After observing?

[jdg600]

Have just had first light with my new Skyliner 200p (will post a report shortly) but am now wondering wether or not I should cap the scope straight after bringing it indoors. I remember that with my old refractor the advice was to leave the caps off for a while after use so that any dew would not dry on the lenses. Does the same advice hold for a newtonian? and if so how long should I leave it uncapped and should the tube be vertical or horizontal?

As usual, any comments or advice would be much appreciated.

John

[Klesk14]

I'd like to know this too as the winter is approaching. I'm sure it'll follow all telescopes? I'm using a SCT and would take any advice on the idea.

[nightfisher]

its a good idea to leave caps of for a while to let any dew evaporate

[michael.h.f.wilkinson]

I do the same, I simply wait until no dew is visible, and then cap and store the optics (the same holds for the eyepieces). It is a good time to put your observing notes in order, and have a tot of malt whisky to celebrate if things went well, or to console yourself if they did not .

[NGC 1502]

Does the same advice hold for a newtonian? and if so how long should I leave it uncapped and should the tube be vertical or horizontal?

Hi John, what I do is to put the caps on before bringing the scope indoors. If you bring a cold scope uncapped into a warm house, then the optics will become very wet, perhaps even running with moisture if it is a sub zero night. I put the scope into an unheated room overnight (not an option for some I realise) then next morning check for moisture. By then, the scope is at the same temp as the room, and uncapping causes no further condensation on the optics.

I then leave the scope uncapped for at least several hours, to allow any moisture to thoroughly dry out. Storing a damp scope is a very bad idea.

I leave the tube horizontal, that way less dust will settle on the optical parts.

Regards, Ed.

Edit - As well a capping the open end of my Newtonian, I put a shower cap on the mirror end, that way, when brought indoors much less warm air can reach the interior of the tube and dew up the mirrors. Don't forget to plug the focuser as well.