Small amounts of rotating air can ruin your comments.
This negative image of double star Zetta Bootis shows the effects of atmospheric viewing. Tube streams can distort the star images badly. Credit: Nordic optical telescope
One of the most important factors for amateur astronomers is seeingWhich is defined as the stability of the atmosphere on your observation site. You can tell how good (or bad) to see a reasonable bright (2 magnitude) star near Zenith. If it is wildly flicker, it is bad to see. But if the image is relatively stable, then it is good for you to see. And while watching overall can be good or great, you can still see its effects when you see through your telescope. Can these tube currents be?
How to tell
The erosion of view is a widely recognized problem due to tube currents (also called thermal). But how do you know what it is Yours crisis? Indicate your telescope on a quite bright star and use your focus to defoction your image. This will actually allow you to see if an air stream exists. If the image is appropriately stable, your problem is not tube currents.
If, however, you see a lot of spherical motion moving inside the image, you have severe tube currents. My late-watching friend, Jeff Medkef, once told me, “If your out-of-focus star image has ‘hair’ or ‘ring of fire’ around the outer edges, and these patterns change in a subtlety of 30 seconds to five minutes, then you have image-hiratory tube streams-no one appears in the air.”
Solution
This problem is easy to fix, but you should have the right piece of equipment. The solution is to use a small, low-flow fan to blow up hot air from the tube. Your goal is to bring your mirror to the same temperature as the outside air. Once you do this, recover the out-of-focus star image and you should see noticeable improvement.
