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Dew control advice


Tweedledee
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Looks like it might be time to invest in some proper dew control instead of messing around with 12v hair dryers.


 


I have no experience of electronic dew control, since I have previously used mechanical dew shields or have been well shielded inside a domed obsy.


 


I am initially concerned with my corrector plate, but need a system that I can easily expand and build on as and when I need to. With my kit, I suspect that I might eventually end up with quite a few wires :o . I already have a big 65AH BAZ battery so that is a good start.


 


Getting the right tackle from day one would be good. Looking on the internet I find various different manufacturers systems, and would be very pleased to be pointed in the right direction with any advice on what you think would best suit my needs.


 


Cheers,


Pete.


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hi Pete,


i use one of these,


http://www.firstlightoptics.com/dew-prevention/hitecastro-four-channel-four-port-dew-controller.html


which work well and has 4 ports which can be controlled individually, then you`ll need the relevent size/length dew tapes to fit your scope, one for your eyepiece might be a good idea, which leaves you with two other ports available for other equipment. 


you can pay alot for some makes of dew controllers i.e. Kendrick and others but it depends on budget but they all do the same thing.


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Thanks Rob.


 


Do you know if I can run more than four heaters from that unit or would I need extra units to do that?


I can foresee a possible need for up to 10 heaters.


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I see it says maximum 5 amps per port, so I presume I could use more than one heater per port provided the total load does not exceed 5 amps.


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I use Kendrick Digifire 7's - I did try other lesser known makes but in the end they either blew up or failed in some way. Never had a problem with the Digifires - they have overload protection and fully adjustable to the temperature - very reliable. 4 ports and two pulse ports that I never use (cos I've no idea what they're for lol).


 


You can split them but I've never had the need for more - one band round the objective, 1 each on eyepiece, finder scope, plus a spare for a fan if using a newt (or secondary heater or Telrad). Totally recommended (by me at least). :)


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Pete.

I have all Kendrick stuff on my OTA. I have the 2 channel 4 port Kendrick dew controller with a 2" ep heater strip, a 2" and a 0.965" dew strip for the finder, a Telrad heater dew strip and Martyn made me a secondary heater. If you notice that is 5 heater strips of a 4 port control box!

Had that set up just under a year with no issues at all.

Like mentioned above, Kendrick is a bit pricey but works.

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I make my own from comax resistance wire and a pulse width modulator kit from maplins. Only had a dew problem once when i forgot to turn them on.

When i had my sct i made a fitted heater from microbore copper tube with the comax running through it. The copper was then formed into a circle and it fitted in the corrector plate flange, this together with a dew seild worked exceptionally well as the heater was very low powered and the heat was close to the corrector instead of trying to heat the tube etc.and wasting power.

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"fitted in the corrector plate flange, this together with a dew sheild worked exceptionally well"


 


That's a very good tip - thanks Phil I'll attempt to arrange mine that way - they're dead awkward with the dew strip around the flange and under the shield. Nice one :)


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Thanks everyone.


 


Still a few models to consider out there, though I do fancy looking into a tailor made Maplins job for the Corrector plate as Phil has described.


 


Cheers.


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Guest Tweedledum

Hi Pete,


 


Had a kendrick on the lx, onto a home made dual controller. Looks like you are going to need a wiring loom, let me know if you need soldering and pcb's making up.


 


Cheers


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Check me on this but I think Astrozap (or AN other make) do dew shields with built in dew bands that plug straight into a 12v battery obviating the need for a controller. Of course there's only one setting for this type - but it might be useful. :)


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I think so Daz - if it is then they've modified them for dew controller power sources. The one's I saw a while back used to plug straight into a 12v powerpack. :)


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Thanks Kim and Darren,


That heated shield does look good and for the 10" SNT it is about the same price £69 as the BC&F metal one that I got with the scope. The BC&F one is not really long enough, in fact it is lightly shorter than it is wide so not such a good design.


 


Thanks Phil,


I will have a study at your DIY heater. That looks a really neat job.


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Hi


 


Just note i have a nearly new kendrick 2 channel 4 port dew controller going cheap as I do not need


it any more as i use i hitec hub


 


Sheila


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