In the case of captures taken over many hours with a star tracker, is it necessary to correct the orientation of the images before stacking so that they are all oriented in the same way?

In the case of captures taken over many hours with a star tracker, is it necessary to correct the orientation of the images before stacking so that they are all oriented in the same way?

In principle you don't have to flip any image (and even less if you stack in RAW). 

Nebulb always performs stacking with all images oriented in the same way. This is something that Nebulb manages internally based on the information of the images and their metadata (where the camera orientation information is).

Thus, the only thing you may have to do (when importing images into Nebulb) is to select the orientation of the base image (if it does not have the orientation you want).

In that case, before stacking, you simply have to rotate the base image to the orientation you want (with the rotate buttons on the top toolbar) and Nebulb applies that same orientation to all the images in the stack (without having to do anything else).

For example, this is the orientation that Nebulb shows me when loading a stack of images captured with a star tracker for more than 6 hours (time during which the camera has completely changed its orientation):



But since I wanted Orion to be vertical in this case, I simply applied a flip to the image (before stacking) and Nebulb already took this orientation into account for the rest of the images in the stack (regardless of the fact that there could be images with different orientations):



Thanks to which the final image was in the same orientation:






    • Related Articles

    • How many images are needed for stacking?

      This depends mainly on the noise level of your camera and the amount of light pollution you need to reduce. As a general rule: Higher noise → More images for stacking. More light pollution → More images for stacking. That said, I have found ...

    • No star reflections appear in the water when stacking star trails with Nebulb

      Cuando realizas un apilado de star trails en Nebulb tienes dos opciones para la representación de la parte del suelo: Sigma-clipping Maximum Well, if you select the sigma-clipping option for the ground, the stars will not appear reflected in the ...

    • Do all images need to have been captured with the same parameters for stacking?

      No, but yes. Let me explain. There is no problem in stacking images captured with different parameters in Nebulb, but for noise reduction these different images do not add, but subtract. That is, if you stack many images and some of them have ...

    • I get very white star trails in a star trails image

      To make the star trail images look as colorful as possible, I recommend 3 things: 1. Set appropriate capture parameters so that the stars are not too burned out and keep enough of their color. I usually use an ISO 800 (or even lower) and close the ...

    • Can the masks be modified after the stacking is finished?

      Yes, Nebulb also allows you to modify any of the masks once the stacking has been done, for this purpose: 1. Modify the mask as desired. 2. Once you have made the necessary modifications press the refresh masks button (so that Nebulb uses the new ...