Dew Heater Tape - AstroZap or Dew-Not?

[russellhq]

Anyone have experience of both of these and would suggest one over the other?

I'm leaning towards the Dew-Not heater tape as it sounds like it doesn't need a dew controller, so you can just turn it on and forget about it. Thus one less thing to worry about.

[PorkyB]

I think any tapes can be run without a controller, but in my experience you don't often need full power so you will be wasting battery.  Also, making up adaptors to plug them into your power supply might cost half as much as a controller anyway.

I use the bargain priced tapes from W&W Astro on Ebay with a controller from Modern Astronomy.  Very happy with both.

[neil phillips]

 Hi Guys

All I want to do is remove dew from a SW 300p Secondary The 2" tape might  work if I can somehow have it touching the back. I don't want continuous dew control. All I want to do is switch it on when the secondary dews over. Then switch off. leave a few mins to stabilize before starting planetary imaging again. I would have thought being a 12 volt it could be wired either into a 12 volt plug ( not sure if regulated would be needed ) or a 12 volt battery pack. I might have a plug or a battery pack here. Total cost 13 quid for dew removal. Wondering what others think about this idea ? of course the tape can not touch the front of the secondary. But I might be able to figure a way to attach the tape to the back of the secondary. Wonder how long it would take to clear a dewed up secondary, using this idea. Hair dryers are out of the question too noisy. And warm air dews the primary over. I know ive tried.

[russellhq]

I think any tapes can be run without a controller, but in my experience you don't often need full power so you will be wasting battery.  Also, making up adaptors to plug them into your power supply might cost half as much as a controller anyway.

I use the bargain priced tapes from W&W Astro on Ebay with a controller from Modern Astronomy.  Very happy with both.

Thanks, they look just like the Dew-Not bands but 2/3s the price!

[Tinker1947]

 Hi Guys

All I want to do is remove dew from a SW 300p Secondary The 2" tape might  work if I can somehow have it touching the back. I don't want continuous dew control. All I want to do is switch it on when the secondary dews over. Then switch off. leave a few mins to stabilize before starting planetary imaging again. I would have thought being a 12 volt it could be wired either into a 12 volt plug ( not sure if regulated would be needed ) or a 12 volt battery pack. I might have a plug or a battery pack here. Total cost 13 quid for dew removal. Wondering what others think about this idea ? of course the tape can not touch the front of the secondary. But I might be able to figure a way to attach the tape to the back of the secondary. Wonder how long it would take to clear a dewed up secondary, using this idea. Hair dryers are out of the question too noisy. And warm air dews the primary over. I know ive tried.

I think to make it work it needs to be on all the time, as its takes time to warm up and then maintain the tempreture, depending in how you would source the voltage, a long lead would allow for voltage control on a small heater this might only need 5-6 volts, from a battery the control unit would get damp ect unless sealed in a box......these controllers are very cheap on E-bay...

[russellhq]

Tinker, what type of dew heater tapes are you using? And do you know how much current they draw?

[Tinker1947]

The ST80 had a Revelation heater, use to run at 5 volts, kept the scope clear, i have a C11  and a 12" tape from FLO, it runs at 12 volts and while i have only used it a couple of time the glass on the end stays clear, with my 10" newt i used a dew shield this worked very well keeping the secondary clear.....

 

[neil phillips]

I think to make it work it needs to be on all the time, as its takes time to warm up and then maintain the tempreture, depending in how you would source the voltage, a long lead would allow for voltage control on a small heater this might only need 5-6 volts, from a battery the control unit would get damp ect unless sealed in a box......these controllers are very cheap on E-bay...

I wonder if the secondary was already dewed. How long it would take to clear once switched on. Surely it would still clear it. even if I had to wait a hour ? Even that would be better than whats happened to me recently. I had to abandon the rest of night because of this problem. A hour loss would have been more acceptable for sure.  Surely it would eventually clear the dew. once already built up ?

 Not sure I want continouse control. Heat even slight amounts are bad news for very high power planetary imaging, hence the desire to remove dew. not prevent it.

I could in theory start it up before the secondary had completely dewed over. I don't like the idea of even tiny amounts of continuous heat, at say 10 meters focal length. A dewshiled helps it doesn't prevent on my 12"