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SW 180 MC and a cooling fan ?

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#1 panagiotis

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Posted 14 February 2013 - 06:13 AM

Hello,

I have the Skywatcher 180 MC pro and I have it permanantly mounted at my rooftop and I am covering it with a beach towel, for the heat and moisture, and a telegizmo 365 cover. I know that these kind of scopes needs a long cool down time. As I don't have it in my house and take it out for observing I suppose that I need less cool down time. Am I right ?
I was also thinking about active cooling. I don't know what type of, as I had seen different places for the fans. Most of the modificated SC have fans at the rear cell, one blowing and one pulling air, but the experts at MC, Intes Micro, have one fan at the side of the scope, but I don't know where exactly, respecting to the mirror and if it is blowing or pulling air, or one at the back. What is your opinion ?
Also what about ventilation at the front ?

thank you,
Panagiotis

#2 KerryR

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Posted 14 February 2013 - 10:40 AM

I've added active venting to my CPC11 and 8" LX90.

On the LX90, a single 60mm fan blows into the tube from the rear casting, air exits the rear casting passively on the opposite side of the casting.

On the CPC11 a single 80mm fan ,if memory serves (maybe 60), blows into the ota from the rear casting, exits passively through a hole on the top of the tube just above the secondary mirror.

Both setups are unfiltered to maximize airflow, but regular size window screen prevents insects and dogwood fuzzies from entering the tube.

Both setups work very well.

There are now commercially available fans that are specifically designed for the purpose and would probably be the easiest to install. Here's the link.

#3 DHurst

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Posted 14 February 2013 - 12:57 PM

wow, for the cost of those fans, I'd consider a fleabay purchase from china.

#4 KerryR

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Posted 14 February 2013 - 03:50 PM

What would you find from China that was specifically engineered for this purpose, and designed for easiest retro-fitting? It's fairly easy to add computer fans, but the commercial versions look they'd be easier to install, lower profile, and look nicer. I'd have used them if they'd been available when I did mine.

#5 EFT

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Posted 15 February 2013 - 12:35 PM

A scope covered up outside could be quite warm if not uncovered a good amount of time before viewing. Active cooling will reduce cool-down time as well as keep the scope thermally stable while viewing or imaging.

The MAKs and MAK/Newts that use a single fan, usually have vents elsewhere (like around the corrector) that take are of the in/out issue. That is not the situation for most scopes though, so an in/out system needs to be used. In reality, you can use very small fans to do the job. Mag Lev fans in the 25mm size work very well. They have very little vibration so that they can be used while viewing/imaging and require drilling relatively small holes that can be done with a hole saw. Standard 60mm computer fans generally vibrate and will require large holes to be cut which is much more difficult.

#6 ahlberto

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Posted 15 February 2013 - 12:58 PM

Hi.This MC from SW are builf like a tank and they are very hard to drill,cut...etc...its a nasty scope to mod. I would see how intes micro uses the fans to cool down their MC and have a start from there :p

#7 EFT

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Posted 15 February 2013 - 01:08 PM

Hi.This MC from SW are builf like a tank and they are very hard to drill,cut...etc...its a nasty scope to mod. I would see how intes micro uses the fans to cool down their MC and have a start from there :p


A bimetal hole saw (I use 1-3/8") on a drill press can do the job. With a pilot bit, and hand drill can be used, but it's more difficult. Do definitely want to go with as small a hole as possible though since it only gets more difficult the larger you go. The downside with a MAK is that you are going to have the remove the primary and then realign it. Side fans would be easier to install, but are harder to make to fit the curved surface and run the risk of introducing stray light.






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