Coping images

[Nzlowie]

Hi all
Can someone please tell me if taking 10 exposures then coping them is the same as taking 20 images to stack in DSS.?

If not why?

Just seams an easy way to get multiple images, just take 20 images then copy them, then copy them equals 80 to stack. Will it work.......

Cheers Dave

[pluto (Hugh)]

The point of stacking images is to improve the signal to noise ratio. If you take 20 images the noise will be different in each one so the stacking program can assume that features that appear in all images are signal and the rest is noise (put very simply). If you just duplicated a single image then the noise would be the same in all and there would be no benefit to stacking.

They describe the use of the different types of images for stacking here: http://deepskystacker.free.fr/english/faq.htm

[Nzlowie]

Cool thanks for the simple explanation. Makes sense.

Chhers

[jjjnettie (Jeanette)]

Sadly it won't work Dave.
Think of each image as a piece of fly screen mesh. If you stack them neatly one on top of each other, you will still be able to see through the little holes.
When you take an image, you fill some of the holes in the mesh (pixels) with data. Some fill quickly (bright regions of the picture) some will be partially filled (darker regions of the image).
Each image you capture is slightly different, so when you stack your photos you will be filling more of those holes with data, and the final image will be smoother and have more detail.
Hope you can understand what I mean.

[blink138 (Pat)]

Originally Posted by jjjnettie

Sadly it won't work Dave.
Think of each image as a piece of fly screen mesh. If you stack them neatly one on top of each other, you will still be able to see through the little holes.
When you take an image, you fill some of the holes in the mesh (pixels) with data. Some fill quickly (bright regions of the picture) some will be partially filled (darker regions of the image).
Each image you capture is slightly different, so when you stack your photos you will be filling more of those holes with data, and the final image will be smoother and have more detail.
Hope you can understand what I mean.

very good analogy nettie!
pat