Dew Solving Solution- Crazy Idea?

[Suzy]

I've been having really bad dew problems this year. My last session didn't even see the scope through it's cool down time even (1 1/2hrs) before it got soaking wet.

Hubby has what he thinks is a brilliant idea that will solve my problems, so I just wanted to know what you'll think.

He suggest a patio heater (run on gas), which (kept at a distance from the scope of course) will warm the scope and me (many of you'll will know how much I hate the cold and no doubt laugh at me ). They're only around $150 and can be multi used obviously for when one does actually have a BBQ .

Though I will be out on the open grass, I worry though that the gas fumes might do something to the mirror.

I'm close to buying one, any thoughts? Crazy idea perhaps?

(I do know about the use of hairdryers and Kendricks by the way as a way of helping dew issues. )

[jjjnettie (Jeanette)]

Why not buy a home brew heating strap to wrap around the base of your OTA?
Using a gas heater will keep you warm too, I know, but think of all the hot air currents, ruining your seeing.

[Liz]

Originally Posted by Suzy

I've been having really bad dew problems this year. My last session didn't even see the scope through it's cool down time even (1 1/2hrs) before it got soaking wet.

)

Come up to TvilleSuzy, and I will show you what real DEW is!!
I am always on the look for something to help, and have recently bought couple of dewythingos from PGC Hunter.

Not sure about the patio heater, it would need to be very close to scope, and dont they emit a little light?

Hmm.... Home brew heating strip sounds an idea.

Hairdyer was useless up here on Saturday night - was just a little cheapy Repco one though, with not much power.

[multiweb (Marc)]

Originally Posted by Liz

Hmm.... Home brew heating strip sounds an idea.

Yeah I've been making a lot of them this week and also got those JayCar DC motor controllers to regulate. It passes the time while it's raining Done some for my ED80, newt and even a small fat one for my pentax lens. PM me if you want details. It's really easy to make them.

[Astroman (Andrew Wall)]

Originally Posted by multiweb

Yeah I've been making a lot of them this week and also got those JayCar DC motor controllers to regulate. It passes the time while it's raining Done some for my ED80, newt and even a small fat one for my pentax lens. PM me if you want details. It's really easy to make them.

I agree easy to make and even better if you know someone who will do it for you.. Done my 17-40mm lens and my 80mm scope...

Too bad electric blankets and moisture DON'T mix

[thunderchildobs]

Many years ago I saw Gregg Thompson (of the Supernova search charts fame) start I small fire and placed a large rock it. He then place the hot rock in the rocker box of his dob to stop his mirror dewing up.

Brendan

[multiweb (Marc)]

Hi Suzy, Liz and others. Here' a quick recap on how I did mine. You will need the following.

• Nichrome wire (comes in 4m) (Jaycar)
• Controller Kit KC5225 (Jaycar) - optional
• Electrical tape 50mm wide (Bunnings)
• Velcro Hook & Loop tape 25mm (Bunnings)
• Weather strip rubber foam 25mm (Bunnings)

First you need to cut a length of nichrome wire. I use about 40-50cm for my ED80. That gives me the right temperature when I plug it in a 12V power pack or battery. Might want shorter length if you want it hotter.

Bend the wire in a square wave form to match the surface you want to warm up making sure you don't cross wires or short circuit the length.

Lay your electrical tape flat on the table and position your bent nichrome pattern. Then stick a layer of foam on top. You then stick the velcro (loop) on top of the foam so you end up with layers like the two illustrations. Just stick some extra velcro (hook) on the end to make an extra length to close the strap et voila!

I find the square patterns best because it springs when you bend the strap into various radii, it's not stiff and it doesn't short. Trust me it goes red in no time when it shorts and gets into one's finger like butter.

The controller is a straight kit from Jaycar. You only need it if you want some kind of regulation (i.e. it's too hot and you want to bring the voltage down).

This is a very easy way of treating dew problems. It's not expensive and it is quite efficient. Hope this helps.

[blindman]

I usually use huge fan to blow away all dew - custom made 1m diameter.
Not sure about heater.
Cheers

[mikerr (Michael)]

I get the feeling that some here might think that dew falls onto there vulnerable surface rather than forming due to small temperature differences.

This article gives a good insight and may change the way we try to battle the beast!

http://www.astro-tom.com/tips_and_advice/dewing.htm

It was interesting to see the two different interpretations of the expression "Homebrew" by jjjnettie and Astroman.

Rgds

Michael

[jjjnettie (Jeanette)]

It was interesting to see the two different interpretations of the expression "Homebrew" by jjjnettie and Astroman.

I noticed that too. I naturally meant the alcoholic sort.

[AstralTraveller (David)]

Susy, I wouldn't touch a patio heater with a barge pole. Too many -ve's and not enough +ve's (maybe none).

Deal with 'cold' with adequate clothes. Either layers and layers or visit the owl. (Brisbane cold??? )

I've seriously considered heater strips but so far have avoided the need, even on the refractor. Don't underestimate the usefulness of passive devices. I have a pair of 15x80 binos which I used to use a lot mounted on an observing chair. They would dew up as soon as you looked sideways at them. I covered them in heavy Al foil (silver emits less radiation than black and hence cools slower) and made dew caps about 15cm long out of heavy foil and bits of tin can, painted black on the inside. Unless l leave them parked near the zenith I never have any dew.

