Op donderdag 28 december 2017 14:44:21 CET schreef Carlos E. R.:
On 28/12/17 05:25 AM, Carlos E. R. wrote:
Hi,
I have a bunch of sky photos with stars and some shooting stars (of 639 photos taken, 13 contain shooting stars, Geminids). I have seen photographs compossed of automatically joining several such photos so that you see one photo with a dozen(s) shooting stars.
How can I do that, in Linux?
(If not in Linux, then Windows)
The application I understand superposes several photos matching the stars one on top of the other (as dots) and the landscape, and then the shooting stars are seen as several lines.
Hopefully each image has a lot of the landscape in common so they can be aligned. I didn't move the camera for the entire session, using a tripod. It is
On 2017-12-28 13:51, Anton Aylward wrote: the sky which moves, ie, the Earth which rotates.
The normal tools to do this kind of overlay are for HDR. It assumes you are overlaying a +1 and - over/under exposure to ewnhance the image. I won't go into the why of HDR. But it does overlay the images and combine them as you point out.
All photos are dark. Night stars, no moon. Long exposures, open diaphragm, very high ISO.
- there is a HDR plugin for GIMP - there is hugin_hdrmerge - Merge overlapping images
which has a LOT of parameters you can tweak!
Another gimp plugin?
- there is Luminance HDR
Luminance HDR is an open source graphical user interface application that aims to provide a workflow for HDR imaging.
I've tried this and its very good
I'll have a look.
- there is openexr, which I haven't tried - these is pfstools
And of course there is the powerful manipulation command line tool ImageMagick, which can do pretty much anything you want, and which I'd look at first in your case. it has some GUI front ends/wrappers from 3rd parties.
- there are options in other photoprocesing tools such as Darktable
Notice that this tool has to examine the photos and shift them around so that they do overlap. The camera is on tripod, but the stars shift. I don't know if the correct thing is to match the stars or the very dark landscape.
A bit off-topic: why not create an animation of it ? Numerous apps available that can generate an mp4, gif ... -- Gertjan Lettink, a.k.a. Knurpht openSUSE Board Member openSUSE Forums Team -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org