Reducers and FWHM values

[Rodd]

Looking for some insight on how the use of a reducer impacts FWHM values.  I know its tough to compare directly due to the fact that seeing impacts FWHM,   I do not have any "without reducer vs with reducer" data from a single session to review.  That is because I have never made such a change in the middle of a session because I find such changes difficult and time consuming.  Threads that won't come apart do not help!  But any imput is better than none.   It stands to reason that as resolution goes down, FWHM values will go up (with same camera).  I say this because the smallest a star can be is one pixel.  The more arcsec per pixel, the larger the star in arcsec.   Say an image was taken at 3.5 arcsec/pix  with an FSQ and 11000 sensor.  1 pixel is 3.5 arcsec and  two pixels is 7 arcsec.  I would expect a good image in this case to have FWHM values reported around 4-5 arcsec.   But if the same region of sky is imaged at a pixel scale of 1.0 arcsec/pix, I would expect good data in average seeing to yield FWHM values of 2-2.5 arcsec.

Anyone have experience with reducers?  I am attempting to judge the quality of recent subs captured using a reducer

Thanks,

Rodd

Edited June 2, 2020 by Rodd