Bringing a cold scope inside?

[Stargazer33]

Hi, I hope I am not re-asking an obvious question - I did do a search but came up with nothing - so here goes.

What is the best way for bringing a cold scope back into a centrally heated house?

I am worried about the mirroring getting damaged due to dew constantly forming on the mirrored surfaces (I assume that they are mirrored on the front of the glass).

Do you put the caps on outside and then bring the scope inside, or do you leave the caps off, let the lenses condense and then dry and finally clean them up before putting the caps on?

I have made myself a dew shield from an A3 laminate sheet (put through the laminator with nothing inside) with black velveteen material stuck to the inside and then held around the scope with Velcro. This works very well whilst outside but is obviously no good once the scope comes inside.

BTW, I cannot turn the central heating off before I bring the scope inside - my wife doesn't do cold!

Thanks for any help,

Bryan

[Carbon Brush]

If you have a secure cold place (garage or shed) there is nothing wrong with leaving the scope there.

If you cap the scope, the relatively dry air in there won't condense as it warms. If you bring it inside uncapped, the warm very moist air will condense.

If you get condensation, you can quickly warm up & dry the entire scope and glass using a hair dryer.

If you leave the condensation, angle the scope so drips come off easily, rather than pooling on the mirror. No real harm done here.

[Stargazer33]

Thanks for that, I wasn't sure if it was condensing under the caps and just trapping the moisture in there rather than letting it evaporate.

Unfortunately I haven't got anywhere unheated that I can store the scope safely. Would love to build myself an observatory, but I don't think the fish will give up the prime spot in the garden!

Caps on in future!

[AWR]

I cap mine before I bring it back in and resist any temptation to remove the caps (even for a second) until the scope is fully warmed up. Other people have success with other strategies but this one seems to work for me.

Andrew

[Flaxinator]

When i bring mine back inside, the cap is on, whenever i have checked the mirror after it has been inside for a while, the mirror looks slighty fogged but soon dries off, never had any serious condensation like you do on the outside of the scope.

[Stargazer33]

Definitely looks like caps on outside then!

Thanks for the help guys.

All I need now is a clear evening and for this damn wind to drop.

The odd fist sized meteor would be nice too!

Thanks again for the advice.

Regards,

Bryan

[Kit-Fox]

I always bring mine in uncapped and leave the caps off over night.

The scope is left lying down on the floor on its side in the hallway ( the coldest part of the house even with central heating )

In the morning its moved to the spare room to get some sun and then when its had a chance to warm up a little the caps go on

[Monki]

I keep my refractor pointed down and cap it outside with a silica gel stuck inside the cap, to help soak up moisture. I guess this isnt as easy to do with a reflector though

Sent from a Galaxy S 2 far away.

[jfox61]

I always bring mine in uncapped and let any dew dissipate naturally, reflector upright, mirror to the bottom to let heat and moisture rise. Refractor, I take off the eyepiece to let the tube "breathe" and again just leave it to dry naturally. This normally takes around 20 minutes for the lenses to dry then I cover the lenses. I wipe the tubes down with a teatowel. Whatever you do, don't clean the lenses as this will do much more harm than good. As for ep's, again, leave them to dry naturally then cap them.

[Stargazer33]

Thanks for the advise guys. Seems like it is divided 50/50 as to caps on or caps off.

I am worried about drying spots forming on the primary and even secondary mirrors though.

I guess these would have to be professionally cleaned periodically?

I think I will take the star diagonal off when I bring the tube in, to let it dry out easier.

Thanks again for all the help.

Bryan

[KevG]

I always give the ota, a quick de-dewing with a hair dryer when It comes indoors (low setting & not too close), always done the job well & has kept water stains off the objective.

[jonathan]

In case you feel the need to clean a piece of glass, not sure if it's safe for mirrors though:

First Light Optics - Baader Optical Wonder Fluid

I seem to have a couple of water stains on the front of my 8SE SCT, not sure how they got there, but they only ever show up when the glass is dewed up anyway so I'm not too worried that they are there. The Baader wonderfluid didn't remove them, I didn't rub that hard though.

I usually put caps on outside mainly to avoid scratching or touching the glass as I move things indoors, then I release the caps slightly and leave the eyepiece case open to let any moisture evaporate. I will go back to them the next day to put the caps on properly and close the eyepiece case.