Dew - and What Do You Do with it?

[ve1drg]

I was out last night and found the DEW was terribly heavy.  I had put a small towel down on a table and noticed that within about 30 mins  it was soaking wet.

My question is -  how do observers handle heavy dew?    I mean it gets on your book,  your equipment, chairs etc.. ..   Do you just cover things with plastic or something?  My books got soaked so that was the end of my notes.

I presume with such DEW that your lenses will be covered too.  I have a lense-dew heater but never used it.  But maybe tonight I will give that a try.  Things still looked pretty good without it.

So - what do we do?  Just live with the wet dew on everything - or keep things covered?

[swamp thing]

My star atlas is laminated. I keep my eyepieces in the case when not being used and keep dew caps on the finder between uses.

The secondary of my 10" has dewed up once in four years, so no great concern there. My larger scope I reckon on fitting a dew heater for the secondary, that will take care of that. I always carry my 12v hair dryer for emergencies.

[AlexB67]

There was a thread on the topic quite recently, perhaps it'll help you.

http://stargazerslounge.com/topic/194121-dew/

[bingevader]

I try to laminate any sheets I use for observing.

My EPs go in small neoprene bags and hang of the EP rack.

Cheers

[kerrylewis]

I've bought a laminator for charts and lists - they are quite cheap in this country £25 for an A3 unit. I then use a marker pen which works on the laminate for notes etc.

Not sure what scope you have but I found within days that my SCT had to have a heated dew shield. I keep the eyepieces a case until I use them and I've just bought a heated strip for them too.

I have made a dew shield for my Telrad - details available on the internet.

Certain times of the year are going to be worse than others - and I don't think you can beat the dreaded dew, just do your best to combat it.

Kerry

[LukeSkywatcher]

I basically observe with 8" Go-To SCT and an 8-24mm zoom EP. I do have a dew strap for the scope,so dew is not something i worry about much. Although the SCT is a dew magnet. I used to take books etc out with me when i used different scopes but over the yrs have refined the gear i take out with me because i am in a wheelchair and both my hands are needed to steer the chair,so the less gear the better as it means less trips indoors.

[ve1drg]

Thanks guys for your input.  I think the bottom line is that I have to refine what I am doing.  And of course others have done that so I know I can do the same. 

It was sure a great viewing night last night but couldn't remember when we have had that much dew.  What a life, eh?

Well cheers all and thanks for the input..

[Quatermass]

The last two years all I have ever used is a small hairdryer and some kitchen roll to wipe the secondary mirror now and then. A towel over the laptop soaks up any dew before it gets too bad. Now OK have built an observatory though so not such an issue.

cloud cloud go away come again another day

[Lorne]

Ted,

I don't suppose you will have this problem in Florida, but over here in the colder months the dew turns to frost, its common to have a layer of ice on my scope, secondary mirror and my laminated charts stuck together. A 12v hair dryer should really be my next buy 

[MarkMittlesteadt]

I always use dew shields and dew heaters on all the optical parts. They don't require much power to operate, even all night long.

I mostly use a 8-24 Zoom EP (with a 1.25 dew heater on it), but my other EP's as well as charts, flashlights, etc. are all stored either in my scope case (when the scope is mounted on the tripod) or in a small case I made for under the tripod. 

Optics are ALWAYS dew free, and everything else I want dry is too. The rest? Sometimes its wet, but it gets wiped down a bit if really bad and brought inside to air dry.

[AndyWB]

I got some sticky back sheet plastic to cover my books - which helps. I also got a waterproof bag like this one and I just try to keep the books in it. It's a lovely bag - it can be (and often is) dripping wet outside, still dry inside.

I'm still working on a solution to dew on the secondary, though. I'm thinking maybe a hairdryer - but the battery to supply one is a lot of money relative to the cost of my scope.

[acey]

Dew occurs on surfaces exposed to the clear sky, and the more horizontal they are (i.e. the more exposed to sky), the more they dew. I keep books covered when not in use, and I keep my charts vertical on a heavy-duty music stand. With the field version of SkyAtlas 2000 and with Uranometria I never found dew a problem - both are printed on heavy stock and if they get a bit moist in use they just dry out afterwards. With my Great Atlas Of The Sky the charts are glossy and probably dew-proof but I put individual charts behind a plastic sheet from a clip frame, and just wipe the dew off that at regular intervals. My S&T Pocket Atlas has got very damp on occasion but it's done it no harm. These things are all made for field use - I'm a bit more careful with things like my NGC/IC Photographic Atlas which is on finer paper.

I use a dewshield made of camping mat for my scope, and a cardboard one for my finder. I keep eyepieces capped when not in use. If the scope is unused for a while I tilt it down or cap it rather than leave it pointing at the sky. If the optics do happen to dew I give them a blast with a hairdryer - moving air is enough to do the trick so a hot setting is not necessary (and would somewhat negate all that time you waited for the mirrors to cool to ambient temperature).