Help with current worst enemy!

[Lynxi]

One thing with stargazing which has officially become my worst enemy, especially at this time of year is the condensing of the cold air. The night starts out find (I usually leave around 30 minutes for my scope to adjust to the temperaturs outside) and a few hours in, the finder scope goes first and I hate having to wipe it because I don't want to knock it out of line with the scope. It doesn't take much longer after that for the scope lense to become impossible to see through and wiping the lense clean doesn't help at all.

I hate weather defeating me but eventually running out of unwet cloths sends me packing and I am curious to how people deal with this? It has officially now come my worst enemy!

[Mr TamiyaCowboy]

One thing with stargazing which has officially become my worst enemy, especially at this time of year is the condensing of the cold air. The night starts out find (I usually leave around 30 minutes for my scope to adjust to the temperaturs outside) and a few hours in, the finder scope goes first and I hate having to wipe it because I don't want to knock it out of line with the scope. It doesn't take much longer after that for the scope lense to become impossible to see through and wiping the lense clean doesn't help at all.

I hate weather defeating me but eventually running out of unwet cloths sends me packing and I am curious to how people deal with this? It has officially now come my worst enemy!

a Dew shield, and/or dew heater .

i have the same problem, and after reading around forum found most are making dew shields to help stop the lens misting over. they fit them to extend the scopes tube i can gather from pictures.

but for me it is not just the mirror. my eyepiece also fogs up and becomes wet from dew. have yet to find a way to stop it.

[rowan46]

most people use a dew shield and or dew bands, which kind of scope do you use? A mak or an sct would certainly benefit from a dew shield. a home made one can be made from an old camping mat which should project about 1.5-2x the apparture. I have never tried dew bands as I'm too cheap but by all accounts they are even better. dew bands can also be fitted to eyepieces.

http://www.firstlightoptics.com/dew-prevention.html

[E621Keith]

You will need a dew shield or a dew heater. These can be purchase from FLO here

First Light Optics - Dew Prevention

The effect of dew varies between different telescope design. As others pointed out, SCT and Mak are the most vulnerable, due to the exposed corrector. This also apply to refractors, but most refractors come with dew shield as standard. I never understood why CAT never come with a dew shield. Newtonian designs is most resistant to dew.

If you scope is a CAT, buy/make it a dew shield. If your scope already has one, or if it is a Newt, then consider getting some dew heater.

[Lynxi]

It's a refractor scope, thanks for the link and help I'll definitely be investing straight away. Thanks for the fast responces also, much appreciated.

[swamp thing]

Hi

You'll find, if you leave the lens caps on in between objects your finder should stay dew free for the duration.

HTH

Regards Steve

[Moonshane]

I made little dew shields for my finders and they work well. put the eye cap on though too and you can usually stay dew free. re the main scope, make a dew shield about twice the length of the aperture so if a 4" scope, make it an 8" dew shield) from camping mat or even black card.

don't leave your scope pointing up when not in use either as this affects the dewing process adversely. I am never keen on heat bands as they mean more wires etc and I am never sure about the effect on the image - although dew has a much worse effect!

you should never wipe optics in the field, especially when wet. with the possible exception of the finder scope. I sometimes find that if you keep them in a foam lined box in the house and then bring them out one at a time, replacing the lid after you swap over, this retains enough heat to prevent as much dewing. if they dew, swap over for a bit.

also a small piece of card (or even your flattened hand) used as a fan can work surprisingly well at removing dew on eyepieces.

[Lynxi]

I never thought about putting the eye caps on the finder between use! That's me being lazy no doubt. The dew shields sound like a good idea and easy enough to sort now to prevent the problem tonight, providing there are clear skies of course.

[M4lcs67]

I use an Astrozap dew sheild and haven't had any probs so far. Looks like you already leave your scope outside for a while to let it cool down.

As far as eyepieces are concerned I was told to keep them in your pockets in order to stop them from fogging up (Just make sure that they are fluff free).

[Lynxi]

Just want to thank everyone who responded here, had two successful nights without having to come in since I took everyones advice here. Came in early tonight with the clouds coming in, but had no problems since (unless the temperature has being warmer!).

[gboulton]

Make your own dew shield and dew heater.

I've made and use both, and can stay out all evening even at 70%+ RH. Spent less than $20 total for the lot.

[proflight2000]

I make my dew sheilds from plastic plant pots, all different sizes and dirt cheap.

[FrankieValley]

Camping mat dew shields will give you longer - http://stargazerslounge.com/1274488-post3.html

A hairdryer is a good solution, or dew strips/heaters.