CosmicOne SCT Cooler

[Rossco72]

Hi all,

Does anyone have any experience of or views on the CosmicOne SCT Cooler?

http://www.lymax.com/sct/

I am considering getting one of these to reduce the cool down time of my C11 as I store it indoors and have to travel to my set up sight and if this can reduce cool down time to 20 minutes then it would probably be worth it to me.

If you have one or have experienced one or have a suitable alternative then feel free to comment please.

Cheers

Stuart

[arad85]

Yup. I use one on my 9.25. Seems to do the trick nicely. Don't use it that much as I normally setup outside and just let the thing cool naturally.

Dweller25 on here used it for a while too and he swore by it.

[johninderby]

I used one when I had a C11 and found cooldown time was reduced by about 2/3. I used to allow about 40 minutes for a proper cooldown in the winter, but 20 to 30 minutes made the scope useable.

There's more to the Lymax design than is obvious at first glance as they have designed it to move the air in across the inside walls of the OTA and then out. Just blowing air into the OTA doesn't actually do very much.

I consider it an essential for an SCT.

John

[Rob]

Make one!... I nearly did with most equipment found in my local B&Q (other vendors available) + an 80mm PC fan picked up on ebay for £2. The plumng pipe section will sort you there sir!.

If you google there are some instructions on how to make one also.

Rob

[SteveL]

I had one on my NS8GPS. Once I had the tripod down and the NS8GPS on the top, I would put the cooler in the back and turn it on. By the time I had finished sorting out all the rest of the cables and power supplies and laptop (etc etc), the OTA was at ambient.

[Rob]

They are good.. and worth building / buying

[Psychobilly]

I'd be inclined to build as well...

You can get 2 part plastic fan guards that have washable filters in them.. the plenum chamber helps improve air flow...

Peter...

[Talitha]

Hi Stuart, on the occasions when you need to get going fast, the Cat Cooler's worth it's weight. Buy one or make one.. you won't regret it.

There have been extensive discussions about it over in the Cloudy Nights group. Some members questioned whether or not the fan would draw unwanted moisture into the OTA, but i never read any complaints of it having done so. I imagine if a slight amount of moisture was introduced, a dessicant packet would easily take care of it.

Other members questioned whether or not the fan would pull dust or pollen into the OTA, but common sense dictates that it not be used when you can see particles floating around. Maybe a finer filter could be used, but i'm not sure how or if it would affect the fan.

[michaelmorris]

I built one using a computer fan and some plumbing bits from my local plumb centre. The most expensive part was the power supply (around £12 if I recall). I think the whole thing cost me around £20. It probably isn't as effective as the Lymax, but it still greatly reduces cool down times and it didn't cost £100!

[brianb]

Some members questioned whether or not the fan would draw unwanted moisture into the OTA, but i never read any complaints of it having done so. I imagine if a slight amount of moisture was introduced, a dessicant packet would easily take care of it.

Hmmm .... the basic problem here is not only is it fairly humid (coastal) but the temperature is subject to wild fluctations when the wind is light (as it is during most clear nights), as the breeze swings from off the land to off the sea the temperature can rise by 5C in a few minutes. If the scope is properly cooled & ventilated then the internal optical surfaces will dew up .... the only cure that I can think of is having the vents contain active drying elements, either Peltier coolers to condense the moisture followed by re-heating of the dried air or to blow the air through dessicant packs.

It's all too much trouble really.

What I do is simply to have the tube sealed (with a silica gel sache inside the cap on the visual back when not in use, the prism diagonal maintains reasonable sealing when the scope is being used) and allow it to cool naturally. No problems with internal dewing though the outside can be & often is sodden. When the air temperature is reasonably stable, the scope eventually settles down & allows good images at high power; when the air temperature is unstable, the seeing is rotten anyway & cooling hardly matters.

Oh, IIRC silica gel needs to be heated to ~220C to regenerate it.....

[Rossco72]

Thanks for all of the input, I decided to purchase one as I really don't have the inclination or time to make one.

[dweller25]

Hello Rossco,

I had one for a couple of years for my C9.25.

I stored my scope indoors so cooldown time was an issue until I bought the Lymax. 30 to 40 mins would cool it down nicely.

Regards.

[Rossco72]

Thanks Dweller

I have the same problem, I live in a flat and have to store my scopes inside, once i drive to my dark skies site and get everything out the tubes still feel pretty warm. Can take some time to cool down.

Cheers

Stuart