Newts - maximum useful magnification?

[Gonariu]

18 hours ago, John said:

One thing I have noticed, over and over again, is that a good refractor is capable of delivering to it's full performance potential much more often than larger aperture newtonians that I've owned.

50x per inch of aperture is an often cited top end "limit" for scopes. My newts have only very occasionally been useful to use at 50x per inch, most often half of that is where they have topped out, most nights.

Contrast that with my refractors where 50x per inch is very often entirely comfortable and quite frequently 75x per inch can be usefully employed.

I put this largely down to the UK seeing conditions but I guess obstructions, diffraction, reflective vs refractive efficiency and system optical accuracy (rather than just the primary) come into play as well.

Doesn't help with your decision making much though !

 

 

I agree, I have a Newton Starfinder 8" (203/1200) which I am not currently using (I would have to redo the collimation properly); the magnification I use on the Moon and planets is X150-X200. I very rarely use X300 with good results, at this enlargement I once saw Gassendi's internal rhymes well, but it was the only one. I don't think the skies over England are the limit, here in Sardinia I am at 40 N and with many fewer rainy days than the UK. my Vixen 102 M 333X can be used profitably much more often.