Beginners Problem With Star Tracer

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diskgolf3
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Joined: Thu Nov 29, 2012 12:35 pm

Beginners Problem With Star Tracer

Post by diskgolf3 » Thu Nov 29, 2012 1:14 pm

I am new to star trail photography but I am a professional Grapic Designer and a very experienced Photoshop and other design program user. I realize that Star Tracer is a very powerful and useful program for filling gaps and extending star trails. I can usually pick up on how most programs work by reading the help file and if needed I read through any related fourms, both of which I have done here. After all this I am still running into issues that I guess I just don't quite get. I think I understand the concept of the tools, input fileds and so forth but a couple of basic questions are baffling me:
How do you trace a curved star trail line? The star lines have to be straight right? Is there a way to edit a line after it has been drawn? It took me a while to figure out that to delete a line you have to hold control and and drag around it.
I am try to work on a file with a star circle(see attached). I have tried long lines that skip from end to end that kind of look like a bow and arrow if that makes sense. I've tried short lines that pretty much stay in the star trail but nothing seems to work. I tried to optimize bothe attempts but the updated numbers are very strange like FOV 546 or1.46. I outputed both attempts and they seem to just shift the star trails to the right and left.
I hope I have provided enough iformation to explain my problem with out over doing it and putting you to sleep.
Any help would be appreciated!

maxlyons
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Joined: Fri Jun 20, 2003 8:55 pm
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Re: Beginners Problem With Star Tracer

Post by maxlyons » Thu Nov 29, 2012 2:24 pm

diskgolf3 wrote:How do you trace a curved star trail line? The star lines have to be straight right? Is there a way to edit a line after it has been drawn? It took me a while to figure out that to delete a line you have to hold control and and drag around it.
The "star lines" really just have to connect two points in the trail. When optimizing, Star Tracer just takes the start and end point of the line, so if the center of the line doesn't lie on top of the trail, that is fine. Lines can't be edited, but as you have described they can be deleted, and then added again.
I am try to work on a file with a star circle(see attached). I have tried long lines that skip from end to end that kind of look like a bow and arrow if that makes sense.
That should be fine. I don't see any attachment, however.
I've tried short lines that pretty much stay in the star trail but nothing seems to work.
Without seeing the project file (and image), it is hard to tell, but my first guess is that perhaps one (or more) of the star trails is mispositioned (e.g. connecting the start of one trail with the end of another). If that isn't the case, it might just be that the optimizer is producing a bad value for FOV. If you know the FOV of your lens, then you don't need to optimize it. Can you post your project file and image?

Thanks,

Max

diskgolf3
Posts: 2
Joined: Thu Nov 29, 2012 12:35 pm

Re: Beginners Problem With Star Tracer

Post by diskgolf3 » Thu Nov 29, 2012 10:48 pm

Max,
Thank you very much for your reply!
I've read your post very carefully and I reworked the file as best I can. I made sure that connecting points of different lines were not connected. The FOV is 73.7 because I used a 5D Mark II so the Focal length multiplier is one and a 24mm lens. I pretty much left all the rest of the settings at default except this time I set the time to 300 Seconds to get a better read on the rotation. The layered PSD file shows the star trails rotated on a spot that's way off. I tried messing with all the settings with no success. I will try again to attach the screenshot and the output file. If you want me to email you the project file and image file I can. I also have a jpg file of one of the stacked files with the EXIF intact if it will help.
Thanks again for your help!
screenshot.jpg
output.jpg
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maxlyons
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Re: Beginners Problem With Star Tracer

Post by maxlyons » Fri Nov 30, 2012 1:00 am

diskgolf3 wrote:If you want me to email you the project file and image file I can. I also have a jpg file of one of the stacked files with the EXIF intact if it will help.
That image and project file would be helpful, but before we do that here are two things I noticed from the screenshots:

1. It looks like the pitch and roll values in the first screenshot have not been optimized. I presume that is just because the screenshot was taken before optimization, and not because you tried to generate a final image without optimization?

2. I see that the image size is listed as 857x1286. This suggests to me that the image was taken in portrait orientation (i.e. height larger than width). Star Tracer needs to know the horizontal FOV (i.e. the FOV measured from the left to right edge of the image). A FOV value of 74 would be correct if the image had been taken in landscape orientation, but a value of 53 is more reasonable for an image taken in portrait orientation. Can you try using this value, and see if it solves the problem?

Max

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