I think this was 12.5mm eyepiece projection ?(ISO 400)

 which may explain the graininess.

And here was the video:

I learned some new things about my camera as well.

Why ISO 400?  8" is not a lot of aperture and with 12.5mm eyepiece projection that is not a lot of light.  Going to 400 gave me a recognizable image in LiveView mode.  I also discovered that video mode gave me an ISO range from 100 to 3200.  (Still mode goes to 57600.)

I have thought of going to a higher resolution camera.  Instead of 20.2 Mp, perhaps 40 Mp which would allow me to zoom in without having to use so much magnification.   Just crop the image.

This is the first time I have used the PhotoEditor on my Android.

This picture was taken through an 8" f/7 reflector my father and I built in 1970 or so.  This is why I needed ISO 400.  I will use my 17.5" f/4.5 next.  That gathers 4.78x the light so ISO 100 should be sufficient and less grainy.  Or perhaps a 25mm eyepiece which should give 2x the light?