# Stargazing How to find the Point Spread Function of a Newtonian Telescope?

1. Aug 10, 2011

### Rana13

Hi everyone. I am a research undergrad student at the University of Washington and I have been given a conceptual problem to figure out for my astrophysics group...

My professor would like us to explain to how how one would find the point spread function of a Newtonian telescope.

Here's the kicker, I am NOT allowed to be given the answer, and so I am not here looking for the answer but more for GUIDANCE :)

I will list the following of what I know and where I am stuck, and what I dont understand:

I know the basic diagram of a Newtonian telescope. I know that light enters the chute and is reflected from a concave mirror (on the edges) which is then reflected back to a tiny slanted mirror (in the middle) which gives us the image into our focus piece.

Because the image isn't digital (or is it?) Im confused here on what Ill be seeing. This would be my true image of the sky, correct?

I know that from the true image of the sky, you can from there find the Point Spread Function (which as I understand it, is our SENSITIVITY from the sky) from the inverse Fourier Transform.

Im completely stuck though as to how I get from one part to the next. I get something from the Newtonian telescope...an image...what image this is, I have no idea. I know from there I can get to my PSF using fourier transform.

Again Im very new to this, I just learned these concepts recently and I am not well studied on astrophysics, telescopes or any of this. This is quite beyond my mere Associates of Science degree but Im learning and also trying. Any help or guidance would be fantastic :)
I have some knowledge of the math between baselines, psf, true image, power etc.

2. Aug 12, 2011