Best Practices

Flat frames are essential in astrophotography to correct optical issues like uneven illumination, vignetting, and dust particles on the optics. They are captured by photographing a uniformly lit source, such as a white screen or twilight sky. These reference images help remove imperfections during the processing workflow by dividing the original images by the flat frames, resulting in cleaner, more accurate final images. Flat frames are crucial calibration tools that enhance image quality, making astrophotography more visually appealing and accurate.

One of the fastest, cheapest, and easiest ways to capture flat frames is to simply use the sky. If you use N.I.N.A. (Nighttime Imaging ‘N” Astrophotography) to control your imaging rig, you can use the integrated processes to incorporate sky flats into your imaging sequence.

As expected, astrophotos are filled with stars. Hidden treasures often lie behind the starry brilliance. This is where the magic of StarNet in PixInsight is used to remove the stars that obscure the breathtaking details hiding in the background.

What if you could remove the stars? What would you be able to do?

The blurring effect within an image is often characterized by a mathematical function known as the Point Spread Function (PSF), which describes how a point source of light is spread out in the image. The point light sources are your stars, which should be circular.

When used with the PixInsight Deconvolution process, an accurate PSF model shows the blurring characteristics within the image, which deconvolution can correct. To be accurate, the PSF creation process should use a linear image (one that has not been stretched). When an image is stretched, the PSF characteristics are no longer accurate, resulting in a poor deconvolution result.

Many astrophotography workflows often recommend removing stars to simplify image processing. Without stars, you are able to focus your attention on the nebula and galaxies. However, the process of star removal can often remove some of the finer details within your image. This is why star removal is often completed early on in the astrophotography workflow.

But an interesting question often arises: Should I run deconvolution before or after I remove the stars?