Most of my scopes are gotos so the finders don't worry me. Eyepieces and the small binos are the main problem. I find that so long as every item that is not in use is under cover or in my dust and lint-free pockets I have no problems. On the 40cm dobs I sometimes have to cup my hands on the secondary holder for a couple of minutes but that's it.

[jjjnettie (Jeanette)]

Originally Posted by AstralTraveller

Deal with 'cold' with adequate clothes. Either layers and layers or visit the owl. (Brisbane cold??? )

Our Suzy doesn't have an ounce of natural insulation. She feels the cold dreadfully.
I agree, she needs to visit the Owl.

[scagman (John)]

Hi Suzy,

I wouldn't recomend the patio heater. We have one and find it is useless unless you are standing within 2' of it. Most of the heat will go straight up and they are not cheap to run. Using it outside in an open area was totally useless unless you can set up on top of it, using it in a big shed was a little better.

I would go thru a bottle of gas in about 8-10hrs (2 nights usage).

I have attached a pic of what ours looks like. If you dug a hole and put the bottom section in the ground(this is where the bottle sits and doesnt put out any heat) so that the flue is a lot lower then you would be able to sit next to it and enjoy the heat otherwise you would need to stand next to it but from the waist down doesn't get any heat.

I too really hate the cold and found that this solution as a heater was to be a waste of money.
This type doesn't put out any light except from a small hole near the bottom of the flu section but would be minute and could be pointed in the op. direction.
Just my 2c worth.

John

[spearo (Frank)]

Cool
thanks Marc
frank

Originally Posted by multiweb

Hi Suzy, Liz and others. Here' a quick recap on how I did mine. You will need the following.

• Nichrome wire (comes in 4m) (Jaycar)
• Controller Kit KC5225 (Jaycar) - optional
• Electrical tape 50mm wide (Bunnings)
• Velcro Hook & Loop tape 25mm (Bunnings)
• Weather strip rubber foam 25mm (Bunnings)

First you need to cut a length of nichrome wire. I use about 40-50cm for my ED80. That gives me the right temperature when I plug it in a 12V power pack or battery. Might want shorter length if you want it hotter.

Bend the wire in a square wave form to match the surface you want to warm up making sure you don't cross wires or short circuit the length.

Lay your electrical tape flat on the table and position your bent nichrome pattern. Then stick a layer of foam on top. You then stick the velcro (loop) on top of the foam so you end up with layers like the two illustrations. Just stick some extra velcro (hook) on the end to make an extra length to close the strap et voila!

I find the square patterns best because it springs when you bend the strap into various radii, it's not stiff and it doesn't short. Trust me it goes red in no time when it shorts and gets into one's finger like butter.

The controller is a straight kit from Jaycar. You only need it if you want some kind of regulation (i.e. it's too hot and you want to bring the voltage down).

This is a very easy way of treating dew problems. It's not expensive and it is quite efficient. Hope this helps.

[Jen]

yes the battle of the dew grrrr
My secondary mirror and the eyepieces dew up within the hour lately
What about those column oil heaters that would work better than those gas things wouldnt they? (im not sure how much power they use though )
Marc they sound like a great idea if someone actually knew what they were doing to make these haha how much would you charge us lovely IIS ladies to make some of these

[Suzy]

Many thanks everyone for your helpful input, I really do appreciate it.

So it seems the patio heater is out of the question. I did have concerns about it affecting the seeing and raised it with hubby, but he thought it might be okay if I had it at the back of the scope and not use it while it's windy. I wasn't convinced, that's why I wanted to run it past you'll.
As for keeping me warm, I know, some may laugh, but it was more for the dew than the priority of keeping me warm, really (i think? ) ,tho was a nice added bonus.

Marc, thank you so much for the trouble you went to tell us about that nifty dew solution. I'm sure it will help many people reading this thread that are in the same situation as I. Unfortunately, I'm no good at that sort of thing and hubby has his plate full with renovating our home. So I'm with Jen, if you are willing to help us IIS ladies out by selling them to us- we would be incredibly grateful astro chicks . And I'll stay tough, without the heat.

Regarding the freezer suit: Hubby has a freezer jacket that I've tried but it doesn't keep me warm enough, so I've stuck with layers which works for me. I also find it a bit stiff and uncomfy... I like soft and fluffy... I'm such a girl...I know, I know... And I have nothing to lose now by adding that yellow's not my colour either .
..and why did I just admit all that .

Again, many thanks everyone.

[Liz]

Originally Posted by jjjnettie

It was interesting to see the two different interpretations of the expression "Homebrew" by jjjnettie and Astroman.

I noticed that too. I naturally meant the alcoholic sort.

ah, do the homebrew kits have heating straps?

[jjjnettie (Jeanette)]

Yes they do.
They're designed to wrap around a 25lt carboy so they should fit a 10" or 12" ota.
They cost around about $40.

[pgc hunter]

I'm thinking things like patio heaters would stuff up the local seeing big time.

Maybe make a shield that extends out from the front of the scope, I had one on my 10" dob and it worked perfect.

[Suzy]

Hmmm... I really like this solution Sab.
Did you make it yourself, if so what and where did you get the material from? Or did you buy it?