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Post by Deleted on Feb 12, 2014 23:14:41 GMT
Whats peoples thoughts on this?
I know all scopes will have a different cool down time based on the type of scope and temperature condition changes i.e. moving from a hot house out into freezing weather.
Me personally i have never really cared and just get everything setup and running as fast as possible.
How would you even tell if the scope is cooled enough or whatever? How does it effect the image?
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Post by Deleted on Feb 12, 2014 23:22:01 GMT
I never use anything but fracs, so i can't offer any opinion based on experience, however scope cool down is supposedly important to let the mirrors adjust to the ambient temp. The scope tube will cool quickly, its the glass that takes time.
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Post by Deleted on Feb 12, 2014 23:28:52 GMT
Well with mine the general rule is 10 Minutes per Inch (6 Inch reflector) so an Hour or so. I do now do it to get the best on a viewing night. Just set it up where its going to North and leave it.
The effects of a warm scope are similar to bad seeing so I'm lead to believe as in focus and wobble problems.
Yours is longer as it is sealed, but I have just taken it out at short notice and had great views?
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Post by Deleted on Feb 13, 2014 14:06:48 GMT
Chris, your OTA cool down time can be optimized with an air pump. Pull your diagonal and introduce a light flow of air. There was one available for SCT's over here for a time, may still be. But, a DIY rig could easily lashed together. Precautions would be to filter the inflow and keep from touching the tube/optics.
Bob
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Post by Dragon Man on Feb 13, 2014 15:27:36 GMT
Chris, with Video Astronomy it isn't too big a deal. For astrophotography it is critical. For visual it can be a bit of a nuisance as the view of the Moon and Planets look like they are boiling, and DSO's look smudgy. Even with Video on the Moon and planets it looks messy and boiling, but it sort of adds to the 'Live' experience Video on DSO's it isn't really much of a bother. It might look a little out of focus for a while but as the optics cool you can get focus sharper. Depending on the temperature difference too. If inside is only within a few degrees of outside, you'll be right to go pretty much straight away. If the difference is about 10- 15 degrees you might want to let the scope sit for about 20 minutes. Any larger difference and you will have a long wait. With my scope (usually the ED80) I pop it on the mount early and let it equalise while I am laying out my cables, starting the computer, waiting for total dark, etc. As soon as I am ready I use it. I don't check for any temperature equalisation. It always seems fine and focusses well. Compared to Astrophotographers, Video allows us to be quite slack in a precise set up. No guiding, Alt-az works fine, thin clouds are OK, bumping the mount doesn't matter, excess light doesn't matter, etc etc. Cool down time doesn't matter too much either
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Post by Deleted on Feb 13, 2014 16:57:41 GMT
Cheers for your input on this guys! I will try and make an effort to give it a bit longer but its defo not something that would delay my session for an hour or whatever after setting up. I was reading reviews on my scope and some guy sold his just cause it was taking too long to cool down lol.
Question about cooling...does the same logic apply to the camera its self? Cause for me the camera is the very last thing i take outside when setting up. Should i let that cool from the start along with the scope?
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Post by Dragon Man on Feb 14, 2014 12:18:16 GMT
Chris, this might sound stupid, but I know people that do it.
If you want to cool your camera, stick it inside two plastic bags (one inside the other as a double barrier) and keep it in the fridge. It won't hurt it, and it will be already cold when you set up. I also know one person that keeps his Canon 5d DSLR camera and Takahashi Richfield scope in the fridge. He is a very serious astrophotographer.
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Post by Deleted on Feb 14, 2014 13:21:27 GMT
LOL Ken! Seriously? Im sorry but i dont care if it would give me the ability to see aliens... i still wouldn't be putting my MCX in the freezer! I think astrophotographers are just too anal! A little rough and ready never hurt anyone
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Post by Dragon Man on Feb 16, 2014 13:00:46 GMT
Not the Freezer Chris, just the fridge
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Post by Deleted on Feb 25, 2014 18:53:02 GMT
For visual I wait about 30min with my 6"dob, and about 20 for my XLT102. From Spring til end of fall I keep my dob on the patio and the 102 in the shed. This keeps the cool down time shorter. Winter it's much longer. I set up and then go in for a coffee and by then it's cooled to ambient temp.
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