bautforum backwards,,,original. To address your problem, in recent conventions, astronomical journals have made a mandatory sizing on imaging submitted to journals just to address that issue. Images must have a common conventional format so that when accessing a databank, you can easily superimpose images from all parts of the spectrum...radio, microwave, near & far infrared, visible, ultraviolet, X ray, and gamma ray. Subtle effects not otherwise noticed can sometimes be seen that way.
For an amateur, the forum on astrophotography has excellent members' knowledge and should prove a big help to you. For a rookie to try to image using all the systems the pros do is probably prohibitively expensive unless you are a billionaire, you are likely to be better off picking a specialty, or perhaps two, and trying to master that. Good luck. pete

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A third rate theory forbids.
A second rate theory explains after the fact.
A first rate theory predicts.
A. Lomonosov