Hairy Driers

[Star-Gazer]

I just ordered a dew guard from FLO ready for when I go to dark skies in a few days.

I have not had any problems at all so far with dew using the scope at my home at all hours.

I have ordered some micro-fibre cloths to clean any dew off with and to clean the scope lens and EP's generally.

But would it be an advantage for me to get a 12v hairdrier for around £15? Will it do more than the cloths in terms of drying any dew that forms?

Also what advice would anyone give me about spending nearly £100 on a dew guard heating system for the EP and Lens?

ta in advance

[Ad Astra]

The hair dryer is a good option, otherwise a 'dew strip heater' that warms the objective or corrector plate just a degree or two to keep dew from forming.

The advantage of the latter is that it is 'always on', and you needn't worry about it. A hair drier is an "Oh Rats! I have dew!" emergency solution that solves, but does not prevent the problem.

Dan

[ollypenrice]

Yes, get a dew heater strip. I use them straight from 12 volt without costly controllers and have never had an issue.

When imaging a hair drier clears the dew but leaves the scope unfit for use due to thermal effects. When these go the dew is back!

A less aggressive solution is to drape a warm dry towel over the scope, not touching the glass. In a few minutes it will absorb the dew.

Regular wiping, no, absolutely not. In the dark you could easily grind a scratch into your corrector.

Olly

[Star-Gazer]

I didn't realise you could use a strip heater witout a controller....anyone else do this?

[alowen]

I didn't realise you could use a strip heater witout a controller....anyone else do this?

Yes, my dads meade ls6 has recently been fitted with a dew strip. Cigerette fixing into his powertank and bingo. Its been dew free ever since, cant recomend enough.

Al

[ollypenrice]

I didn't realise you could use a strip heater witout a controller....anyone else do this?

Bear in mind that I do this with two mounts/scopes on about two hundred nights a year... If I was going to have burned through an OTA I would have done it by now!

The strips I use are Orion branded ones bought here in France. If you were worried you could always wire them up to a 9 volt supply instead.

Olly

[Slangers]

I had terrible problems with dew when I first got my scope. I got an Orion dew zapper strip. It works brilliantly and I run it off my 12V pack with no need for a controller.

[JamesM]

I would recommend the American made "Dew-Not" brand of dew strap (sole importer - Modern Astronomy) as it's construction uses a lot less current. The reason for mentioning this is that one of the reasons people use a controller, is so that they are able to regulate the current that is drawn by the strap and therefore pull the minimum current required. If you are like me and observe from a remote dark site and therefore need to rely on a battery (as opposed to mains at home) for your power supply, dew heating can take up a lot of juice if you're out all night.

James

[ollypenrice]

I would recommend the American made "Dew-Not" brand of dew strap (sole importer - Modern Astronomy) as it's construction uses a lot less current. The reason for mentioning this is that one of the reasons people use a controller, is so that they are able to regulate the current that is drawn by the strap and therefore pull the minimum current required. If you are like me and observe from a remote dark site and therefore need to rely on a battery (as opposed to mains at home) for your power supply, dew heating can take up a lot of juice if you're out all night.

James

Fair point. I'm on the mains.

Olly