I use a Vixen Fl102S refractor for my astrophotography. I operate it at f/9 (a little more, but may as well say f/9). It handles anything I point it at well, in fact VERY well, and is only "hampered" by a lack of aperture (I don't perceive it as much of a hampering really!).
I also have a dedicated f/4 astrograph R200SS Newtonian (8"). The exposures are shorter for a comparable result (not as aesthetically pleasing IMHO because of the darned diffraction spikes).
I have never put a focal reducer on the Fl102S (though do want one), but at present, I can live with it being f/9. I have taken better pictures with it than all the other scopes I have/had.
The only time I use the R200SS is when there is cloud about, as I can fit in more exposures in a shorter time span.
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