SCT, cool or insulate the tube

[billhinge]

Just reading on another site, some people swear by wrapping their SCT in Reflectix, others leave outside to cool.

Whats the best, both ways seem to have merit but I guess the warm option reduces dew on the corrector?

Anyone tried both options?

[johninderby]

I used one of these when I had a C11 which reduced cool down time tremendously. and stabilised the temp inside the scope.

https://www.rothervalleyoptics.co.uk/lymax-cosmicone-sct-cooler-r3-catadioptric-telescope-ventilator.html

Edited August 17, 2020 by johninderby

[billhinge]

Lol, there is actually a commercial product, I was thinking of making something similar out of a small pc fan, thanks for the link (or sticking a vacuum cleaner hose in 😀 )

[johninderby]

The SCT Cooler is more sophistcated than it looks. the end has angled jets of filtered air that circulate the air round the inside and exhausts it in a way that all the air inside is exchanged for cool outside air. 

Edited August 17, 2020 by johninderby

[dweller25]

I have wrapped my Intes Mak with two layers of reflectix and the benefits are worthwhile.

No need to wait for cool down and the corrector takes much longer to dew up.

A cheap, reversible and easy upgrade 👍

The standard cool down method I used to do caused the corrector to dew up much quicker.

Edited August 18, 2020 by dweller25

[Nigella Bryant]

I'd not heard of using Reflectix around the scope to help with dew/cool down. I've two fan's on the back of the 11inch XLT with a heated light shield and a large fan on the 12inch newt f4. Both seem to cope with dew and mirror/corrector plate fog. 

[pete_l]

The professional observatories keep the interior of the dome at night time temperatures all day long.

I am thinking of a "scope fridge" product. To be released in late March / early April

 

[Nigella Bryant]

5 minutes ago, pete_l said:

The professional observatories keep the interior of the dome at night time temperatures all day long.

I am thinking of a "scope fridge" product. To be released in late March / early April

 

And dome fridge, lol.

[billhinge]

So there seem  to be two methods, keep it steady by wrapping and get it to ambient temp asap

Most people seem to go for the cooling approach but some have tried the Reflectix approach, how long did the  benefit last and do you do your wrapping indoors?

How do you get the wrapping under the dovetail so that all the surface is covered?

[billhinge]

Been  reading   up on  this. There  does  seem to be some  evidence that  insulating works. Most people seem to use reflectex  but reading  up on  that it doesn't seem that good when wrapped

I may try a high tech solution after the next credit card bill. You can buy aerogel blankets for < £100, may give that a go

https://www.phstore.co.uk/aerogel-spacetherm-blanket

 

[dweller25]

You may want to try Reflectix first - it’s only £15

[billhinge]

but I may waste £15 😆

[dunc]

I use silvered radiator reflector stuff on my 8" Meade. Steadies the image well and plenty on the roll for a fiver. 

[nfotis]

On 22/08/2020 at 17:23, billhinge said:

Been  reading   up on  this. There  does  seem to be some  evidence that  insulating works. Most people seem to use reflectex  but reading  up on  that it doesn't seem that good when wrapped

I may try a high tech solution after the next credit card bill. You can buy aerogel blankets for < £100, may give that a go

https://www.phstore.co.uk/aerogel-spacetherm-blanket

 

 

From what I have read, my understanding is that the quick temperature changes result in air turbulence inside the tube.

Insulation makes the temperature changes much more gradual, leading to reduced turbulence while the scope reaches ambient temperature (either going up or down).

 

N.F.

 

[Ken82]

Or just cut up a camping mat like me 😀

 

[billhinge]

What I haven't heard is, does  the benefit of insulation last all night or does it degrade?

[procky1845]

How have people found is the best way to attach the reflectix to the scope?

I have a Skymax 127 that I'm considering this for. 

Also do you cover the end with the visual back as well or just around the tube?

[billhinge]

I have seen  pics with both, I don't think there is a manual  for this so it  would depend  on heat loss  through the back.  To be  sure  I would do the back as well but   I'll defer to  someone who has tried both ways though

[procky1845]

Just as an update, I went ahead and wrapped my Skymax 127 and managed to squeeze in a short observing session the night before last to try it.

I made a wrapping thats all one piece of insulation and has holes for the dovetail and finder shoe bracket and is held in place by velcro (so its easily removable if needed). Its effectively double wrapped around the tube with a single piece that hinges over the back (again held in place by velcro).

To test it I took the scope straight outdoors and set it up which took about 15 minutes and then started observing immediately. Didn't notice any particular seeing issues introduced by bringing the scope straight out of the house as I would have seen previously, and the seeing held consistently at the same level for the full hour I was out. Tested initially on a couple of bright stars, and then went on to look at some DSO's, mainly Planetary Nebulae and Open Clusters as there was quite a bit of thin cloud about.

The real test will be when I take it out to do some planetary observing but that wasn't an option the other night, it was more of a chance clearing amongst the endless clouds we're seeing in the UK at the moment so just went from the back garden.

Keen to see how it performs when I get the chance though!

(I'm not a fan of the imitation space telescope look though, if it hadn't been so promising after the first test it would probably already be in the bin  )

Lee