This may be because of the shape of the PSF is different from the normal airy disk one.
Here is a random google result showing the spot of arago, https://www.lighttrans.com/use-cases/application/observation... -- which looks to me like it would have poor contrast but good resolution. Though I'm out of my depth so it could be nonsense. :P
Edit: Ah, yeah the graph at figure 9 in the report linked on the linked page shows something like that.
This may be because of the shape of the PSF is different from the normal airy disk one.
Here is a random google result showing the spot of arago, https://www.lighttrans.com/use-cases/application/observation... -- which looks to me like it would have poor contrast but good resolution. Though I'm out of my depth so it could be nonsense. :P
Edit: Ah, yeah the graph at figure 9 in the report linked on the linked page shows something like that.