Jump to content


Photo

Oh no, please not again another diy dew heater

  • Please log in to reply
8 replies to this topic

#1 StellarDriftwood

StellarDriftwood

    Lift Off

  • -----
  • Posts: 21
  • Joined: 15 Dec 2011
  • Loc: Germany

Posted 13 February 2012 - 10:56 AM

Hi,

this is my new approach to prevent dew on my 8" SCT, and it worked twice so far. Comments welcome!

direct dew heater

(I've posted this before somewhat hidden in the Equipment section)

Herbert

#2 Ed Holland

Ed Holland

    Vanguard

  • -----
  • Posts: 2220
  • Joined: 16 Jun 2010
  • Loc: San Jose, CA and Oxford, UK

Posted 13 February 2012 - 03:28 PM

Very neat - I like it! Presently, I am trying to address the dew problem with my C8, without spending a lot of money, or making setup of the scope too time consuming. Your project gives me a number of ideas. Thank you for sharing :)

Ed

#3 Pinbout

Pinbout

    Cosmos

  • *****
  • Posts: 7842
  • Joined: 22 Feb 2010
  • Loc: nj

Posted 13 February 2012 - 03:45 PM

I need this for my faceshield on my motorcycle helmet so it won't fog up in the cold. :grin:


I already have 12v on my helmet for my bluetooth headset.

#4 roscoe

roscoe

    curmudgeon

  • *****
  • Posts: 3404
  • Joined: 04 Feb 2009
  • Loc: NW Mass, inches from VT

Posted 13 February 2012 - 09:33 PM

Yeah, so now what am I gonna do with the hundred resistors I bought??????
It's a very good idea!!
Russ

#5 Pinbout

Pinbout

    Cosmos

  • *****
  • Posts: 7842
  • Joined: 22 Feb 2010
  • Loc: nj

Posted 13 February 2012 - 09:43 PM

so how long does the battery last?

#6 StellarDriftwood

StellarDriftwood

    Lift Off

  • -----
  • Posts: 21
  • Joined: 15 Dec 2011
  • Loc: Germany

Posted 14 February 2012 - 02:55 AM

@Russ: become creative - make costume jewelry :lol:

@Danny: my battery is 7 Ah, we'd use 50% of the capacity. In my case the heater draws 0.25 A. 3.5 Ah / 0.25 A = 14 hours.

My next thought is to take off the dovetail bar and place the cable tie base below it to make the setup look much nicer.

Herbert

#7 Olivier Biot

Olivier Biot

    Amused

  • *****
  • Posts: 24946
  • Joined: 25 Apr 2005
  • Loc: 51°N (Belgium)

Posted 18 February 2012 - 07:30 AM

Very nice!

Only worry I would have in this setup is the resistive wire breaking off after a while, at the height of the connector.

#8 FrankenCub

FrankenCub

    Vostok 1

  • -----
  • Posts: 112
  • Joined: 26 Aug 2011
  • Loc: Whitney Point, NY

Posted 13 September 2012 - 11:28 PM

This has been a great idea ! Better than cheap, it can be free. I took apart an old toaster to see how those flat wire elements would work with 12vdc. Turned out great, third night with my new to me C8 was dew free. That flat wire forms nicely around that retention ring. I added an inline micro switch to mine.
Thanks for the post, Herbert ;)

#9 StellarDriftwood

StellarDriftwood

    Lift Off

  • -----
  • Posts: 21
  • Joined: 15 Dec 2011
  • Loc: Germany

Posted 17 September 2012 - 04:22 AM

Glad to read someone rebuilt it and is happy, too :)
My OTA is fog-free ever since.

Herbert






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics