Theoretical best Resolution on Focal Plane

[romi]

Can anyone comment on the following:

In principle, the Resolution of a telescope is inverse- proportional to the Focal length and is given by (approximately): Phi = 116 / F (Phi in [arcsec] and F [mm]).

Now, the size (1D) of an arc on the Focal Plane (or CCD plane) is given by (approximately): d = Phi F / 206 (d in [microns])

It therefore follows that the theoretical size of the best resolution of a telescope (ANY TELESCOPE) is app. 0.5 microns, independent of scope features (assuming no additional

optics of course, such as eyepieces and barlow lenses etc.). "seeing" is also ignored here....

[dph1nm]

The spatial resolution of a telescope is proportional to lambda*f/D, where lambda is the wavelength of light, f is the focal length of the telescope and D the objective/mirror diameter. So I think your first statement is wrong.

NigelM

[romi]

I agree. I got the first expression wrong and indeed it is more like Phi = 116 / D ant not F.

Thanks.

[ollypenrice]

And then there's there's the seeing...

And then there's the reality... (A 6 inch SCT will not, in my view, resolve at he the level of this 5.5 inch apo; http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=1793652809&k=39n8qx9&lb=1&s=O I'll be glad to be proved wrong. (Well, not glad but I'll take it like a gentleman! )

Olly

[JamesF]

There's probably the quality of the optics to consider as well, Olly.

James

[JamesF]

I agree with Nigel. The theoretical resolution is also dependent upon (proportional to, according to Rayleigh) wavelength. Across the visible spectrum that would probably mean a doubling (or thereabouts) of the theoretical resolution as you moved from red to blue.

James