This video presentation examines multiple factors affecting Astrophotography System sensitivity (i.e. the Limiting Magnitude), and see how much they individually contribute to overall system degradation (actual data in magnitudes).
The presentation quantifies the dependence on Aperture, OTA type, Optics Coatings, Camera QE (with imager comparisons), Seeing, Light pollution, Extinction…
https://nlobs.com/acad-intro/
or
https://youtu.be/8RN_uc2f6NM
This is a must see for all astrophotographers, beginners and experienced alike.
PDF of this presentation and other goodies are available from:
https://nlobs.com/resources/
~Chris K.