Never used any reflectors, just refractors. So how long is the cool down time with say an 8 inch reflector? And just how much difference is there in the image before cool down versus after cool down?
Cood down times?
Started by electro, 11/24/2005 06:03PM
Posted 11/24/2005 06:03PM
Opening Post
Posted 11/24/2005 06:30PM
#1
Hi Dennis,
You can install an internal fan or use an outside mounted fan to make cool down much quicker. Plus an internal fan tends to lessen tube currents and onther heat related issues.
You can install an internal fan or use an outside mounted fan to make cool down much quicker. Plus an internal fan tends to lessen tube currents and onther heat related issues.
[SIZE="Large"][/SIZE][COLOR="Blue"][/COLOR] Floyd Blue
Amateur Imager
Posted 11/24/2005 06:34PM
| Edited 11/24/2005 06:34PM
#2
Hi Dennis,
Like Jarno said it depends on the scope's construction. I have had great success with closed tube Newts by installing fans. One at the back of the mirror and one on the side of the tube approximately one inch above the primary mirror with corresponding vents drilled opposite the fan. With this system my 6" f8 cools down in thirty minutes or less. The difference before and after the fans were installed was profound.
Clear Skies,
Steve
Like Jarno said it depends on the scope's construction. I have had great success with closed tube Newts by installing fans. One at the back of the mirror and one on the side of the tube approximately one inch above the primary mirror with corresponding vents drilled opposite the fan. With this system my 6" f8 cools down in thirty minutes or less. The difference before and after the fans were installed was profound.
Clear Skies,
Steve
Posted 11/24/2005 09:47PM
| Edited 11/24/2005 09:49PM
#3
I have an 8" f/8 in a sonotube with a cooling fan installed. I have three reflectors and fans on all of them for cooling purposes. I also have indoor/outdoor thermometers on each, with the outside probe insulated against the back of the mirror so I can compare ambient tempertures against the actual temperature of the mirror back.
How long it takes to cool is highly dependent on your local cooling conditions after sunset. If I take my scope from indoor temp (20°C) and place it outside where the temperature is 3°C and falling, within two hours the mirror is within 2°C of the ambient air. After four hours of falling ambient air, the difference is still 1°C.
I notice improvements in my high power observing at 2°C of difference. At 1°C the high power potential if the seeing conditions are good is quite significant. If I leave the scope out all night with the fan running, I can get very fine views of Saturn early in the morning when the planet is high in the sky.
I do believe fans in my climate are highly necessary for serious planetary viewing with reflectors.
Gary Weber
How long it takes to cool is highly dependent on your local cooling conditions after sunset. If I take my scope from indoor temp (20°C) and place it outside where the temperature is 3°C and falling, within two hours the mirror is within 2°C of the ambient air. After four hours of falling ambient air, the difference is still 1°C.
I notice improvements in my high power observing at 2°C of difference. At 1°C the high power potential if the seeing conditions are good is quite significant. If I leave the scope out all night with the fan running, I can get very fine views of Saturn early in the morning when the planet is high in the sky.
I do believe fans in my climate are highly necessary for serious planetary viewing with reflectors.
Gary Weber
Funding Member
