.  Once you understand that, you're well on your way to discovering what can be .done in your area, and with your equipment, in the way of prevention.  Or, of course, you can ask here and get most any response imaginable from all of our supremely knowledgeable experts   Oh, I forgot.  You did ask here!

 

OK, so the most fool-proof (or extreme) precaution is to not allow moisture to condense on your optical surfaces nor inside your optical tube assemblies.  You want to avoid sealing a telescope and putting it away (especially within any air-tight container) for any significant period of time (certainly no longer than 24 hours) as long as any trace of moisture remains on or within the telescope.

 

Preventive details are going to vary depending on a variety of factors, such as one's outside conditions, one's inside conditions, one's telescope type, size, etc. one's ingenuity and resourcefulness, the presence or absence of telescope cases, etc.  We don't all handle our equipment in the same ways, nor can we.  So there's going to be a lot of opportunity for different people to do these things in somewhat different ways.  The key is to understand the potential problems, how those problems can occur, and discovering what preventive measures one can take under one's specific circumstances.




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