Guest Dex55 Posted January 11, 2012 Report Share Posted January 11, 2012 Am I right in thinking that the rule of thumb for cooling down is 10 mins per 1" of aperture? I am sure I have read this somewhere. Quote Link to comment Share on other sites More sharing options...
Guest Kheldar Posted January 11, 2012 Report Share Posted January 11, 2012 I don't know a fixed rule. My 8"s go out at least an hour before I do, ideally 90mins. Time will also vary dependant on temperature difference between storage location and outside. Quote Link to comment Share on other sites More sharing options...
Daz Type-R Posted January 11, 2012 Report Share Posted January 11, 2012 I don't know a fixed rule. My 8"s go out at least an hour before I do, ideally 90mins. Time will also vary dependant on temperature difference between storage location and outside. Same here, 1.5 to 2 hrs for me. Quote Link to comment Share on other sites More sharing options...
+Doc Posted January 11, 2012 Report Share Posted January 11, 2012 Longer the better but 90 minutes sounds good Quote Link to comment Share on other sites More sharing options...
glider Posted January 11, 2012 Report Share Posted January 11, 2012 I think SCT's take longer because they are closed. My 200P I used to leave an hour and that's open at one end. Quote Link to comment Share on other sites More sharing options...
+Doc Posted January 11, 2012 Report Share Posted January 11, 2012 Of course the bigger the mirror the longer it takes. My 16" took a good two hours. Quote Link to comment Share on other sites More sharing options...
Guest Dex55 Posted January 11, 2012 Report Share Posted January 11, 2012 Okay thank you for your advice, so if I allow 2 hours I should be well okay then? Quote Link to comment Share on other sites More sharing options...
Brantuk Posted January 11, 2012 Report Share Posted January 11, 2012 You can still use it from the time it's all set up - it's just a matter of the views will gradually get better as it cools down. An hour or two soon goes by - just make sure you revisit earlier objects to see the difference Quote Link to comment Share on other sites More sharing options...
Craig Posted January 11, 2012 Report Share Posted January 11, 2012 I confess, here and now, that I never cool my scope down. I'm far too impatient, I spend a little time checking the finder scope is aligned and then I just ignore any imperfections whilst it is cooling. Normally, I use the time it's cooling to practice star hopping. Quote Link to comment Share on other sites More sharing options...
+RonC Posted February 4, 2012 Report Share Posted February 4, 2012 With my 200PDS out in it's little obsy, mine is up and running straight away!! Quote Link to comment Share on other sites More sharing options...
+Doc Posted February 4, 2012 Report Share Posted February 4, 2012 With my 200PDS out in it's little obsy, mine is up and running straight away!! Show off Quote Link to comment Share on other sites More sharing options...
+Rusty Strings Posted February 4, 2012 Report Share Posted February 4, 2012 Mines out for an hour while I plan the session Quote Link to comment Share on other sites More sharing options...
philjay Posted February 4, 2012 Report Share Posted February 4, 2012 The cool down period depends on alot of things, is it open or closed tube, how much meat there is in the optics, how much meat there is in the tube, ambient temperature, temperature of the scope at the start etc etc. Also what you want to look at with the scope comes into it as well if you want to catch fine detail on planets or the moon and you shift the scope from a centrally heated room to outside where its -8 then its going to take longer to get useable images than if you just want to look for faint fuzzies where seeing fine detail doesnt really matter. Youll find alot of these one liner rules around, the unfortunate thing is they get trimmed down so they can confuse. My old C11 SCT (closed tube) used to take about an hour and a half in reasonable ambient temperatures to be useful for planetary viewing so I used to do a bit of DSO observing first until it had aclimated. My 4" F15 refractor (closed tube) takes about 45 minutes in similar temperatures.I used to have a little 6" newtonian astrograph that would cool in record times due to thin glass and open tube. Hope that helps Phil Quote Link to comment Share on other sites More sharing options...
Guest NadeemShah Posted February 5, 2012 Report Share Posted February 5, 2012 Depends in what I'm using tell you the truth, for refractors of around 80mm, about half an hour outside, one hour before imaging, I tend it to move the OTA from a warm room to a cold room then it goes outside for the final cooling stage... For my old MN190 it used to be 60-90mins outside before any imaging... Open tube reflectors about 30mins... Nadeem. Quote Link to comment Share on other sites More sharing options...
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