Illustrating Eyepiece Performance

[Macavity]

Since expressions like "Sharp to within nn% of the Edge" is often used to attempt to vaguely quantify performance of eyepieces, I wonder: Would it be possible (Afocal photo?) to produce some sort of crude "standard" photograph(s) to illustrate this?

I know, diversity of setup! But perhaps to first approx., (fast) scopes have a focal length of ~1200mm, most interest would be with eyepieces f~30mm. A magnification of ~40x, True Field of View ~1.5Deg. Maybe M45 (Pleiades) as the target? Feasible? Possible?

OTOH, who would want to expose possible defects in their equipment...

[James]

It'd be fascinating to see such a picture as eyepiece reviews could be based in reference to that picture.

James

[lunator]

Mac

There would be quite a few variable to take into consideration imparticular the quality of the camera lens.

My scope is an F6 Newt and using Orthos means that coma is visible at the edge using lower power 18/25mm eyepieces.

The object has to be very close to the edge to show this and I don't tend to view things there.

With all opitical systems there are trade-offs and for the cost of the scope/eyepiece combination a small amount of coma is not an issue.

I could spend alot more on sorting this but it not worth it IMO.

Cheers

Ian

[Macavity]

Yeah, I sensed it would be difficult (lots of variables) in a practical setup. Refractors versus reflector, use of Paracorr devices etc. Or perhaps a simulation might work better as a test card. Random (or a genuine starfield) dots inside target circles and subjected to increased blurring with radial distance. Who knows...