What do you guys use for dew control?

[mandaragit]

Thanks for the description guys, I guess ill learn this soon as I have a few serious obs under my belt. . .

So if I think dew is about to form, I just activate the heatpack and place it on the scope? Where do you put it by the way, on the dew shield or behind the dew shield (for refractors)?

[acc]

It will be too late to put on the heat pack after dew forms; put it on as soon as you start your over-night session. You can tape it behind the extended dew shield.

[mandaragit]

How about the temp of the heat pack, wouldn't it be too hot for small refractors? I mean won't it affect the turbulence in the inside of the OTA?

[kaomoo]

man.. i had the first hand experience with dew last night. U won't believe how fast they came. As I was doing star collimation, I didn't have my dew shield on. Within half an hour, my corrector fogged up. Even my Telrad fogged up too!

need to learn how to do this properly.

[kochu]

HEATER CALCULATIONS FOR LX -90
(1)Volt (2)Resistance of heater wire (3)CurrentI=V/r (4)Heater power in watts W=I^2R (5)Battery endurance in hours (7 Ah Battery) (6)Battery endurance in hours (12 Ah Battery) (7)Battery endurance in hours (17.5 Ah Battery) Remarks

1 2 3 4 5 6 7

12 10 1.2 14.4 5.8 10.0 14.6
12 15 0.8 9.6 8.8 15.0 21.9
12 20 0.6 7.2 11.7 20.0 29.2 Temp-41 Deg Cel
12 25 0.48 5.76 14.6 25.0 36.5
12 30 0.4 4.8 17.5 30.0 43.8
6 8 0.75 4.5 9.3 16.0 23.3

I had made many Dew heaters for my scopes earlier using Ni-Chrome wire purchased from SimLim Tower. The typical calculations for various types of batteries are as shown above.
But I still prefer 1 $ heat pads for refractors. The heaters are needed only when I bring out large dia SCT. Then you need many heat pads .

Kochu/19-10-11

[kochu]

Vow, The excel sheet looks awful.

Kochu

[kaomoo]

[quote="kochu"
But I still prefer 1 $ heat pads for refractors. The heaters are needed only when I bring out large dia SCT. Then you need many heat pads .

Kochu/19-10-11[/quote]

just found the $1 heat pads. Will try them out. Any suggestion where I stick them? Also how about Telrad?

[mandaragit]

do give some feedback kaomoo after using the heat pads, Im eager to try them myself, still trying to find where I can find it here in the Philippines

[kaomoo]

do give some feedback kaomoo after using the heat pads, Im eager to try them myself, still trying to find where I can find it here in the Philippines

I bought this one.


contains iron powder, water, activated carbon, vermicuute, salt, super absorbent polymer, Purge®, Natural mineral powder

[shirox]

5th floor of orchard 313 sells them at winter time.
there are small packs and large packs. Works a wonder and last whole night. A must for imaging in the open.
They are also available at daiso, a different version at $2 each.
Avoid using those heatpacks that is for muscle relief as it might contain extra chemicals or ailments. Best to read before u paste or strap it on. I use rubber bands for tailor that is 1 inch in width to hold the pads. Usually use 2 big ones for my refractor, 1 small for my guide scope and 1 small for my finder.