Nick, Re. the very bright meteor image – one way you can do photometry on the image to measure its brightness is to calibrate the degree of attenuation in the lens system of the internal reflection, which can be seen diametrically opposite a bright source across from the optical axis. See the secondary reflected image of the meteor towards the bottom of the frame. Try imaging a bright planet so you can integrate the light of the secondary image of it. Then image a starfield and calibrate the zeropoint of the direct image. You can then determine the equivalent brightness of he secondary image and therefore the attenuation factor in the lens.