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Old 10-11-2011, 08:49 PM
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barx1963 (Malcolm)
Bright the hawk's flight

barx1963 is offline
Join Date: Nov 2008
Location: Waurn Ponds Vic
Posts: 3,798
Hi Paul, glad it was successful.
By heat haze I assume you are talking about shimmering images, especially when viewing bright objects such as Jupiter and the Moon? If so it is more likely to be poor seeing rather than heat haze as such. Poor seeing is not specifically related to temperature as it can occur regardless of the temperature on the ground.
Essentially it is instability in the atmosphere and is what causes stars to twinkle. It is present on most nights and can vary, there are very few nights where is is not there and not many more where it is minimal. The good news is that for visual purposes, DSO observing is less affected than planetary or lunar.
The key to beating poor seeing is patience. Keep watching and you will get little windows of clarity that will take your breath away.
Another cause may be tube currents, or warm air moving in the scope itself. This occurs if the scope has been indoors, the mirror is quite warm and causes them in the tube once it is taken outside. Thses usually settle down after about 30 minutes outside. I always take my 12' out 30 minutes to an hour before I plan to start observing to help the mirror cool down.

Hope this helps.

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