It's possible to pick up additional details this way (I guess it's analogous to using a lower ISO than available on the camera). If you take a photograph of same static image multiple times and average the individual images by stacking, then you get a stronger signal to noise ratio since the different noise between images gets averaged to a lower level while the signal is preserved. In this way, you can get the long exposure needed in astrophotography but reduce or eliminate star trails.Īnother benefit of stacking is to realize improved resolution through multi-sampling. The benefit of having individual exposures is that if there is subject movement, then the motion blur is much reduced on each individual exposure vs the full long exposure, and you can try to align the individual images before combining them. If you simply combine the exposures (a simple example of stacking), in principle you should get the long exposure back. Think of taking a long exposure and breaking it into shorter individual exposures.
Someone else probably can explain much better than I can, but seeing as nobody has responded yet I'll chip in with my understanding. If I may ask a rudimentary question: what is the purpose/goal of stacking astrophotography photos? I understand merging exposures for hdr, but what is the deal with stars, the moon, whichever? I would like to find out as my girlfriend loves everything astronomy.
