Yes, Professional Plastics is the place to get it. They'll charge you a reasonable price and ship it to you. Ask for: .028 thick X 48" X 96" general purpose...
Hi all, I was thinking of getting a Telrad Heater from Moonlight Telescopes. My fan keeps my mirrors clear, so I don't need to worry about that. Anyway,...
... Potentiometers aren't designed to handle much power. It might work in this case, but you couldn't run a full SCT dew heater through one. And you'll get a...
Anybody, How do you like your T-scope??? How do the optics compare to other big dobs. I'm specifically interested in the 14". Any comparisons to say...
... Hi Chuck, I don't own a T-scope, but I have several friends who do (both the 13 and 14 inch models), and I've seen and used them on a couple different...
I have a 14" TScope with the Peerless Optical Package (Obsidian Optics 1/20 wave primary). I'm delighted with it. The construction is first-rate. Motion is...
Why use a controller at all? Surely at 0.16A is about two watts. A 7AH lead acid battery would run this heater for about fourty hours (unless it's very cold...
Doug: You are right. The heater alone will be enough and might just use a little more energy that if you use the controller. In fact it might use less if the...
Sorry for the confusion below: 0.14 watt might not be enough. If you want 2 watts, you need a total resistance of 72 ohms. That is three resistors in series of...
Jean-Paul, you mention hooking the three resistors up but it is not clear as to where in the circuit you are talking about. Also you mentioned some screws on...
The resistors are just wired in series from the power supply (don't use the batteries from the telrad itself- those won't last very long). Using a 12V power...
take care on what you recommend! 1 W carbon resistors would get REALLY hot if they were run at 2/3W! I would go with more resistors in series and bring the...
I've modified my telrad according to a picture found on this site: http://www3.sympatico.ca/mark.kaye/equip.htm (about one-third the way down). It is simply a...
Completely agreed. In my setup, (225 ohms for 3 resistors in series), total power is 0.64 watt, or 0.21 watt for each resistor rated at 0.5 watt.. Jean-Paul...
Hello all, In about a week or so, I am going to start showing the building of my new 28" Starstructure Goto Dobs. Because of the overwhelming response to this...
Thanks all that responded. the information is greatly appreciated. In particular, than you Jean-Paul for bringing this up. This would make a nice club...
I agree with Gary. I would recommend no more than 1 watt total. A couple of years ago, I used three 47 ohm, 1/4 watt resistors in series, encapsulated in...
er... make that "... and feel in your hand how warm they get." :-) CS ... From: C. Starks To: bigdob@yahoogroups.com Sent: Friday, February 04, 2005 7:49 AM ...
Jean-Paul: Let me understand you clearly : You have a 2W (72 ohms) resistance for the telrad, but you think a 0.14 W (990 ohms = 3 resistances of 330 ohm)...
Since we are in dew heaters, I have problems of dew on my 5.1" (130 mm) secondary, 20 mm thick. Could anyone tell me how much power do I need to install to...
Raphael--- I'm using a 5.35" x 1" secondary with a 27" length of heat rope held on with rtv, no foam backing. The rope is 160 ohms @12v = .9 W. I've not had...
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... Astrosystems secondary dew heaters use 2 to 4W, depending on the size. They have 3 sizes of heaters for 2.4 to 3.5+" secondaries, so that's about 1W per...
Raphael: On my Obsession 18, with 3" (or is it 3"1/4) (short axis) secondary, a 160 ohm 0.9 watt wire heater is inserted in the back of the secondary. That...
According to John Vogt I'm now fixed on the amount of heat I'm going to put on my secondary : 0.8 or 0.9W => total resistance (in serie) = 160 ohm I'd like to...
In effect your putting two resistances together in series, the fan and the pot. The maximum disipation in the pot should occur when the resistance of both is ...
"pots" are also not designed to pass this amount of current! g. ... and the pot. ... of both is ... 120 ohm ... than half ... in the pot ... than the max ... ...
You would be better off simply inserting a series zener - short it to have full flow - leave it in place to have reduced flow....[a 3.3V 1W zener would do a...
