Worst dew ever

[russ]

Setup all 3 scopes yesterday evening. Thought i would take a look at Jupiter and some DSO in the evening and then go for an early start the next morning.

By 7.30pm all 3 scopes were drenched. May as well got the hose out and poured gallons on water on them. Took the dust cap off the SCT and in the time it took to grab the dew shield the corrector had 100% dew coverage. So grabbed the 12v hairdryer and went to work. Cleared 30% of the corrector and the powertank failed. So that was it for the SCT.

Onto the ED. Dust caps off, moved the finder from the SCT to the ED. Found a bright star, aligned the finder and moved onto Jupiter. Just a dim fuzzy blob:icon_scratch: Looked at the lens, completely gone, absolutely dripping wet. Right, that's the end of the ED. Two scopes down, one to go.

Everything hinged on the 200P! Never dewed up before, so should be okay. Took the dust caps off, swung round to Jupiter and a fuzzy blob again. Secondary mirror completely dewed up.

Gave up for the evening. Put the powertank on charge and try again the next morning.

This morning! Take off dust cap from SCT......excellent, clear corrector Dew heater on max attack. Swing round to Mars and get a nice view at 333x (6mm Ortho). Polar caps nicely seen and some darker markings too. The yellow filter really helps to remove some of the glare and improve the view.

Onto to Saturn........nothing! Looked at the corrector and fully dewed out. Dew deater strap nice and warm but having no effect at all. So out with the 12v hairdryer again. But now i'm really up against it. The sky is brightening fast near Saturn. But the dew is just too bad. After 10mins with the hairdryer i had still only cleared 25% of the corrector and Saturn had gone. So yet again i am beaten by the dew.

There is so much stacked against us with this hobby and some nights are not meant to be

[Ant]

Mmmm sounds like you had fun

I've only ever had a newt dew up once, that was kelling 2007 - the primary dewed up

You are right though, sometimes you have to know when to give up for an evening/morning.

Ant

[russ]

My area suffers with incredibly bad dew. I say this was the worst ever but in reality it was probably merely average. Spend all summer looking forward to the autumn/winter skies but in reality the summer skies are far less hassle (apart from only being able to observe between 12-3am).

Powertank is back on charge as forecast is good again for tonight. Plan B is to get up an hour early, rush out and set the dew strap going at 4.30am. Then come in, get ready, have a cuppa and hopefully by the time i get out there the dew strap will have things under control.

[Ant]

The dew is quite bad at home, as I live on an island in the Thames estuary - we get dew during the day

But the dew shield and straps are going as soon as I set up, without removing the caps, so maybe that helps.

Good luck for tonight. I'll be out, hopefully.

Last night was spectacular - I'd forgotten what a dark sky looked like...

Ant

[russ]

Well just checked the forecast and it's changed. According to Metoffice i now have 100% cloud but Metcheck are still going with 5% cloud all night. So anyones guess.

Good luck for tonight if you get out.

[beamish]

If it makes feel any better Russ, it was approx 97% humidity up here in Yorks too, had quite a battle mesen trying to keep front plate and EP's from getting covered:confused:

[russ]

It's a nightmare John. My problem is i didn't start the dew zapper going early enough. Hopefully i may get a chance to put that right tonight except with the forecasts differing so much i won't know whether to setup or not.

[Rob]

I've seen the dew in your area Russ.. sometimes its just best to cave in!. However in reverse you have some nice skies, and great views to be had... swings and roundabouts my friend. On to the next day!.

Rob

[russ]

Yep, don't think we'll ever forget the dew we had on that cold autumns night back in 2003. Poor old 10" LX200 took a real drenching and Kendrick anti-dew just gave up trying.

Skies can be good, but last night was a write off.

[brianb]

Weds night was really damp, I was swimming but my SCT stayed usable all night due to combimation of heaters (corrector plate, diagonal & eyepiece) and long dew cap. I just cap the finder after aligning because it's essentially redundant ... Nevertheless my 70AH deep cycle battery was just about flat by morning. Had to use a 12V hot air blower on bins & camera to get more than 5 or 10 mins use out of them - kept them inside when not in use.

I'd rather have the dew & clear skies than the damp foggy / cloudy mess that prevented any observing last night.

[DarkerSky]

I think dew was a big problem for lots of people out with their scopes last night in many parts of Britain where it was clear. There is a lot of moisture in the airflow coming into this high pressure system sat over us at the mo, plus the ground is saturated in many places after so much rain recently. Within 2 hours of being out my secondary was fully dewed on my 16"

Tonight will be hit and miss again - the further north and east in the UK you are I think the drier the air and the better your chance of it being clear and less dewey

[MartinB]

What a miserable night. That must have been really frustrating. I know this might sound really stupid but is there any way you could provide some sort of cover for the scope. Don't laugh now but something like a garden parasol might be very helpful in your situation. You don't need to shade the scope from the sky too much to make a significant difference to the dew problem.

I've been amazed at how my dome completely eliminates dew. A friend of mine was telling me recently that his sky pod dome also keeps the dew away and that only covers half the sky.

Just a thought.

[Jupiter Martin]

To totally agree there when I got my scope in they they were drenched. But I did have the best nights viewing Ive ever had so far and was amazed at what I got to see. I even got my go too to work which is the first time since starting.

Hope you have better luck over the weekend.

[russ]

I might give that parasol idea a try. Can't hurt and if nothing else, it will give the neighbours a thoroughly good laugh.

The sky was certainly good though and the view of Mars was a good one, so not wasted.

Will try again tonight hopefully.

[Doc]

It was bad last night Russ. My heaters on the secondary and Telrad work a treat and kept them clear but the scope itself was drenced, and then around midnight it all froze to ice.

[Talitha]

I might give that parasol idea a try. Can't hurt and if nothing else, it will give the neighbours a thoroughly good laugh.

Been using one for a number of years and it definitely works unless the scope is aimed almost straight up. Keeps me dry, too. I use a 6' patio umbrella in a small 'Tiki Torch' stand. They're smaller than the standard sized patio stand but still work well. The dew buildup here gets so bad that it often drips off of the umbrella like raindrops, so be careful of electrical connections and notebooks.

Personally i'm a big fan of using a dew shield in tandem with a dew prevention system. Although the systems aren't cheap, they're worth it because they can save a session. It gets put on the OTA at the beginning of every session, and is plugged into a deep cycle marine battery. Normally the temp indicator is set to keep the corrector plate 5 (F) degrees above air temp and it does just fine. But there's a handful of horrible nights every year when i need to kick it up to almost 15 degrees.. by the sound of it, that's what you had.