Designing and Building a Low Cost Dew Heater System

www.theastroim... Presented by Steven Sagerian
-Brief explanation of what causes dew, and ways of combating it.
-Design parameters for a dew heater system
-Building a dew heater controller
-Building many dew heater elements and doing it safely
-Connectors, connectors and cigarette lighter plugs
-Power requirements for your new system, subtitled "purchasing a new deep cycle battery"
-"Best ever!", cheap stuff from china and where to get it.
Link to Spreadsheet...drive.google.c...

[@seabeepirate]

Can't wait to do this myself! Another argument against the ladder arrangement is that in it's failure mode it will heat your OTA unevenly because the resisters are in parallel instead of in series. A series resistor is like a chain with the chain breaking if any link is cut. Parallel is like a chain net, if you cut one link there are others still working. Normally redundancy is helpful in electrical circuits but in this case I think not working at all is better than working unevenly.

[@keithkorthals6183]

Easy to make. I did it. I just applied the nichrome wire to duct tape make sure not to short out. Good quality duct tape.

[@Jackcr33]

Very good information and presentation , I just made a resistor heater for my telrad which I found on the web it is made of a 2 watt 100oHM resistor , I am in Ontario Canada and we get lots of dewy nights

[@thomasfretz9684]

Can’t get the spreadsheet it needs a google account or something I don’t have.

[@andrepotgieter3722]

Excellent presentation , build my own complete 4 port system along similar lines for a fraction of the cost of the commercial units.

[@clarencemumphrey]

Where can I get my hands on that spreadsheet? Google gives me an error.

[@TheNakism]

Is the MSPF you used 0.25/inch or 0.25/foot? The calcs in your exampes use per inch, but the table on the next slide says per foot.

[@flyvezina]

Nice video and seems easy to make. Does anybody have a recommended parts list? I live in an area where the light pollution is low and with COVID-19 and limit telescope and electronics stores nearby, forcing me to buy online. I like to order everything, so they arrive nearly at the same time. I ordered the 12V DC PWM Manual Knob Dimmer Switches for LED from China and it will take a couple months to receive them. I like to have the parts list, but what I really like to know, what is the size of the housing? Again very informative and eager to build it.

[@TheElz8]

the MSPF is in inches (Watts/inch) , with that you calculate the total power (P) needed to defeat dew. Then you use R = V^2/P to calculate the resistance (R) needed. Now, assuming most people dont have a digital multimeter to actually measure the nichrome wire resistance, we use the charts(which show how much resistence per FOOT for a particular gauge of nichrome wire) to calculate the length of wire needed for R (most people have a tape measure or a rule) so.. {calc Watts needed} ---> {calc R for the desire Watts} ---> { calc length of wire based on R/FOOT} --->cut the wire, then build the heater based on the guidelines in the presentations.

[@zeroed4x]

A great presentation, thanks for sharing.

[@bretthaussmann2068]

This is fantastic thank you.

[@NikonJax]

Great presentation! I am working on the controller now :)

[@mjparker68]

Hi there. I'm gathering the bits and pieces to make this project. Great information. Where did you get the gray wire you used and what type is it?

[@talex001]

Hi - I tried the spread sheet for this and it does not seem quite right - maybe I missed something - I entered the scope circumference I wanted to make a heater band for (10" Meade SCT) which is 36" and it says 113.1 inches heater element, heating element length 1 feet? .5 up and back? I am using .28 resistance wire and want to several length's and even though I have gone through the video twice I must have missed how to use the spreadsheet... help would be appreciated.

[@robortiz4097]

I have a 2" dia. finder scope. When I plug this value in the spreadsheet, the length of the heating element calculates out as 17 ft. Is this correct? It seems like a lot of wire for such a small circumference.

[@joshmanske693]

this is awesome, any chance we can get a parts list?