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Want to take star circles

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NightOwl
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Re: Want to take star circles

Unread postby NightOwl » Mon Sep 06, 2010 10:35 am

If you want the circle of the startrails centered, you need to point the camera at "celestial South" and not just South. Celestial south is in the sky and thats where the stars will revolve around. Take the southern cross's long end and extend it 4 times towards the bottom end of the cross. Then take a right angle line between the to pointer stars next to the Southern Cross and extend that till it intersects with your first line. Point your center focus point to this area in the sky and your star trail will be centered.

In the Northern hemisphere, just point at the North Star.

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NightOwl
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Re: Want to take star circles

Unread postby NightOwl » Mon Sep 06, 2010 10:37 am

To do a star trail without using stiching software, hook the Camera up to your laptop with the supplied USB cable. Then use the controll software that usually bundles with the camera (Canon it's EOS Utility). You can then do longer than the 30 second exposures.

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DuQues
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Re: Want to take star circles

Unread postby DuQues » Fri Sep 10, 2010 10:34 am

NightOwl wrote:In the Northern hemisphere, just point at the North Star.

Polaris is the name of a star much more commonly called the North Star. Polaris lies less than one degree from the celestial North Pole, an imaginary point directly over the Earth's own North Pole. Polaris is not particular bright, contrary to what many people may think, so finding it in the heavens is not a sure thing, even when facing north. However, it is possible to use a constellation close to Polaris, and one that you will easily recognize, to locate this beacon of the northern sky.

Find the Big Dipper in the northern sky. This is not a constellation unto itself but rather a portion of a much larger star grouping called Ursa Major, the Big Bear. Look for seven bright stars that seem to be of the same luminosity that form the pattern of a ladle. Three stars make up the Dipper's handle and four stars form the outline of the Dipper's bowl.

Locate the last two stars at the very end of the bowl of the Big Dipper. These are the two stars known as the "pointers," since you will utilize them to point the way to Polaris. Polaris is the very end of the handle of the "Little Dipper," which is officially called Ursa Minor, the Little Bear. However, the other six stars in the Little Dipper are quite faint, requiring a clear night for you to see them. Concentrate your efforts on Polaris for the moment.

Trace a straight line from the bottom pointer star upwards through the top one. Continue the line outwards and away from the two pointer stars for about three times the distance your outstretched fist seems to cover when the sky is in the background. This will take you to a star that has about the same brightness as most of those in the Big Dipper. This is Polaris, the North Star.

Notice how during the course of the evening Polaris does not seem to move, although the Big Dipper does. This is due to the rotation of the Earth. As your position changes in relation to the fixed stars in the heavens, the stars seem to move in the sky, except for Polaris, which is "anchored" at the point over the North Pole. The Big Dipper will move counter-clockwise around Polaris as the evening progresses. Venture outside at three-hour intervals and this will be quite apparent.

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Re: Want to take star circles

Unread postby pepperjuice » Fri Sep 10, 2010 5:01 pm

For long exposures SWITCH OFF IS/VR

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Re: Want to take star circles

Unread postby Wild@Heart » Thu Sep 23, 2010 8:31 am

Please can someone help me ... How do I set my 55 - 250 IS Canon lens to focus infinity .. There's not button on the lens like the 400mm ... I want to try my hand at star trails this weekend even though not ideal (full moon, clouds etc) .. but I figure I have a better chance than in the city :D
NO TO HOTEL DEVELOPMENT IN KRUGER

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DuQues
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Re: Want to take star circles

Unread postby DuQues » Thu Sep 23, 2010 1:32 pm

Ah! You have no distance scale on your lens...

So what you need to do is to focus on something far away, like a cloud or a tree on a distant hilltop or such. It doesn't have to be miles away, just far enough.
Now you can see which way the focusring will turn far, and not far at all in the other direction. Keep that in mind, clock- or anti clockwise and when the light is gone just turn it all the way.
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