Dew-Not or Kendrick?

[Brinders]

Hello again. Having had my new Celestron C9.25 on the EQ6 Pro mount for a few weeks now, I've realised that on the rare still nights we have had, that dew can become an horrendous problem with such a large corrector plate even with a dew shield in place. I've decided I need some active dew prevention pronto, but since I've already spent more than I originally budgeted on my kit, I'm looking for a budget solution.

The Dew-not 4 channel basic controller at £24 and dew-not 9" heater tape for £33 at Modern Astronomy has caught my eye, or if the basic controller is too basic, then the dual channel PWM controller at £59 might be in the running. Any one know if the Dew-Not system is any good?

Alternatively, I was thinking of the Kendrick standard single channel dew controller at the Widescreen Centre for £60.10 plus the 9-10" heater tape at £49.95.

Any opinions as to which is the better of the two - Dew-Not or Kendrick?

[Brinders]

Hello all :wave:

In the absence of any response to my query regarding the better of the two dew control systems, I have opted for the Dew Not system based largely on positive reviews in the Cloudy Nights forum and elsewhere. The advantages appear to be reduced cost, excellent quality, better and more efficient design of the actual heater tapes compared to the Kendrick. I note the controller looks suspiciously like the Astrozap controller on FLOs sight. So long as it removes the dew and lasts a few years, I'll be happy.

Brinders

[AstroTiger]

i have also been considering making a purchase of such a thing. Mind u first i fear i might need to buy the crayford eyepiece mount first :-(

But if u have bought one, please tell us how it goes with it, if its worth the money

my concern is would it caue turbulance?

i would be most interested

[Brinders]

Hello Alastair,

I ordered the dew not Saturday so expect it will arrive sometime this coming week. I too am a little concerned about the heat creating turbulence, but since my last session had to be cut short because of a terrible build up of dew on the corrector plate a little turbulence would be better than no view at all!

From what I've read both at the manufacturer's site and in the Cloudy Nights Forum, the dew not system is not as power hungry as others and the PWM dual channel controller should allow me to apply only sufficient heat to keep the corrector plate clear thus limiting the amount of in tube air turbulence that might occur (I hope).

I'll let you know how I get along.

Brinders

[Rob]

By all acounts the Dew not has the edge.. Astro zap is also a good product!

[FLO]

As far as heater-strips are concerned, I doubt you will go wrong if you stick with Astrozap, Dewbuster, Dewnot or Kendrick. All claim to have lower power consumption, more efficiency and more even heat distribution than their competitors but as far as I can tell nobody has made a definitive (and independent!) comparison. I would guess that any differences in performance would be quite insignificant.

When comparing controllers it is a different story with Dewbuster and Kendrick clearly leading the way.

... I note the controller looks suspiciously like the Astrozap controller on FLOs sight.

It does rather, doesn't it

[Kai]

I have a Kendrick controller (digifire 7) and i am very happy with it.

[Brinders]

Well I have used the Dew-Not a few times now and I'm very happy with it. It does an admiral job of keeping dew off the corrector plate and I haven't noticed any loss of optical performance through any in tube turbulence. Indeed, if you look at my images of Saturn elsewhere on this site I think you'll agree with my contention.

A concern I have read about previously was the possibility of interference with any cameras attached to the OTA. There hasn't been any either using my DSLR or the security video cam. All in all a great purchase - better than the crayford focuser I bought in the States prior to delivery of my OTA. The Celestron focusing mechanism on the C9.25 is so smooth I'm not sure I really need the Crayford, although thinking about it at high magnifications the image does drop of the laptop screen as the primary mirror moves, but it is easily found again. I think the cost of the Crayford would have been better used for other accessories. Still you live and learn.