Star Trail Help

vinay_sinha

Active Member
I think you have got an excellent set of images for a first try.What I would suggest is to do two things:
1) Make sure the Polaris is a part of the frame so that you get the entire circular trails in your image. The starting part of this thread has some notes about finding the Polaris.
2) Most important part is to get something in the foreground. The star trails should be a part of the image but you need to have a subject which grabs your attention. See if you can compose the images accordingly.
Thanks for the advice Chetan. I shall try again and try to locate the polaris.


The pic. is very good for the first try. As Chetan said you need better composition, you have nailed the exposure. Try some more.
Henry
Thanks Henry. Ill sure try out some more today. One question - theres hardly any difference in the length of the trail between the 2 pics though the 1st one is stacked out of 10 shots while the 2nd one has been stacked out of 100. Also why is there the gaps between the trail. Is it that the interval between the 2 shots needs to be reduced.


The quality is nice but the composition, not so much. Tanveer once suggested an easy trick to locate the Pole Star. On the big dipper (the one that looks like the spoon), the pole star is the brightest star right above the last two stars on the spoon part.
Finding the Pole Star
Yeah Zack I know. The problem is that I could not find anything else to focus on in my garden while at the same time trying to cut out the street lights. Ill try some more today, try to locate the polaris and put it up for critique. Thanks.
 

zack2137

Leh'd and how!
Vinay, where did you click these?

Also, the trails in the 2nd one are visibly longer than the first one. Ideally, the gap is caused by the time taken by the camera to add the black frame. But then I can't answer why the following picture also has gaps even when it was shot in a single exposure with long range NR off :confused:

 

hensil

Guru
Thanks Henry. Ill sure try out some more today. One question - theres hardly any difference in the length of the trail between the 2 pics though the 1st one is stacked out of 10 shots while the 2nd one has been stacked out of 100. Also why is there the gaps between the trail. Is it that the interval between the 2 shots needs to be reduced.


Thanks.
Yes, reducing the interval and also reducing the shutter speed will shorten the gaps in the trail.
However, one with 4 secs and 10 frames and the other 2 sec. with 100 frames and even then shorter trail, this has confused me. Please check the exif.
Henry
 

Chetan Kulkarni

Super User
If we look at the overall exposure it is 40 seconds for the first image and 200 seconds for the second one. Assuming the gap between each frame was almost negligible you are bound to capture a longer trail in the longer exposure. Simply because the star will move a longer distance in the sky :)
 

vinay_sinha

Active Member
Thanks all. HOwever Im still a bit confused. Henry Ill check the exif later sometime and will clarify.
Chetan, what effect does the number of images used while stacking have on the output as in the 1st image Ive stacked only 10 shots while in the 2nd one Ive used 100 but theres not much of a difference in the quality or exposure of the trails.
 

Chetan Kulkarni

Super User
Chetan, what effect does the number of images used while stacking have on the output as in the 1st image Ive stacked only 10 shots while in the 2nd one Ive used 100 but theres not much of a difference in the quality or exposure of the trails.
While capturing a star trail you are essentially trying to capture the light emitted by a star. While your camera is stable, the stars move around in the sky in a circle around the Polaris. Hence the longer your total exposure the longer is the length of the trail.

Where Henry's query comes from is that if there is a gap between two images, that is you take a 4 second exposure and then wait for 2 seconds and then take the next, then you will have gaps in the light being captured and therefore the trails will be dotted. In case there is no gap then you will get a single line of light (i.e. star trail) till the time you capture it.

Unfortunately I don't have a good example to explain it with otherwise things would have been simpler to understand
 

rajput.ankush

Active Member
Here's my first ever attempt at star trails.. shot in Chitkul..
Stacked 53 images with 30 sec exposure each. Means around 25 minutes of total exposure.
As it was my first try, didn't knew what the output will be... got a lot more trails than expected :p


Is it a good image ? or trails are too much.. should there be a less trails ?
 
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