I use my 152 F5.9 achro mainly for clusters, extended nebula and the brightest galaxies. With a Panoptic 35 in the diagonal (26x, 2.5 degrees FOV) it is a perfect tool for low power milky way sweeping. Those pinpoint, sparkling stars across the whole FOV make you smile and then that contrast! M42 for example is really wonderfull with a lot of nebulosity in more then 50 shades of grey and 6 pinpoint trapezium stars in the centre. Point at any open cluster and you know why you should get or bought an 6" achro. An 6" APO is even better, but at a cost. For the mentioned targets, an achro is more then OK.
Would I buy one again? Yup, but not an F5, because it has too much CA. I got one but sold it quickly because of the amount of CA and poor optical quality. Tried a 6" newton, but sold it quickly because of the amount of coma. After that, tried a 6" mak, but sold it (not so quickly this time) because of the cooling down time and restricted FOV. Finally I bought my current 6" achro and I'm very happy with it.
I use mine (20 lbs) sometimes on a Orion Sirius but mostly a Giro II. A longer 6" might be challenging for an AVX, a F6 will be OK but is at the max for an AVX, a F5 is no problem.
Edited by Edwin, 06 January 2018 - 06:48 PM.