Jump to content


can you take an image of an Airy Disk??

Recommended Posts

I know you can easily see the Airy disk under steady seeing conditions with good optics, but can you actually take an image of the Airy disk??

( The maximum diameter of the central peak of the Airy disk is = 1.342 x Focal ratio (micron) - for green light)

Link to post
Share on other sites

I think I agree...

If we have a CCD camera with a 7.5 micron pixel, and say go for an oversampling of 4 pixel (?) then the focal ratio would have to be

(4 x 7.5)/1.342 = f22....

Not an uncommon f ratio for planetary imagers....

Link to post
Share on other sites

Exactly, I'd go even higher when possible , even F36/48 would give you a nicely defined airy disk out to the third ring etc...

I've always wanted to try eyepiece projection for planetary imaging to try to push for these higher F numbers. Until now I have never gotten around to it?

Link to post
Share on other sites

I'm sure I have some images of a airy disc taken through an aperture mask. I'll see if I can find them tomorrow.

As well as high f/ratio, you also need a short exposure time (i.e. webcam). The eye is very good at seeing/ignoring the short term instabilities in the image which blur out a longer exposure.

In the meantime, the most impressive on-sky airy disc image I've ever seen is from the Large Binocular Telescope in Arizona (though only using one of the telescopes). Their adaptive secondary produced a fantastic image with 10 airy rings visible (just). The excess of light outside the 10th airy ring is an artefact of the adaptive optics system. I'm pretty sure this image is log-scaled.

Image is from this webpage, which also has more info; Untitled Document


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.