[Aavso-photometry] Time series for GK Persei

[Jim Roe]

gianlucaros at gmail.com wrote:
> Hi Tim,
> yes they are filter images as I always use a V filter with my CCD. I
> have a fast Newtonian (8" F/4) which probably saturate faster than a
> 12" SCT but longer exposures are always better.

I'm afraid this is a common misconception.  F/# does not improve the 
exposure of point sources (like stars) - aperture rules!  F/# impacts 
exposure of extended objects like nebulae.

Jim Roe [ROE]
Wentzville, Missouri