Cool Down Issues?

[DeejayP999]

I often read about issues with cool down - particularly on reflectors and Maks.

Is this over stated or is it a real issue?

The reason I ask is that I'm a grab 'n go observer and I currently use an ED80 without problems, but I really fancy a bit more aperture (don't we always!) without increasing the overall size of the scope too much. Hence, I'm looking towards something like a Skymax 127 or similar but I'm concerned about cool down.

Am I worrying over nothing - or is it something I should be concerned about?

[Brett]

Cool down time is important, allow at least 30 mins before using the scope. This can be sped up by attaching a fan to the back.

Brett

[brianb]

Cool down time is important, allow at least 30 mins before using the scope.

... at high magnification.

You do no harm by using the scope immediately but the view at high magnification will be blurred until the warm air currents caused by the scope cooling settle down. At low power it makes no difference; I can use my CPC1100 immediately at x70 but it takes 2-3 hours before x300 is feasible, even on the rare occasion when the atmosphere is steady enough to permit it.

[Doc]

I agree with Brian, for high magnification any scope needs to be cooled. Sct and mak's are enclosed so seem to take longer to cool down. but saying that my 16" dob can take at least 90 minutes to really cool.

[russ]

This is also heavily dependent on where you store the scope and the time of year. For instance, if you keep the scope indoors and it's a cold winters day, the cool down time for a 5" Mak is going to be pretty scary. And as a Mak is used mainly for medium to high power lunar or planetary work, that won't be a good situation for a grab'n'go setup.

But if kept in a garage or shed where the temp difference is minimal, cool down won't be a big issue.

[Stu]

Just to add to this, my mak takes 2 to 3 hours coming from inside to a cold temperature outside. I run the inbuilt fans and also an eyepiece fan to get it down to temperature. If the temperature falls rapidly through the night then you need to keep them on as the otherwise the scope won't necessarily keep pace with it. You can use the scope but won;t get the best out of it

[Macavity]

I never found the cool-down time of my MAK127 restrictive. So I guess it was largely compatible with my general setup (and "screw around"?) time. <G> I do however see clear (almost textbook example!) "tube currents" in a MAK150 for a... fair old time. Again not too awful, but I have now moved to a secure (temporary for optics) outside store for the latter.