Condensation disappointment

Here's the place for any sights you wish to remark on

Moderators: Guy Fennimore, joe, Brian

Post Reply
ThatsMyStar
Posts: 15
Joined: Thu Aug 30, 2007 8:26 am
Contact:

Condensation disappointment

Post by ThatsMyStar »

I went out tonight to do some observing and run in to a problem of condensation on everything. There's me thinking I was doing the correct thing by leaving my scope out for a good hour or 2 only to have my observations cut dramatically short.

So I ask you this, what should I have done taken it out when I was about to use it? Is this common problem and can I have some words of wisdom.

Clear skies everyone.
David Frydman
Posts: 5366
Joined: Mon Jan 18, 2010 9:25 am
Contact:

Post by David Frydman »

It depends on the size and type of scope how much cooling time is needed. Also the temperature difference inside and out.
Sorry you had this problem, which is normal.
Others will comment if you describe the scope.

Regards, David
The Bat
Posts: 309
Joined: Thu Sep 04, 2008 3:36 pm
Location: Gt Dunmow, Essex
Contact:

Post by The Bat »

What sort of scope were you using? Perhaps this is a silly question, but did you leave the dust caps on the scope while it was cooling? I don't uncap anything until I am ready to observe. If your scope is a refractor or SCT or Mak, are you using a dew shield?

My tips would be:

- leave the dust caps on until you are ready to observe
- re-cap eyepieces when you change magnification so that they are not sitting around gathering dew.
- keep eyepieces inside until you are ready to go out. They will be warmer then and will not dew up so rapidly. Some people keep them in their pockets so they stay warm.

Hope that helps,

Rachel
Celestron C8-S XLT
CG5 mount, dual axis motor driven
Imaging Source DFK21AF04.AS camera
North Essex Astronomical Society
ThatsMyStar
Posts: 15
Joined: Thu Aug 30, 2007 8:26 am
Contact:

Post by ThatsMyStar »

I do normally uncap and leave but left cap on last night but I did leave the eye pieces out last night which I don't usually do. Maybe this was the problem.

My scope is a beginner Celestron EQ114 I tried to clean the mirror before I went out last night and think I have scrached it, will this cause much issues? I also looked in to collimation (think thats the correct word) of the scope but seems it was aligned ok.

Glad this scope is my beginner because it has been some what of a badly treated telescope.

I will take your advice onbaord many thanks for replies.

Craig
David Frydman
Posts: 5366
Joined: Mon Jan 18, 2010 9:25 am
Contact:

Post by David Frydman »

Dear Craig,
Try to avoid cleaning the mirror.
It is probably O.K. and even if you scratched it it should be fine.
With a small scope like that I think it should not need much cooling time, perhaps half an hour.
Others will no doubt give good advice.
In fact it might not need a cooling time if you initially use low magnification and then higher magnification as the temperature stabilises.

Others here don't like the idea but I used a small hairdryer making absoloutely sure it is electrically safe.
For a small scope it should need just a short gentle airing.
I used it routinely on large scopes just airing it enough for another 20 minutes observing and repeated.
But it must be safe.

Regards, David
Post Reply