Best dew heaters?

[gregbradley]

I have never used a dew heater before. My experience with SCTs was when I first started in astrophotography and I moved on to other types of scopes fairly quickly.

My AP RHA may not really need dew heaters but I thought it would be good to have one available should I need it. I don't want any dew forming on the mirrors as I am sure it leaves a slight residue stain if it happens repeatedly.

Kendrick is one name I have heard of.

I would appreciate others knowledge of whats out there that is top notch.

Do dew heaters distort the optics appreciably or is it minimal and not really an issue for imaging?

Greg.

[Paul Haese]

Mate move to Clayton and find out how quickly you need a dew heater. :eyepop:

Where I am I use the dew heater terminal on a Mount Hub Pro at full belt on both my FSQ and my RC12. No distortions seen as yet.

Now for your RHA I am not sure, there might be some tube currents.

I use also a Dew Buster unit. It was cheaper than the Kendrick and has worked flawlessly for years. I don't know if those are still available.

[RickS]

I have a Dewbuster too. They look like they are still in business: http://www.dewbuster.com/

The Ceravolo has dew heaters and a controller built in so haven't needed the Dewbuster for a while, but it worked a treat on my FSQ-106ED. I like being able to use a temp sensor to dial in a controlled temperature delta.

Cheers,
Rick.

[gregbradley]

Sounds good. Thanks for the recommendation. The RHA only showed a bit of dew first thing in the morning and it did not show up in any images which finished at around 5am. I also did not use the scope fans. The 2nd night was windy so I took the dewshield off and this made it start to dew up a little much earlier. That was with the fans on. So it would be handy in that situation.

The thermal blankets help.




Thanks for the link. That looks good. I assume its compatible with Kendrick Premium heating strips.

[garymck]

I'll third the dewbuster - built like a tank. I've dropped mine on concrete without damage. I particularly like the ability to add temperature sensors so you can minimise heating by setting it to keep things just above the dew point.

cheers
Gary

[RickS]

The actual heater strips are all compatible. They are just simple resistive elements.

[gregbradley]

Thanks Gary. It does not seem to have any displays so it does that internally?



Makes sense. Thanks Rick.

[garymck]

[QUOTE=gregbradley;1172429]Thanks Gary. It does not seem to have any displays so it does that internally?

The controller has 2 sockets at the top into which 2 sensors (they cost a little extra) can be plugged. It then has 2 sockets on either side that can be controlled by the sensors. The rotary knob on the front is set by trial and error and sets the point where the heaters kick in. It's no great trial to do so accurately.

It also has another couple of sockets on either side that can power strips that are not controlled by the sensors.

Also has a couple of power outlets that can be used to power other accessories.

Incredibly well built and one of those rare items that is actually worth what you pay for it.

cheers
Gary

[Camelopardalis]

If you're not into rolling your own heater straps, I like the Dew-Not (http://www.dew-not.com) ones.

[gregbradley]

[QUOTE=garymck;1172485]

Thanks Gary. I'll order one.



Thanks for that link.

Greg.

[peter_4059]

I've got the original Kendrick Premier heater. It works well. You can dial in fixed temp, fixed delta above ambient and fixed delta above dew point.

[gregbradley]

Just reading the Dew-Not site there seems to be a rivalry between Dew Not and Kendrick. The complaint about Kendrick was excessive power consumption and a hot spot from a wire versus a film more evenly spread as well as price. Also a 2 foot longer cord on the Dew Not.

Power consumption may be an issue as I use a generator and 5 amps at 240V is 1200 Watts and that would make the generator rev a bit which I don't want (being at night and quiet etc). It would use more fuel. So half the power consumption sounds the way to go at 2amps or less and then with sensors so it only cuts in if the temp difference is 1 degree or so. That probably only occurs just before dawn or if its windy and I use it without the dewshield I could dial it in earlier.

Greg.

[peter_4059]

I wanted a controller I could adjust and monitor from the PC so the Kendrick Premier was the choice for me.

I suspect the power consumption will mainly depend on how many and how large the dew straps are - not the controller.

All of my dew straps are Kendrick Premier line (4 in total ranging from 2" to 10"). All work perfectly and I've had no issues.

[peter_4059]

Just set up and checked power use:
EQ6 parked + Kendrick Premier controller with 0% output = 0.47A
EQ6 parked + Kendrick Premier controller with 50% output on 9/10" strap and 50% output on 2" strap = 2.87A

[peter_4059]

Thought you might be interested in the Kendrick pc interface...

[Nortilus]

I have the Kendrick Digifire 7 with 2 straps on it...great unit, can set temps for 4 of the channels and the other 2 are just on flat out i think but since i never use them i cant quiet remember. The controllers body is stainless so it is very durable. power comes from 12v cigarette lighter plug type connector.